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Most shark-induced human fatalities are followed by widespread and unselective culling campaigns that have limited effectiveness and may have high ecological costs for threatened species. The blanket culling strategy implicitly assumes that incident risk is directly correlated with shark density, an assumption that has yet to be demonstrated. We present the alternative hypothesis that incidents are more likely to be caused by behavioral variability among individual sharks than due to shark density. Throughout their ontogenetic development, large species of sharks opportunistically establish a diet that is rarely, if ever, inclusive of humans as a food source. We propose that, some animals with specific behaviors (including boldness) may potentially pose a higher risk than conspecifics. Under this scenario, the risk of a shark attack in a given area would relate to the presence of a limited number of high-risk individuals rather than shark density.
In terms of management of human fatalities, such a hypothesis would favor abandoning general culling campaigns and replacing them with approaches that profile and selectively remove the potential problem individuals, as is done in the terrestrial realm when managing predators that attack humans or livestock.
To adapt to their environment, organisms can either directly interact with their surroundings or use social information (i.e. information provided by neighbouring individuals). Social information relates to the external features of surrounding peers, and little is known about its use by solitary species. Here, we investigated the use of social cues in a solitary marine predator by creating artificial aggregations of free-ranging sicklefin lemon sharks (Negaprion acutidens). Using a novel monitoring protocol, we analysed both dominance interactions and tolerance associations between sharks competing for food in relation with the number, the morphology and the behaviour of rivals. Sharks produced more agonistic displays and spent more time around the bait as competitors were more abundant. Moreover, the morphological attributes of competitors had very limited influence on the structure of shark social interactions. Instead, sharks appeared to establish tolerance relationships with competitors according to their individual behaviour. Furthermore, the more two sharks were observed together at a given study site, the fewer agonistic interactions they exchanged. We discuss these findings as evidence of the use of social cues in a non-gregarious predatory species and suggest directions for future research.
Size assessment and species identification are paramount after a fatal attack for profiling a ‘problem-animal’ that could be specifically eliminated. In addition to ecological and behavioural data about candidate species, forensic analysis can provide critical information for achieving this goal. After providing basic information about fatal attacks and the anatomical features of the three species (white shark, tiger shark and bull shark) that are responsible for >80% of lethal interactions, this chapter presents the most used tools for assessing the species and size of a potential attacker. The size assessment can be done through measurements (on the body of the victim or from good-quality photographs) of the bite width (BW) and bite circumference (BC); the size is then obtained from regressions from the literature between BW/BC and total length. The average interdental distance (IDD) is also used through a similar process. Finally, other details of the wounds, such as the shape of the bite margin or of flesh flaps that directly depend on the jaw characteristics, can also be used to contribute to the final assessment. Although important, a forensic analysis should be complemented by data on shark ecology and behaviour for a more reliable conclusion.
MPAs enhance some of the Ecosystem Services (ES) provided by coral reefs and clear, robust valuations of these impacts may help to improve stakeholder support and better inform decision-makers. Pursuant to this goal, Cost-Benefit Analyses (CBA) of MPAs in 2 different contexts were analysed: a community based MPA with low tourism pressure in Vanuatu, and a government managed MPA with relatively high tourism pressure, in Saint Martin. Assessments were made on six ES: fish biomass, scenic beauty, protection against coastal erosion, bequest and existence values, social capital and CO2 sequestration, which were quantified via different approaches that included experimental fishery, surveys and benefit transfer. Total operating costs for each MPA were collected and the benefit-cost ratio and return on investment based on 25-year discounted projections computed. Sensitivity analyses were conducted on MPA impacts, and discount rates (5%, 7% and 10%). The investment indicators all showed positive results with the impact on the tourism ES being the largest estimated for all MPAs, highlighting the importance of this relationship. The study also demonstrated a relatively high sensitivity of the results to different levels of impacts on ES, which highlights the need for reducing scientific knowledge gaps.
The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyze a global dataset of ∼2.8 million locations from >2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim,walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they
move through, resulting in complex movement patterns when moving close to coasts compared with more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal microhabitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise, and declining oxygen content.
An accurate assessment of the biting shark size is paramount for better understanding the agonistic behavior of a species toward humans. The gray reef shark is involved in many accidental bites. Based on the capture of 35 gray sharks, we calculated the algorithm that allows the assessment of the shark size, through the interdental distance (IDD) inferred from teeth marks on human wounds. Our results show a negative allometric relationship and that IDD calculated from imprints perpetrated by the upper jaw are globally similar with those from the lower jaw, in spite of heterodonty. We applied our findings to two cases of accidental bites by this species. Both of the victims had declared that the shark length was “at least 2 m”. Based on our algorithm, the assessment of the shark TL was approx. 180 and 160 cm, respectively, which correspond to an overestimation of ≥20% by the victims.
Eric CLUA, vétérinaire-chercheur français, étudie avec une équipe australienne les déplacements des grands requins en Nouvelle-Calédonie en posant des balises acoustiques et satellitaires sur les animaux.
2010 – Bilan sur l’étude du déplacement des grands requins en Nouvelle-Calédonie en collaboration avec Jonathan Werry, chercheur australien
La suite de l’étude sur le déplacement des grands requins en collaboration avec un chercheur australien
Suite à une attaque mortelle sur un jeune surfeur, les pêcheurs de Bourail lancent une campagne de pêche aveugle
Etude du déplacement des grands requins en Nouvelle-Calédonie en partenariat avec un chercheur australien
Actualités avec les participants de l’atelier IFRECOR autour d’une plongée dans le grand sud.
2006 – Actualité sur le classement des Bélep au nord de Nouvelle-Calédonie en zone prioritaire de conservation
Actualité sur la classification du lagon Sud en zone prioritaire de conservation
2005 – Direct émission avec E Clua interrogé par Prisca Rabenjoro
Clôture de l’atelier de lancement du programme CRISP à Nouméa avec tous les organismes participants.
Atelier de lancement du programme CRISP à Nouméa avec tous les organismes participants.
Atelier de lacement de l’analyse éco-régionale conduite par le WWF en Nouvelle-Calédonie, sous l’égide du CRISP
Portrait dans l’émission THALASSA (France 3) de Eric CLUA, vétérinaire, qui travaille sur les requins en Nouvelle-Calédonie
Short movie showing the methodology for tagging (acoustic and satellite) Tiger shark in New Caledonia for studying the movements of these animals.
Studies conducted in New Caledonia on shark genetics, based on the DNA sampling through free diving with adapted spearguns for underwater biopsies..
Thomas est un étudiant en thèse de biologie marine qui travaille sur la génétique des requins à pointes noires en Nouvelle-Calédonie sous la supervision de Eric CLUA, vétérinaire spécialiste des requins.
Les récifs coralliens jouent un rôle critique dans la vies des peuples océaniens. Du Vanuatu aux îles Salomon, ce documentaire aborde ce rôle sur un plan économique à travers les exemples de la pêche, la vente de corail, les aires marines protégées, le marché de l’aquariophilie, etc.
Film didactique (images + texte écrit) pour présenter la problématique des effets du changement climatique sur les récifs coralliens, préparée dans le contexte de la COP21 à Paris en décembre 2015.
Film humoristique qui a obtenu le prix du jury au Festival Mondial de l’image sous-marine de Marseille en 2013. Traitement par l’absurde de la pollution des océans par les macro-détritus… Baoummmm !!
En 2002, une jeune baleine est venue se réfugier dans une baie au sud de la Nouvelle-Calédonie pour fuir les prédateurs de la haute mer. Affamée et à bout de force, elle a succombé aux attaques des requins dans un spectacle aussi spectaculaire que triste et émouvant. Impuissant devant les lois de la nature, un scientifique a documenté cette longue agonie et mort tragique…
A mi-chemin entre la Nouvelle-Calédonie et l’Australie, au milieu de la Mer de Corail, un ensemble d’ilôts constitue à la fois un relais pour les espèces pélagiques tels que les requins et baleines, et un oasis de vie où foisonnent les coraux, oiseaux, poissons et autres reptiles. Récifs autrefois redoutés par les marins, les Chesterfield constituent aujourd’hui un enjeu de conservation mis en péril par la pêche illégale. Une mission de douze scientifiques a entrepris de faire un état des lieux de cet oasis de vie…
Tous les ans à la pleine lune des mois de juin et juillet, des milliers de mérous se donnent rendez-vous dans la passe d’un atoll des Tuamotu, inexorablement attirés par l’instinct de reproduction. Mais ils ne sont pas les seuls, leurs principaux prédateurs sont là aussi. Obnubilés par la ponte qui doit s’effectuer en pleine eau, loin de leurs cachettes, les mérous sont la proie des requins à l’affût, sous l’oeil des scientifiques. Prendre des risques pour perpétuer leur espèce, tel est leur destin…
Face à la raréfaction des ressources marines, certains chasseurs sous-marins se tournent vers une approche plus qualitative qui privilégie la capture de poissons exceptionnels au détriment d’une quantité maximale de poissons. Le thon à dent de chien, par sa taille importante mais surtout sa puissance, est une proie mythique. Un groupe de chasseur part à la recherche de ce poisson dans les passes des récifs coralliens du Nord de la Nouvelle-Calédonie, en quête d’un record de monde…
L’océan est le théâtre d’interactions incroyables entre gros prédateurs et leurs proies. Aux Açores, les dauphins sont connus pour agréger les bancs de petits poissons pour se nourrir plus efficacement. Repoussés à la surface, ces « boues d’appâts » deviennent aussi la proies des oiseaux marins qui plongent dessus avec avidité, quand ce ne sont pas des thons géants ou des marlins venus du fond qui profitent aussi de la curie. Ce documentaire suit des scientifiques qui étudient ce phénomène de coopération naturelle…
La Nouvelle-Calédonie détient le plus grand lagon du monde et se positionne comme un endroit privilégié pour le développement de l’apnée. C’est ainsi que s’est développé sur Nouméa, la capitale, un club qui est devenu, au fil des années, le plus grand club d’apnésites au monde, avec plus de 200 licenciés par an ! Ce documentaire décrit les activités du club, en piscine mais aussi en milieu naturel, sous l’impulsion de passionnés du grand bleu…
La passion de nombreux aquariophiles pour les espèces tropicales a entrainé le développement d’un marché florissant autour de certains poissons aux couleurs éclatantes. C’est le cas du « flame angelfish »(Centropyge loricula), un poisson ange d’un rouge écarlate qu’on trouve sur les pentes externes des récifs du Pacifique insulaire. Ce poissons constitue la ressource principale de l’île de Christmas au large des Hawaii, où il est pêché par une horde de plongeurs qui, face à sa raréfaction, sont obligés d’aller le chercher de plus en plus profond, au péril de leur vie. Cette tragédie commerciale a valu à cette île le surnom de l’île au « dollar-fish »…
Les animaux constructeur de récifs que sont les coraux ont la faculté de se reproduire de façon végétative et peuvent se greffer, tels des arbustes. C’est sur ce prinicpe que repose la restauration récifale qui permet de réimplanter des coraux dans un endroit où ils ont disparu. Cette technique est notamment employée en tant que mesure de compensation d’une activité humaine qui affecte le milieu corallien. Ce documentaire court décrit un des premiers exemples de restauration corallienne en Nouvelle-Calédonie…
Eric invité de l’émission Direct avec Prisca Rabenjoro
Portrait dans le magazine « la semaine vétérinaire »
The extent of the global human footprint limits our understanding of what is natural in the marine environment. Remote, near-pristine areas provide some baseline expectations for biomass and suggest that predators dominate, producing an inverted biomass pyramid. The southern pass of Fakarava atoll—a biosphere reserve in French Polynesia—hosts an average of 600 reef sharks, two to three times the biomass per hectare documented for any other reef shark aggregations. This huge biomass of predators makes the trophic pyramid inverted. Bioenergetics models indicate that the sharks require ∼90 tons of fish per year, whereas the total fish production in the pass is ∼17 tons per year. Energetic theory shows that such trophic structure is maintained through subsidies, and empirical evidence suggests that sharks must engage in wide-ranging foraging excursions to meet energy needs. We used underwater surveys and acoustic telemetry to assess shark residency in the pass and feeding behavior and used bioenergetics models to understand energy flow. Contrary to previous findings, our results highlight that sharks may overcome low local energy availability by feeding on fish spawning aggregations, which concentrate energy from other local trophic pyramids. Fish spawning aggregations are known to be targeted by sharks, but they were previously believed to play a minor role representing occasional opportunistic supplements. This research demonstrates that fish spawning aggregations can play a significant role in the maintenance of local inverted pyramids in pristine marine areas. Conservation of fish spawning aggregations can help conserve shark populations, especially if combined with shark fishing bans.
The identification and economic valuation of ecosystem services (ES) are becoming important components of coral reef management. In many contexts, protection of human assets against coastal floods is one of the most important ES provided by coral reefs. The methods utilized to characterize this ES should be able to accommodate situations with low data availability, without sacrificing robustness. In this paper, we suggest such an approach that utilizes expert opinion and does not require copious amounts of data. Our primary objective is to find a balance between simple and complex models that can be used in a data scarce environment, to produce an economic valuation of the coral reef ES of protection against coastal floods. The approach has three steps: (i) identify geographic zones and assets at risk, (ii) identify the contributing role of coral reefs in the protection of coasts and, (iii) value the annual repair costs of assets through the avoided damage cost approach. The proposed method seems appropriate for advocacy with policy makers, but appears to be less effective for small scale approaches, such as those required for Payment for ES negotiations or marine spatial planning.
As the giant trevally is absent from the list by Fourrière et al. (2014), we present here the first record of C. ignobilis in the waters surrounding the Clipperton atoll.
We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO2]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO2) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (-0.86 bpm.%(-1)) while HR kinetics in NDs steadily decreased throughout BH (-0.47 bpm.%(-1)). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (-7.3 ± 3.2 vs. -3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an « oxygen-conserving breaking point » in the human diving response.
Sharks are marine predators that constitute a potential threat to humans and their specific behaviours often play a critical role in triggering fatal attacks (Clua & Séret 2010; Clua & Reid 2013; Clua et al. 2014). Several authors have recently outlined the economic importance of shark-based ecotourism which far outweighs the single-use income obtained from fishing (Clua et al. 2011; Gallagher & Hammerschlag 2011; Vianna et al. 2012). However, the development of such activities increases the potential interactions between sharks and humans and the correlated risk of accidental bites (Brena et al. 2015), in particular when unsuitable provisioning practices such as hand-feeding are implemented (Clua & Torrente 2015). In such a context, a better understanding of shark agonistic behaviours is indispensable.
In a valuable response to this challenge, Aidan Martin published a paper entitled ‘A review of shark agonistic displays: comparison of display features and implications for shark-human interactions’ (Martin 2007). This paper focuses on the behaviour of 23 shark species and includes supplementary online material (SOM) composed of several videos displaying specific shark behaviours (see Figure 1). These are available at: http://www.tandfonline.com/ doi/suppl/10.1080/10236240601154872. The nine files that can be downloaded include the following common text ‘gmfw_a_215414_sup_’ with an additional number ranging from 001 to 009; a short description of the video clip is also provided. One would expect these files that are ranked by increasing numbers to correspond to the video clips in their citation order in the text (as video clip 1, 2, etc.). There are, however, some discrepancies between the text and the SOM as well as some missing material.
Une expédition de nature écotouristique privilégiant la plongée et une démarche de « science participative » s’est déroulée du 28 janvier au 11 février 2016 autour de l’atoll de Clipperton et dans l’archipel mexicain des Revillagigedos. Organisée par une société canadienne, la logistique a été assurée par le navire Quino El Guardian, un troller américain de 28 m basé au port de San Jose del Cabo (Basse-Californie mexicaine) et géré par un équipage mexicain de neuf personnes (incluant deux moniteurs de plongée). Le groupe de 11 touristes relevant de sept nationalités (Mexique, USA, Pologne, Porto Rico, Canada, Grèce et Angleterre) était géré par les deux chefs d’expédition canadiens (Michel Labrecque et Julie Ouimet). Ils ont bénéficié de l’encadrement technique de trois scientifiques respectivement franco-colombien (Sandra BesSudo), mexicain (Mauricio Hoyos) et français (Eric Clua).
Based on new photographs of the wound, Tirard et al. (2015) tried to demonstrate that the shark involved in a fatal attack on a human in Lifou in 2007 had homodont teeth and that it sawed the femur instead of directly cutting it, promoting the hypothesis that it was a tiger shark instead of a white shark. They also contested the data provided by the direct witness of the attack about the behaviour of the shark, specific to this former species. The evidences they provide are not convincing and, based on the absence of tissue loss and description of a jumping behaviour, we still believe that it was a single bite-and-spit attack by a white shark.
The decline of meso-predators such as reef sharks is a concern as such species can have important ecological roles in maintaining reef ecosystem resilience. Two field trips conducted in August 2010 and November 2011 to the Chesterfield archipelago (Coral Sea) allowed us to assess the abundances and average sizes of medium-bodied Carcharhinidae with a specific focus on grey reef shark (Carcharhinus amblyrhynchos), through fishing (46 hours of accumulated effort) and underwater visual censuses (25 hours of accumulated effort). We found low abundance and small average total length (TL) for all reef shark species, and in the case of the grey reef shark, an average abundance of 2.1 individuals/dive with the majority of animals less than 110 cm TL. We compared our findings with historical data and, given our low sampling effort, we so far hypothesise that a general strong decline in the reef shark populations may have occurred in this area, probably due to recent overfishing. The enforcement of conservation measures is strongly recommended among these remote reefs as well as complementary studies for confirming this hypothesis.
Shark-based ecotourism is significantly developping around the world, often without appropriate management of risk. This activity involves a risk of accidental bites on divers that can be quite severe or even fatal. Objectives: To determine if ecotourism companies’ liability can be engaged in the context of bites on scuba divers in presence of hand-feeding practices, supporting the legitimacy of financial compensation for the victims. Methods: We analyzed the development from the mid-eighties to 2010 of shark-based ecotourism through artificial provisioning practices in Moorea island (French Polynesia) and more specifically the features and motivation of two bites on divers by Sicklefin Lemon sharks. Results: The specific practice of hand-feeding can be considered as a facilitating factor for accidental bites on divers, potentially involving the diving operator’s responsability. Conclusions: Our findings should support the technical work of experts that might be called in such cases.
Qu’est-ce qu’un requin en Océanie ? A l’époque où nous vivons, la réponse est relativement claire et concise: un requin est essentiellement un poisson qui se mange, que l’on regarde et que l’on craint. Si l’on englobe des époques plus reculées, il convient de rajouter que le requin s’utilise aussi pour fabriquer des outils, des armes, des bijoux ou parures, et surtout qu’il se vénère et se déifie. Tout cela aboutit à de multiples façons d’appréhender les relations entre le requin et l’homme en Océanie. C’est ce que nous nous proposons de faire dans le cadre de cet ouvrage, avec une approche la plus scientifique possible. Mais si la rigueur sera de mise dans notre entreprise, notre souci premier sera de traiter ces multiples facettes de la façon la plus attrayante et légère possible.
This study determined the movements of a Giant Grouper, Epinephelus lanceolatus, in which an acoustic tag was surgically implanted and monitored by an array of six VR2W acoustic receiver units from August 2010 to January 2013 in the remote, uninhabited Chesterfield Islands, Coral Sea (800 km West of New Caledonia). Our data revealed a home reef area (residency rate of 44.9%) with an increased activity revealed by movements at dawn and dusk toward and between two adjacent reef passages, probably for foraging. The fish was absent from its resident reef between October and December 2010 and 2012, corresponding to the time known for spawning aggregations of this species in New Caledonia. A skipped spawning seems to have occurred in 2011. We hope these data will be complemented in the future by locating the spawning site or sites and thus provide adequate conservation measures. The Coral Sea links two World Heritage Sites, the Australian Great Barrier Reefs and the New Caledonian coral reefs. It would be fitting to create a Marine Protected Area for the Chesterfield Islands between these two major conservation areas of the sea.
The use of olfactory stimuli and the provision of food are a common practice to prompt artificial aggregations of emblematic wild species and ensure the economic viability of the wildlife-watching industry. Several elasmobranch species have been targeted by such operations in a variety of locations for over four decades. A recent review succinctly addressed the potential effects of shark diving tourism, including shark provisioning, on shark individual behavior and ecology, but the general paucity of data on the ecology of elasmobranchs precluded general statements. By using a functional framework, we reviewed the findings of the 22 available studies that investigated the behavioral, physiological, and ecological response of 14 shark and three ray species targeted by artificial provisioning. Focusing on the underlying processes that rule the response of targeted elasmobranch species, we report further effects acting beyond the individual-scale and their cross-scale relationships. We suggest that the most commonly described alterations of individual movement patterns have cascading effects through the group and community-scale, ultimately resulting in altered health condition and individual behavior toward humans. We conclude by stressing the potential for provisioning activities to support the investigation of complex ecological and behavioral processes in elasmobranchs.
L’intérêt de la pratique du yoga pour l’entraînement en apnée est indéniable du point de vue empirique mais il n’a été que partiellement démontré du point de vue scientifique. Au cours de ce chapitre, nous proposons de présenter dans un premier temps les principaux acquis scientifiques sur les vertueuses modifications induites par le yoga sur les paramètres physiques, physiologiques et psychiques de la performance en apnée. Nous abordons ensuite les rapports entre yoga et apnée sur un plan plus pratique en proposant des exercices couramment utilisés par les apnéistes adeptes de ces arts complémentaires. Nous présentons successivement des exercices empruntés au yoga postural (Hatha-yoga), à la science yogique de la respiration (prânayâma) ou encore à la relaxation. À chaque reprise sont indiqués les intérêts des exercices ainsi que les techniques de leur mise en œuvre. Un exemple de programme précompétition est enfin fourni à titre indicatif.
Après avoir passé en revue les grands principes de l’entraînement, ce chapitre se penche sur les spécificités liées à l’apnée. Il présente les facteurs contribuant à la performance en apnée : les facteurs anatomo-physiques, physiologiques, psychologiques et techniques. Ces facteurs sont étudiés en même temps que sont évoqués les exercices permettant leur amélioration. La quatrième partie du chapitre présente les éléments permettant la structuration d’un entraînement à l’apnée, par le biais de nombreux exemples d’exercices. Après être revenu sur les composantes spécifiques à l’entraînement en apnée que sont la sécurité et les souffrances psychologiques et physiologiques, le chapitre propose ensuite une méthode d’entraînement répondant à toutes les contraintes évoquées au préalable. Cette méthode repose sur l’utilisation des « performances acquises » permettant de minimiser le stress chronique hypoxique imposé par l’apnée, en ne travaillant simultanément que sur certains facteurs de la performance. Cette méthode présente des intérêts annexes pour la mise en œuvre d’un entraînement collectif, avec des niveaux hétérogènes chez les élèves et une sécurité maximale. En conclusion, l’accent est mis sur les lacunes actuelles qui engagent à maintenir la sécurité comme une composante majeure de l’entraînement en apnée.
Intra-guild predation (IGP), depredation of hooked sharks and cannibalism by large individuals on smaller conspecifics have been documented for both tiger shark Galeocerdo cuvier and bull shark Carcharhinus leucas. In this paper we report a case study of cumulative inter and intra-depredation from the Indian and the Pacific Ocean involving large G. cuvier and C. leucas adults at the final stage. These findings further the hypothesis that IGP and cannibalism among adult sharks occurs in the wild and potentially influences predator-prey relationships in tropical marine ecosystems.
A sole priority: Take action!
If the conclusions of the Pacific Coral Reef Institute (IRCP) workshop held on Moorea (French Polynesia) from 13 to 17 October 2014 had to be summed up in just a few words, the above statement, as simple as it is incisive, would probably be the best description. This symposium dealt with the overall topic of the sustainable development of shark populations in the South Pacific, particularly in response to pressures from humans. The meeting was funded at the initiative of the Pacific Fund for Scientific and Cultural Cooperation (French Pacific Fund), a French funding mechanism that promotes exchanges between French and English speaking territories in the Pacific, to work together on shared problems. Funding was also provided by the French Polynesia Shark Observatory (ORP), the IRCP and the French Ministry of Ecology, Sustainable Development and Energy. Sharks are a topic of concern and in order to better understand the priorities for ensuring sharks’ protection while maintaining their contributions to island economies, about 30 specialists from various countries and territories (Australia, Colombia, Fiji, France, French Polynesia, New Caledonia, the United Kingdom, the United States of America, and Samoa), divided equally between members of research agencies, non-governmental organisations, regional organisations, governmental bodies, and the private sector (commercial divers, veterinarians, journalists) met to determine the wording of a message to Pacific Island decision-makers and managers.
For free-swimming marine species like sharks, only population genetics and demo-graphic history analyses can be used to assess population health/status as baseline population numbers are usually unknown. We investigated the population genetics of blacktip reef sharks, Carcharhinus melanopterus; one of the most abundant reef-associated sharks and the apex predator of many shallow water reefs of the Indian and Pacific Oceans. Our sampling includes 4 widely separated locations in the Indo-Pacific and 11 islands in French Polynesia with different levels of coastal development. Fourteen microsatellite loci were analysed for samples from all locations and two mitochondrial DNA fragments, the control region and cytochrome b, were examined for 10 locations. For microsatellites, genetic diversity is higher for the locations in the large open systems of the Red Sea and Australia than for the fragmented habitat of the smaller islands of French Polynesia. Strong significant structure was found for distant locations with FST values as high as ~0.3, and a smaller but still significant structure is found within French Polynesia. Both mitochondrial genes show only a few mutations across the sequences with a dominant shared haplotype in French Polynesia and New Caledonia suggesting a common lineage different to that of East Australia. Demographic history analyses indicate population expansions in the Red Sea and Australia that may coincide with sea level changes after climatic events. Expansions and flat signals are indicated for French Polynesia as well as a significant recent bottleneck for Moorea, the most human-impacted lagoon of the locations in French Polynesia.
We present a case of a non-provoked fatal shark attack on a 15-year old male kitesurfer in New Caledonia. The victim lost his board and was pulled by the sail along the water surface in a reef passage when a shark attacked. The shark inflicted at least two bites on the left leg, including a severe one around the knee, resulting in a quick hypovolemic shock that was fatal. The analysis of one of these bites indicated that a 2.8 m TL (est. length) tiger shark was responsible for this attack. The features of the attack are consistent with those of a predator response to a surface feeding stimulus.
Despite its distribution throughout the tropics and subtropics, the pygmy killer whale (Feresa attenuata) is one of the most poorly known species of odontocetes (Cetacea: Delphinidae). We used the opportunity of a mass stranding of six animals in New Caledonia (early February 2006) to gather information about their biology. Four animals, including three males and one female, were found dead, and morphometrics, including dental counts, were collected. Two live mature males of 236 and 246 cm total length (TL), respectively, were closely monitored and sampled via blood analysis. As it was not likely to survive, the second animal was euthanized and necropsied. Following the euthanasia of the larger animal, the smaller one, which was probably staying out of social solidarity, returned on its own to the open sea. The necropsy revealed the presence of cardiopulmonary collapse and enlarged and congested testes. Blood parameters confirmed a deteriorating health status for both animals, enhanced by starvation. Some of the relative morphometric measurements of all six stranded pygmy killer whales seemed to be larger for these animals living in the southwest Pacific as compared to the literature for this species. We hypothesize that this group of pygmy killer whales was probably pushed through the Coral Sea toward the New Caledonian lagoon by Hurricane Jim, which occurred in the area from 26 January until 2 February. These observations reveal January as a potential part of the mating season in this area for this rare, elusive, and unknown species. It also supports the notion that early sacrifice of distressed, terminal animals could be a way to improve the survival rate of other less traumatized individuals during cetacean mass strandings.
L’écotourisme basé sur l’observation dans leur milieu d’animaux emblématiques est en plein essor à travers le Monde, et le Pacifique insulaire n’échappe pas à la tendance. Parmi ces espèces, les requins occupent une place privilégiée en tant qu’attraction pour les touristes, sans qu’ils soient forcément plongeurs. Une des caractéristiques de cette activité repose sur la nécessité d’avoir recours au nourrissage artificiel (feeding en anglais) afin d’assurer la présence d’animaux en quantité importante et en un lieu précis pour favoriser l’observation. Aussi, s’il permet indéniablement de dégager des revenus conséquents pour les économies locales, l’écotourisme basé sur l’observation des requins n’est pas sans poser certains problèmes en terme d’impact sur les écosystèmes, de sécurité pour l’Homme, voire de répartition légitime des dividendes qu’il génère (Clua et al. 2011). Un autre atout de cette activité repose sur le fait qu’elle renforce la valeur économique des requins aux yeux des décideurs politiques et ce, dans un contexte où ces animaux sont globalement surpêchés à l’échelle planétaire (Clarke et al. 2006), malgré les mises en gardes des scientifiques sur la nécessité de conserver ces super-prédateurs au sein des écosystèmes marins. Dans un contexte où les arguments écologiques ont montré leur limite sur les dernières décennies pour obtenir une vraie protection, une approche économique semble complémentaire et nécessaire pour assurer un développement durable des populations de requins dans le Pacifique Sud (Vianna et al. 2012). L’objet de cet article est de présenter les grands axes d’une telle approche économique, en mettant l’accent sur l’écotourisme en tant qu’utilisation vertueuse des requins, permettant de dégager des revenus tout en les maintenant dans leur écosystème. Cette approche ne peut néanmoins être totalement vertueuse que si elle respecte les trois volets fondateurs du développement durable, à savoir le volet économique, mais aussi les volets écologique et social. Cet objectif ne sera atteint que via la mise en place de « paiements pour services écosystémiques », comme nous allons tenter de le démontrer.
Ecotourism based on observing iconic animal species in their natural habitats has become increasingly popular around the world and the Pacific Islands are no exception to this trend. Among these iconic species, sharks hold a special place as an attraction for tourists, including tourists who are not divers. One of the characteristics of this activity is the need for artificial feeding to ensure that there are enough animals present in a specific spot to be observed. So, while shark watching undeniably provides significant levels of income to local economies, it does, however, raise a certain number of problems in terms of its impact on the ecosystem, human safety and even a legitimate distribution of the dividends it generates (Clua et al. 2011). Another advantage of this activity is that it strengthens sharks’ economic value in the eyes of decision-makers at a time when these animals are generally being overfished throughout the world (Clarke et al. 2006), in spite of scientific warnings about the need to preserve these super-predators within their marine ecosystems. Against a backdrop in which environmental arguments have shown their limits over the past few decades in terms of providing any real protection, an economic approach appears to be both complementary and necessary to ensure the sustainable development of shark populations in the South Pacific (Vianna et al. 2012). The purpose of this article is to present the general outlines of such an economic approach, highlighting ecotourism as a virtuous use of sharks that makes it possible to generate income while maintaining them in their ecosystem. Nevertheless, this approach is not totally virtuous unless it respects the three fundamental aspects of sustainable development: 1) environmental, 2) social, and 3) economic. This goal will only be reached through the implementation of “payments for ecosystem services” as we will attempt to demonstrate.
Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark-human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km(3). The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a priority for future research.
Le manuel amélioré du chasseur efficace et responsable
Cet ouvrage de référence s’est installé comme l’outil incontournable pour devenir un chasseur moderne, responsable et respectueux du milieu sur lequel repose sa passion : la mer.
Le chasseur sous-marin (débutant ou confirmé, sédentaire ou voyageur) est curieux de nature. À l’écoute de son corps, de son matériel, du milieu, il se pose un grand nombre de questions pour améliorer son efficacité.
Remplie d’astuces et de conseils de spécialistes, cette édition actualisée et complétée inclut tous les progrès en physiologie de l’apnée ou biologie des poissons pour mieux répondre à cet impératif de savoirs.
Conservation of threatened large sharks and management of shark-human interactions requires an understanding of shark occurrence and movement patterns. Here, we present the first catch, movement and behaviour data of adult bull sharks, Carcharhinus leucas, in New Caledonia. Amongst six adult C. leucas tagged with passive acoustic tags, four females were caught in coastal waters while males were only found at an isolated oceanic barrier coral reef over 100 km from the nearest river mouth. Two females were monitored in the southern New Caledonia lagoon for 707 and 208 days respectively and displayed classical transient behaviour and sporadic short-term residency around a coastal reef bay, with movements in and out a river detected prior to spring. Adult C. leucas in New Caledonia may develop a sex-based spatial segregation with an atypical presence of adult males in oceanic environments, probably influenced by the unique estuarine-marine continuum of the New Caledonian great lagoon.
Human pressures have put many top predator populations at risk of extinction. Recent years have seen alarming declines in sharks worldwide, while their resilience remains poorly understood. Studying the ecology of small populations of marine predators is a priority to better understand their ability to withstand anthropogenic and environmental stressors. In the present study, we monitored a naturally small island population of 40 adult sicklefin lemon sharks in Moorea, French Polynesia over 5 years. We reconstructed the genetic relationships among individuals and determined the population’s mating system. The genetic network illustrates that all individuals, except one, are interconnected at least through one first order genetic relationship. While this species developed a clear inbreeding avoidance strategy involving dispersal and migration, the small population size, low number of breeders, and the fragmented environment characterizing these tropical islands, limits its complete effectiveness.
We present the case of a non provoked fatal shark attack on a 19-year old male surfer in New Caledonia. Several severe bites removed the right arm and all flesh from the right thigh, provoking a quick hypovolemic shock that was fatal. The information provided by a witness and the analysis of a partial bite on the right calf allowed us to identify a 2.7 m TL (est. length) white shark as responsible for this attack. The features of the attack are consistent with a young predator motivated by hunger and the development of its predatory skills.
The population dynamics of shark species are generally poorly described because highly mobile marine life is challenging to investigate. Here we investigate the genetic population structure of the blacktip reef shark (Carcharhinus melanopterus) in French Polynesia. Five demes were sampled from five islands with different inter-island distances (50-1500 km). Whether dispersal occurs between islands frequently enough to prevent moderate genetic structure is unknown. We used 11 microsatellites loci from 165 individuals and a strong genetic structure was found among demes with both F-statistics and Bayesian approaches. This differentiation is correlated with the geographic distance between islands. It is likely that the genetic structure seen is the result of all or some combination of the following: low gene flow, time since divergence, small effective population sizes, and the standard issues with the extent to which mutation models actually fit reality. We suggest low levels of gene flow as at least a partial explanation of the level of genetic structure seen among the sampled blacktip demes. This explanation is consistent with the ecological traits of blacktip reef sharks, and that the suitable habitat for blacktips in French Polynesia is highly fragmented. Evidence for spatial genetic structure of the blacktip demes we studied highlights that similar species may have populations with as yet undetected or underestimated structure. Shark biology and the market for their fins make them highly vulnerable and many species are in rapid decline. Our results add weight to the case that total bans on shark fishing are a better conservation approach for sharks than marine protected area networks.
The economic valuation of coral reefs ecosystem services is currently seen as a promising approach to demonstrate the benefits of sustainable management of coral ecosystems to policymakers and to provide useful information for improved decisions. Most coral reefs economic studies have been conducted in the United States, Southeast Asia and the Caribbean, and only a few have covered the South Pacific region. In this region, coral reefs are essential assets for small island developing states as well as for developed countries. Accordingly, a series of ecosystem services valuations has been carried out recently in the South Pacific, to try and supply decision-makers with new information. Applying ecosystem services valuation to the specific ecological, social, economic and cultural contexts of the South Pacific is however not straightforward. This paper analyses how extant valuations address the various management challenges of coral reef regions in general and more specifically for the South Pacific. Bearing in mind that economic valuation has to match policy-making contexts, we emphasize a series of specific considerations when conducting and applying ecosystem services valuation in South Pacific ecological and social contexts. Finally, the paper examines the decision-making situations in which extant valuations took place. We conclude that, although ecosystem valuations have been effectively used as a means to raise awareness with respect to coral reef conservation, methodologies will have to be further developed, with multidisciplinary inputs, if they are to provide valuable inputs in local and technical decision-making.
Tiger Sharks, Galeocerdo cuvier, are large top-level predators usually solitary as adults. Observation of their scavenging activity on the carcass of a dead whale offered a rare opportunity for better understanding the pattern of intra-specific behaviour within the aggregations of these large predators. In January 2002, the stranding, subsequent death and consumption of a 17.4m total length (TL) blue whale, Balaenoptera musculus, was observed and filmed in Prony Bay, southern New Caledonia. After three weeks of confinement in the bay, the cetacean was killed by adult bullsharks Carcharhinus leucas. The first adult Tiger Shark was subsequently observed around the carcass after 36h. The fat slicks from the carcass attracted further Tiger Sharks which arrived after an additional 24h. The use of photo-identification on video footage collected during four observation sessions over an eight-day period identified 46 individual Tiger Sharks (primarily adult females between 3.3 and 4m TL) participating in the feeding aggregation. Only four animals were identified in two seperate observation sessions (over two consecutive days), suggesting a short-term residency pattern of several hours (<36h) around the carcass. As the arrival time of Tiger Sharks to the carcass differed, most arrivals of a new participant were followed by a frenzied period of intense intra-specific interaction. Different biting and agonistic behaviours were demonstrated by the Tiger Sharks on the carcass, including three new behaviours previously undescribed for this species. Size and level of aggressiveness appeared to be the determining factors of dominance amongst Tiger Sharks. These observations and analysis demonstrate that systematic study of feeding aggregations supported by photo-identification could contribute to knowledge of large shark ecology when coupled with capture-recapture, genetic fingerprinting and tagging techniques.
Several occurrences of White Sharks in tropical waters have been reported, but in the context of gaps in the knowledge of the ecology of that top predator, they appear as unusual and unexpected destinations. The New Caledonian exclusive economic zone covers 1,400,000 km2, with sea-surface temperatures oscillating between 20 and 21°C in winter and 28 and 32°C in summer. We have validated fifty-two sightings of White Sharks between 1943 and 2010, mainly based on professional fishing bycatches and observations at sea. We obtained information on season in thirty-nine cases, shark size in forty-seven cases, and gender in twelve cases. To this, we added information for six different animals that were tagged with pop-up archival tags in New Zealand in April 2005 (two sharks) and March 2009 (four sharks), before releasing their tags in New Caledonian waters a few months later. Fifty-two percent of the animals were spotted in winter (July to September), 26% in spring (October to December), 23% in summer (January to March), and none in fall (April to June), which corresponds with the best season for tagging them in New Zealand. Thirty-two percent of the sharks were shorter than 3.8 m total length (TL), 45% between 3.8 and 4.4 m TL, 15% between 4.5 and 5 m TL, and 8% above 5 m TL. The smallest animal was 2.6 m TL and the largest was 5.5 m TL. The sex ratio was unbalanced, with twelve males and six females. As in other tropical islands, the peak presence of White Sharks in winter coincided with that of humpback whales that come to mate and calve in New Caledonian waters in winter before leaving in October. The extended presence of White Sharks until the end of summer could be linked to other sources of food such as spawning aggregations of reef fishes and deep-sea snappers, in addition to other usual prey. New Caledonian waters appear to be a wintering ground for South Pacific White Sharks, and the study of their ecology should be addressed at a regional level for providing critical information aimed at ensuring their sustainable management in this part of the world.
Synopsis
Coral reefs are integral to the cultures and nutrition of many Pacific peoples; this report was developed to assist reef conservation for those peoples;
Most coral reefs in the Pacific remain generally healthy, with strong potential for recovery of coral, fish and invertebrate populations after damaging events;
There are, however, many signs of decline, especially on reefs around population centres and in lagoons;
The main drivers of changes in coral cover at larger scales include major ‘natural’ stresses in storms and cyclones, outbreaks of crown-of-thorns seastars (COTS) and coral bleaching driven by climate change;
The trends in coral cover vary considerably from country to country. Current reef status is a reflection of recent damaging events, predominantly ‘natural’, and most damaged reefs appear to be recovering. While trends in reefs can be detected for individual countries and territories, no strong Pacific-wide or regional trend is evident;
At more localised scales, coral reefs are driven by the interactions between many, environmental and human factors. These damaging human factors include: over-exploitation of fishes and invertebrates; sedimentation from poor land-use such as agriculture; mining of coral and sand; urban and tourism developments; and pollution from domestic and farming wastes;
Fishing and harvesting have definitely affected coral reef communities across the Pacific, especially in close proximity of towns, but the magnitude of these effects varies considerably between countries and islands;
Traditional management practices, such as permanent or temporary closure of fishing areas or bans on catching some species, remain particularly strong in the Pacific and are a major force for coral reef conservation;
Many countries and territories have sound legislation to manage coral reef resources, but lack the capacity, logistic resources and sometimes the political will to enforce these laws. However, many countries and territories are making efforts to improve capacity for enforcement and raise awareness of the need for reef conservation; and
Our conclusions are that the longer-term outlook for the coral reefs of the Pacific is considered to be Poor due to threats posed by climate change.
Ciguatera fish poisoning (CFP) is a common intoxication associated with the consumption of reef fish, which constitutes a critical issue for public health in many countries. The complexity of its epidemiology is responsible for the poor management of the risk in tropical fish markets. We used the example of the Noumea fish market in New Caledonia to develop a cost-effective methodology of assessing the CFP risk. We first used published reports and the knowledge of local experts to define a list of potentially poisonous local species, ranked by their ciguatoxic potential. Based on two 1-month surveys in the market, conducted in winters 2008 and 2009, we then calculated the consolidated ratio of biomass of potentially poisonous species vs. total biomass of fish sold on the market. The prevalence of high CFP-risk species in the market was 16.1% and 18.9% in 2008 and 2009, respectively. The most common high CFP risk species were groupers (serranids), king mackerels (scombrids), snappers (lutjanids), barracudas (sphyaraenids), emperors (lethrinids) and wrasses (labrids). The size (age) of the fish also plays a critical role in the potential ciguatoxic risk. According to proposals of average size thresholds provided by experts for high-risk species, we were also able to assess the additional risk induced by the sale of some large fish on the market. The data collected both from experts and from the market allowed us to develop a cost-effective proposal for improving the management of the CFP risk in this market. However, the successful implementation of any regulation aiming to ban some specific species and sizes from the market, with an acceptable economical impact, will require the improvement of the expertise in fish identification by public health officers and, ideally, the commitment of retailers.
Deux cas d’intoxications ciguatoxiques ont été relevés respectivement en janvier et mai 2010 suite à l’ingestion de poissons pêchés en Baie de Prony. Le premier cas repose sur l’intoxication légère de 4 personnes, dont un enfant, qui ont consommé de la chair de plusieurs loches saumonées (Plectropomus leopardus), dont une était âgée (75 cm LT). Il s’agit pour ces personnes, précédemment intoxiquées en septembre 2009, d’une légère rechute. Le deuxième cas repose sur l’intoxication très sévère mais non léthale d’un chaton qui a consommé de la chair d’un jeune lutjan (Lutjanus fulviflamma) de 18 cm LT. Ces deux cas incriminent d’une part un poisson âgé, et donc à risque, mais d’une espèce rarement ciguatoxique, et d’autre part un jeune poisson d’une espèce certes à risque, mais ayant forcément consommé au cours de sa courte vie, un nombre limité de proies porteuses de toxines. Ils conduisent à penser que la charge environnementale en organismes à l’origine de la production des toxines est potentiellement élevée en Baie de Prony, a minima dans certaines zones. Ces densités élevées, si elles sont avérées, pourraient être liées à un stress de l’environnement, notamment lié à la conduite de travaux lourds dans la zone à partir de 2004, dans le cadre de la mise en place du port de l’usine Goro-Nickel. Une recherche spécifique in situ de ces organismes permettrait de partiellement valider cette hypothèse, de même que la recherche de toxines sur des poissons résidents de la Baie.
Most arguments invoked so far by the scientific community in favour of shark conservation rely on the ecological importance of sharks, and have little impact on management policies. During a 57-month study, we were able to individually recognise 39 sicklefin lemon sharks that support a shark-feeding ecotourism activity in Moorea Island, French Polynesia. We calculated the direct global revenue generated by the provisioning site, based on the expenses of local and international divers. The total yearly revenue was around USD5.4 million and the 13 sharks most often observed at the site had an average contribution each of around USD316 699. Any one of these sharks represents a potential contribution of USD2.64 million during its life span. We argue that publicising economic values per individual will be more effective than general declarations about their ecological importance for convincing policy makers and fishers that a live shark is more valuable than a dead shark for the local economy. Studies monitoring the potential negative ecological effects of long-term feeding of sharks should, however, be conducted to ensure these are also considered. Besides declarations about the nonconsumptive direct-use value of sharks, as promoted by ecotourism, the calculation of their other economic values should also benefit shark conservation.
Les merveilles du monde animal composent le fantastique spectacle de la nature. On pense notamment à ces courtes périodes où des dizaines de milliers d’individus se rassemblent pour se nourrir, s’accoupler ou donner naissance à leurs petits. C’est le cas des vastes colonies d’oiseaux de mer en période de nidification, des nuées de papillons monarques, des migrations saisonnières des hordes de gnous, des amas de serpents entrelacés, de la ponte des tortues sur les plages, des aires de mise bas des requins ou des périples des oiseaux migrateurs. Pour beaucoup d’espèces, ces phénomènes biologiques sont essentiels à la régénération de la population. Aujourd’hui, l’importance de ces rassemblements biologiques de masse est largement reconnue et ils font souvent l’objet de mesures de protection lorsqu’ils se déroulent à terre. En effet, ils représentent pour la plupart une importante source de revenus touristiques.
Wildlife spectacles are marvels of nature. They can involve brief gatherings of tens of thousands of individuals for feeding, mating or giving birth. Examples include large nesting seabird colonies, enormous gatherings of monarch butterflies, seasonal mass movements of wildebeest, snake congregations, turtles on nesting beaches, shark birthing areas, and bird migrations. For many species, these are key life history events that are crucial for population regeneration. Today the importance of these massive biological gatherings is widely recognised, and many land-based events receive some protection. Indeed, many wildlife spectacles are now important generators of tourism dollars.
Le PROE et la CPS ont organisé sous l’égide du programme CRISP une campagne scientifique qui s’est déroulée aux récifs des Chesterfield entre le 6 et le 21 août 2010. Cette mission a permis aux 12 scientifiques (de 6 nationalités différentes) de décrire i) les principaux habitats coralliens, la diversité des coraux et leur état de santé, d’évaluer ii) les ressources en invertébrés benthiques, iii) en poissons récifaux d’intérêt commercial, iv) les populations de requins de récif, v) de mettre en œuvre une étude sur la connectivité des grands requins, vi) de réaliser un dénombrement des populations d’oiseaux marins nicheurs et d’évaluer le risque présenté par les rongeurs envahissants, et enfin vii) d’évaluer les populations de mammifères marins.
The SPREP and SPC organized under the auspices of the CRISP programme a scientific campaign to the Chesterfield reefs which took place between the 6th and 10th of August 2010. This survey allowed the 12 experts (from 6 different countries) to collect information related to i) the description and assessment of the health status of coral habitat, ii) the assessment of reef invertebrates and iii) fish resources, iv) coastal sharks populations and v) connectivity of large pelagic sharks, vi) nesting birds and rodent invasive species and vii) cetaceans.
Brunnschweiler & McKenzie (2010; Mar Ecol Prog Ser 420:283–284) expressed reservations over the findings of Clua et al. (2010; Mar Ecol Prog Ser 414:257–266), mostly related to the lack of a reference site or a control group in the methodology. In our study, we distinguished between 39 individuals of sicklefin lemon sharks Negaprion acutidens, mainly based on photo-identification. Our study was based on the field-survey approach, with time (a continuous variable) as the source of variation, and thus a control group was not necessary. We provide here additional data that support the notion that abundance of lemon sharks on the provisioning site was increasing, both in their number and fidelity. We maintain our conclusion that sicklefin lemon shark provisioning off Moorea Island can continue, but should be more intensely controlled.
PCC stands for postlarval capture and culture (or “growout”). Postlarvae are a development stage in reef fish and crustaceans prior to both settlement in the lagoon and adulthood. The vast majority of animals start their development cycle with an ocean phase lasting one to three months, after which fish and crustaceans re-enter the lagoon in their hundreds of millions. Only approximately one in a million individuals will reach their adult stage, with most juveniles being eaten by predators. Using innovative techniques (such as crest nets or light traps – see photos below), postlarvae can be captured and bred for sale to four potential uses: aquaculture for food purposes; restocking into ecosystems to boost biodiversity and fish density for fishing purposes or simply for ecotourism such as snorkelling in coral gardens; and the lucrative aquarium market. Despite their impressive numbers, the captured animals only account for a very small portion of the larval flow, hence the very slight impact on the ecosystem compared to techniques involving the capture of adults with large quantities of breeding individuals. This makes PCC a potentially ecofriendly industry.
Feeding wild animals is a common practice in the ecotourism industry. Operators do so both on land and under water to gather fauna at particular spots so that they can be viewed by tourists. Operators would otherwise be unable to guarantee their customers sightings of particular animals that are generally shy and reclusive. The practice is often controversial because although it has undeniable advantages for humans — discounting the inherent danger of attack by large predators — it involves potentially negative effects for wild animals. Shark feeding is no exception and much has been written on the issue, although, until recently no scientific studies were available, despite sharks being emblematic animals in the Pacific. The gap has now been filled with a project implemented jointly by the Secretariat of the Pacific Community (SPC) and the French Centre de recherche insulaire et Observatoire de l’environnement (CRIOBE) in Moorea, French Polynesia.
This leaflet presents 4 sucess stories of projects of sustainable reef fisheries that were supported by the Coral Reef InitiativeS for the Pacific (CRISP programme) implemented under the auspices of the Secretariat of the Pacific Community in Noumea.
The feeding of marine predators is a popular means by which tourists and tour operators can facilitate close observation and interaction with wildlife. Shark-feeding has become the most developed provisioning activity around the world, despite its controversial nature. Amongst other detrimental effects, the long-term aggregation of sharks can modify the natural behaviour of the animals, potentially increase their aggression toward humans, and favour inbreeding. During 949 diving surveys conducted over 44 mo, we investigated the ecology and residence patterns of 36 photoidentified adult sicklefin lemon sharks Negaprion acutidens. The group contained 20 females and 16 males. From this long-term survey, we identified 5 different behavioural groups that we described as ‘new sharks’ (7), ‘missing sharks’ (4), ‘resident sharks’ (13), ‘unpredictable sharks’ (5) and ‘ghost sharks’ (7). In spite of movements in and out of the area by some males and females, which were probably related to mating, the general trend was that residency significantly increased during the study, particularly in males, showing a risk of inbreeding due to the reduction of shark mobility. Intraand interspecific aggression was also witnessed, leading to an increased risk of potentially severe bites to humans. Our findings suggest the need for a revision of the legal framework of the provisioning activity in French Polynesia, which could include a yearly closure period to decrease shark behavioural modifications due to long-term shark-feeding activities.
Suite aux analyses des professionnels polynésiens de la filière PCC* et du service de la pêche, la capture d’espèces rares est apparue comme essentielle pour un développement durable de cette filière qui malgré des recherches en développement depuis 1995, n’est pas encore rentable. Dans ce contexte, une équipe de trois experts s’est rendue dans l’Île de Nuku Hiva (Archipel des Marquises) du 28 mai au 1er juin afin d’évaluer le potentiel d’exportation de poissons ornementaux aux stades de postlarves et, accessoirement, d’adultes. Quatre plongées et des discussions avec une personne ressource locale, cumulant 30 ans de plongée sur l’ensemble de l’archipel, aboutissent à la conclusion qu’une commercialisation d’espèces endémiques ou d’espèces à forte valeur commerciale avec des morphes de robe propres aux Marquises, pourrait s’avérer rentable. La capture de postlarves à l’aide de light-traps devrait permettre de commercialiser avantageusement les trois espèces d’Apogonidae qui constituent généralement un pourcentage important des prises de postlarves (PL) avec les engins de PCC. Elle pourrait être complémentée financièrement par la capture, a minima et dans des limites restant à déterminer et fixer légalement, des deux espèces d’Anthias endémiques, particulièrement denses et constituant les espèces les plus accessibles à une pêche en apnée comme l’impose la législation polynésienne.
The case of a fatal, unprovoked shark attack is reported and analyzed. The incident took place on the 30th of September 2007, in the lagoon of Luengoni Bay, Lifou Island (Loyalty Islands, New Caledonia). A young French woman who was snorkeling was severely bitten on the right thigh and died of hemorrhage. An analysis based in particular on the size and color of the shark, the characteristics of the wounds, and the behavior of the shark before and after the bite suggests that the aggressor was a great white shark, Carcharodon carcharias.
This study was conducted to determine whether ventilatory parameters would change in breath-hold divers (BHDs) after they performed the glossopharyngeal technique for lung insufflation. Fifteen elite BHDs, 16 non-expert BHDs and 15 control subjects participated in this cross-sectional study. Volumes and expiratory flow rates were measured twice, before and after the glossopharyngeal technique performed at rest. Before the technique, greater forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV(1)) and lower FEV(1)/FVC were noted in the elite and non-expert BHDs compared with controls. No difference was noted regarding the other pulmonary parameters. After the technique, increases were noted in FVC, FEV(1) and maximal voluntary ventilation in the elite BHDs (P < 0.001, respectively). The FEF(25-75%)/FVC ratios were lower in the BHDs both before and after the technique, indicating possible dysanapsis. The ventilatory parameters observed after the glossopharyngeal technique indicated (1) higher lung volumes in expert BHDs and (2) a correlation with BHD performance (maximal dynamic BH performance). This correlation became more significant after the technique, indicating a positive effect of glossopharyngeal insufflation on performance.
New Caledonia appears as a wintering ground for Great White Shark (Carcharodon carcharias) that arrive from the South around June in the track of humpback whales and leave around March. The feeding on deep spawning aggregations of snappers may explain why this species remains so long after the departure of whales in December. GWS are responsible for several fatal attacks on humans in New Caledonia, tha last ones taking place in 2007 and 2009.
How a cultural approach is necessary in the South Pacific to obtain a full ownership of stakeholders and efficiency in the framework of the implementation of Locally Managed Marine Areas?
A global analysis of the effects of climate change on fish stocks, fisheries and food security if conducted for the Pacific island and presented by Dr Eric CLUA from the Secretariat of the Pacific Community. After presenting the importance of fish in the oceanian diet, effects of CC on fish stocks is presented and solutions are drawn for the future.
Governments, non-government organizations, and other stakeholders are striving to develop practices, policies, and vehicles to make the tropical marine ornamental trade sustainable. Small-scale fisheries based on post-larval capture and culture (PCC) promise to contribute to this goal by (1) removing the risk of damaging corals (inherent in harvesting adults of target species established on reefs) by collecting post-larvae with light traps, nets, and purpose-built temporary shelters as they settle from the plankton to the substrate; and (2) translating the high mortality of post-larvae at settlement into high rates of survival in culture. Possible concerns about overfishing of post-larvae, harvesting the juveniles after they have run the gauntlet of predation at settlement, and the large proportion of bycatch can be eliminated or greatly alleviated by restricting the size and quantity of fishing gear, designing it to retain bycatch alive, and releasing bycatch at times and places that minimize predation. However, special caution is needed when PCC is used at small, isolated islands with self-replenishing populations. Although PCC is environmentally friendly, its contribution to the ornamental trade is expected to be limited. Large variation in the abundance and species composition of settling post-larvae among years, the logistics and costs of operating labor-intensive operations in remote locations, and competition with responsible enterprises harvesting wild adults or producing ornamentals in hatcheries are expected to constrain the viability and market share of dedicated PCC enterprises. PCC is expected to have the greatest uptake by part-time artisanal fishers in developing countries with infrastructure for exporting marine ornamentals. Such fishers are more immune to temporal variation in the supply of post-larvae—they can engage in PCC when valuable post-larvae are abundant and switch to other sources of income when they are scarce. Livelihood opportunities for smallholders could be enhanced through promotion of the environmental benefits of PCC among hobbyists maintaining marine ornamentals.
Shark feeding is a controversial recreational activity that may alter shark behaviour. In order to investigate possible behavioural changes at the level of the individual, it is necessary to recognise each shark underwater and in a nonintrusive way. In this study, we tested a protocol based on natural marks on fins, and coloured spots and scars on the body to differentiate individual sicklefin lemon sharks. We found that a feeding group, aggregated for 26 months at a northern location off Moorea Island, comprised 32 animals (19 females and 13 males), identified from 2589 observations made over 541 dives. Post-dive photo-identification of individual sharks was a reliable technique, whereas a high level of skill was required to ensure an instantaneous identification underwater. However, direct underwater identification of individual sharks can be of potential use in shark behavioural studies.
A major proportion of coral reefs around the world occur in small island developing countries (SIDS). The status of these resources is declining, while these countries simultaneously face major challenges in sustainable development for their people. Reef conservation in SIDS cannot be approached in the same way as conservation in more developed countries, even though the tools such as Marine Protected Areas may be effective for both situations. One of the main differences relies on the widespread inability of government services within SIDS to ensure adherence to legal frameworks aimed at protecting the reef resources from irreversible depletion. This gap can be compensated with a strong ownership by local communities through locally managed marine areas. The emergence of a real ownership strongly depends on the ability of developing actors in promoting the cultural dimension as a root of the process of locally based management which should include traditional tools, even if they need, most of the time, to be updated regarding ecological constraints for a sustainable development of reef resources. Therefore, a particular focus should be put by developing agencies on the integration of human factors (anthropology, socio-economics) for insuring the success of the ground actions, with innovative tools such as human factor based Geographic Information Systems. Local ownership can also be boosted by real examples of grounds successes to be shown to candidate communities and another issue relies on the setting up of functional networks at a regional level. The Coral Reef Initiative for the Pacific (CRISP) is a US$ 10 million programme over 3 years which implements this specific approach. The concepts behind CRISP draw on the recommendations of the International Coral Reef Initiative, and specifically seek to find Pacific solutions to regional problems
L’acronyme PCC provient de la terminologie anglophone Postlarvae Capture and Culture que l’on peut traduire par capture et culture des postlarves. Les postlarves sont un stade de développement des poissons et crustacés de récif qui précède l’installation dans le lagon et le passage au stade adulte. La grande majorité des animaux débutent leur cycle de développement par une phase océanique de 1 à 3 mois à l’issue de laquelle poissons et crustacés réinvestissent par centaines de millions les lagons. Environ un seul individu sur un million parviendra à l’état adulte, la plupart de ces juvéniles disparaissant dans l’estomac de prédateurs. Des techniques innovantes permettent de capturer ces postlarves pour les élever et les valoriser à travers trois destinations possibles : l’aquaculture pour produire des poissons de bouche, le réensemencement des écosystèmes pour renforcer la biodiversité et la densité des poissons (destinés à être pêchés ou simplement contemplés par les touristes) et enfin, le marché (rémunérateur) de l’aquariophilie. Malgré leur nombre impressionnant, les animaux capturés ne représentent qu’une portion très marginale du flux larvaire, d’où un impact très mesuré sur l’écosystème comparé à des techniques de capture des adultes qui sont des géniteurs en puissance. Ce point fait de la PCC une filière potentiellement ecofriendly (en terminologie anglo-saxonne). Afin de partager les expériences scientifiques et techniques acquises dans ce domaine ainsi que les perspectives qu’il offre en matière de développement durable et d’écocertification, le ministère des Affaires étrangères et européennes, l’Agence Française de Développement (AFD), le Fonds Français pour l’Environnement Mondial (FFEM), et l’Aquarium tropical du palais de la Porte Dorée se sont associés pour l’organisation d’un séminaire intitulé “Postlarves, commerce et développement” qui s’est tenu le mercredi 2 juillet 2008, à Paris. Cet événement, accueilli par l’Aquarium de la Porte Dorée, de 14 h à 17 h, au 293 av. Daumesnil – 75012 Paris, a rassemblé une quarantaine de personnes dont des professionnels, scientifiques, utilisateurs et institutions françaises impliqués dans le domaine. Les objectifs poursuivis par ce séminaire étaient les suivants : – Présenter les bases scientifiques du caractère “durable” des filières reposant sur la capture des postlarves; – Effectuer un bilan des expériences passées quant à la commercialisation de ces produits ecofriendly; – Informer les divers acteurs de la stratégie de développement des filières postlarves dans le Pacifique, notamment des aspects d’écocertification; – évaluer l’intérêt porté par les différents professionnels à ces produits dont la viabilité économique est intimement liée à un effort de promotion à tous les niveaux de la filière. Le séminaire a débuté techniquement par une présentation des aspects scientifiques et de l’impact écologique de la PCC par le Pr René Galzin (EPHE). Il ressort que cette technique a un impact écologique mineur, mais que sur le plan de la rentabilité économique elle est pénalisée par l’hétérogénéité temporelle des captures, la relative pauvreté en espèces à forte valeur commerciale, et parfois le coût de la main d’œuvre qui peut être rédhibitoire dans certains pays. La recherche scientifique appliquée actuelle se penche sur la valorisation des postlarves de crustacés, et le test de méthodes d’attraction (son, olfaction) visant de nouvelles espèces. La présentation suivante a été effectuée par Patrice Ortin de la société ALL Marine, qui a fait état de résultats encourageants pour l’installation de filières en Indonésie reposant sur l’utilisation de pièges lumineux, tout en insistant sur les difficultés à faire accepter “culturellement” ces nouvelles technologies, et à ne pas négliger d’autres techniques, notamment la capture de juvéniles dans les cuvettes à marée basse (dont l’impact écologique est néanmoins plus grand que la PCC). Gilles Lecaillon de la société Ecocean, a fait un bilan globalement positif des expériences conduites dans le Pacifique, l’Indo-Pacifique et la Méditerranée, en insistant sur la nécessité d’implication de tous les acteurs pour une réussite d’installation de ces filières à un niveau viable. Sébastien Bernis a fait état pour le compte de la chaîne de magasin Botanic, d’une expérience de commercialisation de postlarves qui a échoué mais qui mérite d’être renouvelée de façon plus professionnelle, étant donné les atouts de ces produits ecofriendly. Éric Clua, coordinateur du programme CRISP (InitiativeS Corail pour le Pacifique), portée par l’AFD, le FFEM et le MAEE, a conclu les présentations par la description des stratégies d’amélioration de l’offre en postlarves à l’échelle du Pacifique et de modification de la demande, notamment par la mise en place d’une écocertification. Le séminaire s’est conclu par un débat constructif dont il ressort une volonté claire des professionnels présents de contribuer au développement de filières commerciales reposant sur des postlarves, dès lors que ces produits répondront à des critères incontournables de qualité, sachant qu’ils bénéficient par ailleurs d’atouts indéniables pour convaincre un public de plus en plus sensible aux aspects de “responsabilité écologique” dès lors que l’on touche au commerce d’animaux.
The present paper analyzes data collected between 2001 and 2002 on 81 reef fish species targeted by fishers at 5 sites in the Kingdom of Tonga (South Pacific). We first ranked the sites with respect to fishing pressure using two independent methods: (i) Tongan demography and reef surfaces available for fishing, and (ii) the differential effects of fishing on the whole set of 81 species grouped by their life history traits (LHT). We then focused on Parrotfish (Scaridae), which are heavily targeted in coral reef fisheries. We used the identified gradient of fishing pressure to study the effect of fishing on the community structure and test the hypothesis of « shifting dominance » amongst the 20 Scarid species present in the surveys. In addition to the classical effect of decreasing fish size in a family strongly targeted by fishers, the shifting dominance phenomenon includes a decrease in the abundance of the large-bodied and highly targeted species, favouring their replacement by smaller-bodied species from the same family, which are less impacted by fishing. In a context of interspecific competition amongst Scarids, the stress of fishing appears as a factor favouring the replacement of species with large maximum size, and LHT promoting low resilience, by smaller species with the opposite attributes. The discussion focuses on the various processes that can explain the shifting dominance phenomenon. The total density of resilient species, which increased along the gradient of increasing fishing pressure, can be used as an indicator of the over-exploitation of fish communities for reef fisheries management.
L’intérêt de la pratique du yoga pour l’entraînement en apnée est indéniable du point de vue empirique mais il n’a été que partiellement démontré du point de vue scientifique. Au cours de ce chapitre, nous proposons de présenter dans un premier temps les principaux acquis scientifiques sur les vertueuses modifications induites par le yoga sur les paramètres physiques, physiologiques et psychiques de la performance en apnée. Nous abordons ensuite les rapports entre yoga et apnée sur un plan plus pratique en proposant des exercices couramment utilisés par les apnéistes adeptes de ces arts complémentaires. Nous présentons successivement des exercices empruntés au yoga postural (Hatha-yoga), à la science yogique de la respiration (prânayâma) ou encore à la relaxation. À chaque reprise sont indiqués les intérêts des exercices ainsi que les techniques de leur mise en œuvre. Un exemple de programme pré-compétition est enfin fourni à titre indicatif.
Après avoir passé en revue les grands principes de l’entraînement, ce chapitre se penche sur les spécificités liées à l’apnée. Il présente les facteurs contribuant à la performance en apnée : les facteurs anatomo-physiques, physiologiques, psychologiques et techniques. Ces facteurs sont étudiés en même temps que sont évoqués les exercices permettant leur amélioration. La troisième partie du chapitre présente les éléments permettant la structuration d’un entraînement à l’apnée, par le biais de nombreux exemples d’exercices. Après être revenu sur les composantes spécifiques à l’entraînement en apnée que sont la sécurité et les souffrances psychologiques et physiologiques, le chapitre propose ensuite une méthode d’entraînement répondant à toutes les contraintes évoquées au préalable. Cette méthode repose sur l’utilisation des « performances acquises » pour mener efficacement un entraînement collectif avec des niveaux hétérogènes chez les élèves. En conclusion, l’accent est mis sur les lacunes actuelles qui engagent à maintenir la sécurité comme une composante majeure de l’entraînement en apnée.
Direct effects of fishing pressure (FP) well documented in Reef ecosystems (Russ, 1991). Indirect effects much less documented, excepting a compensatory increase of density of small size individuals of the targeted species under low FP (Dulvy, 2004). Scarids: well represented species among the reef fisheries of the Pacific. HYPOTHESIS: The removal of Scarids by fishing has an obvious direct effect on the abundance of the targeted species, and also an indirect effect on the relative abundances of other Scarid species, including species not targeted by fishers.
Deux pêcheries ont été sélectionnées dans chacun des trois archipels des Tonga selon la pression de pêche (forte ou faible). Dans chacune, ont été conduites des enquêtes socio-économiques afin d’affiner l’évaluation de cette pression, pendant que les stocks de poissons récifaux étaient évalués par comptages visuels sous-marins sur 241 transects et leur habitat décrit par une méthode novatrice (à une échelle moyenne), mieux adaptée à leur territoire de vie. L’analyse des données écologiques et halieutiques a permis de montrer que les pressions de pêche globales divergeaient entre archipels et que, combinées aux facteurs écologiques, elles prenaient le pas sur les différences entre sites au sein des archipels. Le facteur pêche explique globalement moins de variance entre peuplements (entre 1,6 et 5,7%) que les facteurs œuvrant à une micro-échelle (tels que : profondeur, couverture en substrat dur et corail vivant, hétérogénéité et complexité topographique) et à une méso-échelle (influence océanique), qui expliquent entre 23,3 et 34,3%. L’étude a confirmé les effets déjà connus de la pêche sur la structuration des peuplements (réduction de la taille moyenne, augmentation compensatrice de la densité dans les classes de petite taille) et a montré l’existence, au moins pour la famille des Scaridae, d’une « transdominance d’espèces », reposant sur la perte de dominance d’espèces cibles de tailles maximales importantes au bénéfice d’espèces de tailles maximales réduites, moins sensibles à la pression de pêche. Le regroupement des espèces par régimes alimentaires ou traits de vie a permis de révéler un changement graduel dans les densités et biomasses relatives de certains groupes en fonction du gradient de pression de pêche. Ce phénomène permet d’envisager l’élaboration d’indicateurs de l’état des stocks pouvant contribuer à une meilleure gestion des ressources en poissons récifaux.
Sharks are found throughout the world in a wide variety of habitats and developed different life histories traits. Though sharks make up only a small percentage of the world’s recorded fish landings, they are extremely versatile and are a valuable resource. They are of primary importance in some regions of the world, sustaining important fisheries in some countries. Moreover, they have been, and are, a cheap but valuable source of protein for coastal communities dependent on subsistence fisheries. Humans can utilize much of the carcass for food or other uses. Sharks are exploited for their meat, fins, skin, liver, teeth, cartilage and other internal organs. Sharks are increasingly becoming endangered on a world-wide scale. The main reason for this is the demand for their fins which are being used for shark fin soup, an Asian delicacy. The extermination of Asian shark stocks has led to an increase in the price of the fins and this in turn has led Asian fishing operators to target sharks further and further away from their home countries, including the Pacific region. It has also contributed to the development of specific fisheries whereas elasmobranchs were so far essentially by-catches. From the point of view of Fisheries Departments of the Pacific countries, fishing pressure on reef sharks is not high, although no data is available for most of these countries. Assessment of the information collected through literature and questionnaires shows that Pacific shark catches seem to be poorly documented. This bibliographic study enhances the need for rapid assessment techniques using biological information to evaluate the risk from the effects of fishing on shark conservation.
Nombre de démarches actuelles visant à impliquer les acteurs locaux dans la gestion des ressources naturelles reposent sur des présupposés qui faussent une collaboration potentiellement efficace entre populations locales et institutions en charge de la mise en place de dynamiques de co-gestion durable de ces ressources. Les sociétés insulaires du Pacifique sont communément décrites sous un angle simpliste les présentant comme homogènes et culturellement en harmonie avec leur milieu. Cette vision qui renvoie au mythe du « bon sauvage » directement hérité du siècle des lumières, est réactualisée par les organisations internationales sous la dénomination galvaudée de « communautés locales ». Leur état de « nature » leur confèrerait d’emblée une sagesse et un savoir-faire adaptés à une gestion durable de leurs ressources qui implique une conception de la gouvernance se résumant à un simple transfert de compétences décentralisées. Or les sociétés insulaires locales sont hétérogènes, dynamiques et contemporaines. Hétérogènes car constituées de groupes sociaux en perpétuelle concurrence. Dynamiques car en mutation rapide à l’heure actuelle. Contemporaines car, loin de vivre repliées sur elles-mêmes, elles montrent une propension importante à internaliser toutes les opportunités qui permettent d’agir dans le jeu social local : instrumentalisation des projets de développement et des positions administratives, utilisation des réseaux religieux et politiques, recours aux technologies modernes, etc. Les villages ou tribus océaniens sont des constructions coloniales de groupes sociaux différents rassemblés autour d’un lieu de culte (église ou temple). Ces groupes sociaux appartiennent en fait à des organisations en réseaux coutumiers répartis dans plusieurs villages. Cette caractéristique est la base d’un jeu local éminemment complexe mêlant les allégeances et alliances coutumières, les influences religieuses et les opportunités qu’offrent la politique et l’organisation administrative locale ou territoriale. Face à cette complexité, les processus de gestion intégrée doivent s’appuyer sur une conception moins naïve et plus pragmatique de la gouvernance, reposant sur une compréhension plus approfondie des stratégies d’acteurs permettant une meilleure adaptation des outils et une réelle interaction entre acteurs locaux et acteurs institutionnels. Le programme CRISP1 cherche à développer cette conception de la gouvernance en matière de gestion côtière intégrée dans laquelle les populations locales doivent jouer un rôle « négocié » prenant mieux en compte les fondements de leur organisation culturelle. A cet effet, le projet GERSA2, mis en œuvre par l’Unité ESPACE3 de l’IRD, joue un rôle transversal dans la composante 1 du CRISP qui englobe la gestion d’Aires Marines Protégées. L’analyse approfondie des sociétés locales sous les angles de la géographie culturelle et de la socio-économie est pleinement intégrée à la mise en œuvre d’outils opérationnels garantissant l’implication totale des acteurs locaux dans tout le processus de gestion, y compris les processus techniques. Cette démarche répond à la prise de conscience que la conservation de la nature ne peut être dissociée de la prise en compte de facteurs tels que la représentation culturelle que les usagers en ont et les enjeux d’usage dont elle fait l’objet.
Habitat characteristics play a critical role in structuring reef fish communities subjected to fishing pressure. The line intercept transect (LIT) method provides an accurate quantitative description of the habitat, but in a very narrow corridor less than 1 m wide. Such a scale is poorly adapted to the wide-ranging species that account for a significant part of these assemblages. We developed an easy-to-use medium scale approach (MSA), based on a semi-quantitative description of 20 quadrats of 25 m2 (500 m2 in total). We then simulated virtual reef landscapes of different complexities in a computer, on which we computed MSA using different methods of calculation. These simulations allowed us to select the best method of calculation, obtaining quantitative estimates with acceptable accuracy (comparison with the original simulated landscapes: R2 ranging from 0.986 to 0.997); they also showed that MSA is a more efficient estimator than LIT, generating percentage coverage estimates that are less variable. A mensurative experiment based on thirty 50-m transects, conducted by three teams of two divers, was used to empirically compare the two estimators and assess their ability to predict fish–habitat relationships. Three-factor multivariate ANOVAs (Teams, Reef, Methods) revealed again that LIT produced habitat composition estimates that were more variable than MSA. Canonical analyses conducted on fish biomass data successively aggregated by mobility patterns, trophic groups, and size classes, showed the higher predictive power of MSA habitat data over LIT. The MSA enriches the toolbox of methods available for reef habitat description at intermediate scale (< 1000 m2), between the scale where LIT is appropriate (< 100 m2) and the landscape approach (> 1000 m2).
A major proportion of coral reefs around the world occur in developing countries. The status of these resources is declining, while these countries simultaneously face major challenges in sustainable development for their people. Reef conservation in SIDS cannot be approached in the same way as conservation in more developed countries, such as Australia or French territories, even though the tools such as Marine Protected Areas (MPA) may be effective for both situations. One of the main differences relies on the widespread inability of government services within SIDS to ensure adherence to legal frameworks aimed at protecting the reef resources from irreversible depletion. The Government of France has invited a wide range of other agencies (South Pacific Regional Environment Programme, Conservation International, WWF, United Nations Foundation and several scientific agencies) to join in developing a programme to address the root causes of coral reef degradation in South Pacific countries. This US$ 10 million project over 3 years will address a series of issues indicated by Pacific countries, with an emphasis on MPA implementation, integrated coastal management, development of coral reef resources (aquarium trade, ecotourism, marine active substances), rehabilitation of coral reef ecosystems and setting up of a regional reef database. A particular focus will be put on the integration of human factors (anthropology, socio-economics) for insuring the success of the actions developed on the ground, but also in the wide dissemination of the project outputs at a regional level. The integrated approach will rely on the dual involvement of land and marine issues, protection and development issues, community based and highest institutional level issues, existing tools (such as MPAs) and innovative ones (such as environmental information systems EIS, including human and cultural factors). The project will be focussed in Fiji, Vanuatu, Samoa, Cook Islands, Kiribati, French Polynesia, Wallis and Futuna and New Caledonia with the active involvement of other Pacific countries (Papua New Guinea, Niue, Tuvalu). The concepts behind CRISP draw on the recommendations of the International Coral Reef Initiative and partners, ICRAN (International Coral Reef Action Network) and GCRMN (Global Coral Reef Monitoring Network) and specifically seek to find Pacific solutions to regional problems.
The diversity of reef ecosystems, the multiplicity of reef resource uses and the breadth of the range of the island socio-cultural contexts concerned make coral reef fisheries (CRF) management in the South Pacific a complex task. The health and state of the targeted resources depend both on ecosystem characteristics (as determined by ecological and biological factors) and on fishing pressure, whose effects are only partly known. Increasing harvests from commercial and recreational fishing increasingly overlap with traditional Subsistence activity, creating an important CRF management challenge. This paper presents a new approach to CRF assessment and monitoring by providing a set of multidisciplinary indicators. The fisheries system is assessed from three different viewpoints: ecology of targeted populations, exploitation and the broader socio-econornic fishery context. The use of complementary indicators chosen from each of these fields could balance the chronic lack of human and financial resources for the management of these fisheries. We suggest the use of these indicators through an assessment grid or an indicator dashboard specifically adapted to given situations and management objectives determined through a participatory approach. The operational efficiency of this dashboard depends on i) dialogue between users, ii) the objectivity of the proposed monitoring, iii) the Visual transcription of divergent/convergent interests amongst stakeholders, and iv) stakeholder involvement in the decision-making process. The use and constraints of such a tool are described with reference to Ouvea atoll (New-Caledonia, South Pacific) for which an analysis of available indicators for assessing fisheries status is presented.
Deux pêcheries ont été sélectionnées dans chacun des trois archipels des Tonga selon la pression de pêche (forte ou faible). Dans chacune, ont été conduites des enquêtes socio-économiques afin d’affiner l’évaluation de cette pression, pendant que les stocks de poissons récifaux étaient évalués par comptages visuels sous-marins sur 241 transects et leur habitat décrit par une méthode novatrice (à une échelle moyenne), mieux adaptée à leur territoire de vie. L’analyse des données écologiques et halieutiques a permis de montrer que les pressions de pêche globales divergeaient entre archipels et que, combinées aux facteurs écologiques, elles prenaient le pas sur les différences entre sites au sein des archipels. Le facteur pêche explique globalement moins de variance entre peuplements (entre 1,6 et 5,7%) que les facteurs œuvrant à une micro-échelle (tels que : profondeur, couverture en substrat dur et corail vivant, hétérogénéité et complexité topographique) et à une méso-échelle (influence océanique), qui expliquent entre 23,3 et 34,3%. L’étude a confirmé les effets déjà connus de la pêche sur la structuration des peuplements (réduction de la taille moyenne, augmentation compensatrice de la densité dans les classes de petite taille) et a montré l’existence, au moins pour la famille des Scaridae, d’une « transdominance d’espèces », reposant sur la perte de dominance d’espèces cibles de tailles maximales importantes au bénéfice d’espèces de tailles maximales réduites, moins sensibles à la pression de pêche. Le regroupement des espèces par régimes alimentaires ou traits de vie a permis de révéler un changement graduel dans les densités et biomasses relatives de certains groupes en fonction du gradient de pression de pêche. Ce phénomène permet d’envisager l’élaboration d’indicateurs de l’état des stocks pouvant contribuer à une meilleure gestion des ressources en poissons récifaux.
This paper presents the first record of a blue whale (Balaenoptera musculus) in New Caledonia, south-west Pacific. The individual observed was a juvenile male. It spent more than a month in the shallow waters of the lagoon of New Caledonia, during which its condition appeared to slowly deteriorate, until it was attacked and eaten by sharks.
This paper aims at investigating the effects of population pressure, westernisation- urbanisation and marine tenure systems on the status of reef finfish resources in two South Pacific countries. Finfish resource, total catch and per capita fresh fish consumption decreased with increasing westernisation-urbanisation, supporting a direct link between fishing and population pressure. Unconventionally, we suggest that in the communities surveyed the interest for fish consumption and fisheries diminishes with increased westernisation-urbanisation due to the available nutrition and income alternatives. Significant variations of fishing levels suggest that the level of exploitation is the predominant factor in structuring fish populations observed. Fishing pressure was found to initially affects biomass through size, and then density. Findings indicate a direct relationship between resource status and user level. Because marketing may be more influential than marine property systems, the final decision to which marine tenure systems add to urbanisation-westernisation influences to fishing pressure and thus status of reef fish needs further analysis.
A checklist is given below of 1162 species of shore and epipelagic fishes belonging to 111 families that occur in the islands of Tonga, South Pacifie Ocean; 40 of these are epipelagic species. As might be expected, the fish fauna of Tonga is most similar to those of Samoa and Fiji; at least 658 species of the fishes found in Tonga are also known from Fiji and the islands of Samoa. Twelve species of shore fishes are presently known only from Tonga. Specimens of Tongan fishes are housed mainly in the fish collections of the National Museum of Natural History, Washington D.C.; Bernice P. Bishop Museum, Honolulu; Museum National d’Histoire Naturelle, Paris; and the Australian Museum, Sydney. Native Tongan names of fishes, when known, are presented after species names.
L’auteur a suivi le séjour de 3 semaines d’un juvenile mâle de baleine bleue Balenoptera musculus brevicauda qui s’est réfugié en janvier 2002 dans une baie du Sud de la Nouvelle-Calédonie où son état général s’est progressivement dégradé jusqu’à ce qu’il soit attaqué et tué par des requins bouledogues Carcharhinus leucas. Le cadavre de l’animal a été ensuite dévoré par une agrégation (> 40) de requins tigres Galeocerdo cuvier.
Un indicateur de l’évolution et de l’impact d’une pression de pêche, reposant sur le suivi d’une espèce ou d’un groupe d’espèces de poissons, doit répondre aux exigences suivantes 1) Simplicité : ne nécessitant pas un recueil de données complexes; 2) Fiabilité : corrélation forte entre les paramètres de la population suivie et le facteur de perturbation; 3) Robustesse : variations des paramètres de la population suivie dépendant essentiellement du facteur de perturbation; 4) Facilité de mise en œuvre : recueil de données in situ pouvant être effectué par des acteurs non experts. L’analyse statistique des données issues de deux campagnes de comptages visuels sous-marins (CVS) en Nouvelle-Calédonie, respectivement en Province Nord (885 transects de 50 mètres de long) et Lagon sud-ouest (400 transects de 100 mètres de long), a permis l’identification d’une espèce, la saumonée Plectropomus leopardus (Serranidae) dont les paramètres de population (densité, biomasse) semblent intimement corrélés à la pression de pêche. Faute de données précises et fiables, celle dernière est évaluée indirectement pour les besoins de l’analyse. Si cet indicateur paraît relativement robuste, ses populations dépendent aussi des aléas du recrutement. L’analyse statistique n’a pas permis à ce jour l’identification d’autres espèces co-indicatrices de la pression de pêche, dont le suivi permettrait de nuancer les résultats sur les saumonées, afin notamment de s’affranchir des aléas de recrutement. Des pistes sont évoquées. Il est proposé de profiter de l’installation d’un nouveau centre minier à Koniambo (Province Nord), synonyme d’augmentation localisée de la pression de pêche, pour mettre en place un suivi expérimental qui permettrait de valider ces premiers résultats et d’affiner le rôle d’indicateur de la saumonée.
Each summer the presence of large concentrations of bait fish in the area of the central Azores Islands gives rise to mixed-species feeding aggregations usually at dawn and dusk. The encircling of prey initiated by common dolphins (Delphinus delphis), often mixed with spotted dolphins (Stenella frontalis), results in the formation of a compact ‘ball’ of several thousands prey fish close to the surface. Other dolphins, in particular the bottlenose (Tursiops truncatus), also eat the prey fish, whose high concentration makes them easy to capture. Large tunas (Thunnus thynnus, Thunnus albacares) sometimes participate in the phenomenon. Seabirds (mainly cory’s sheawaters, Calonectris diomedea borealis) are always present throughout the few minutes during which the entire collective food hunt takes place. A model of the phenomenon, based on 15 observations, is proposed. It comprises 4 stages: a preparation phase, an intensification phase, a mature phase, and a dispersion phase. These observations allow a better understanding of the tuna-dolphin aggregation process. They show that it is the tunas that generate and beneficiate from the aggregation with dolphins, rather than the contrary.
Cette étude, sensée contribuer à une meilleure connaissance des poissons fréquentant les substrats durs côtiers en Mauritanie, s’était fixée un double objectif : – d’une part découvrir de nouvelles espèces non encore répertoriées sur la zone ; – d’autre part vérifier des hypothèses d’interface originale entre espèces de poissons présentant des écologies différentes. Ce double objectif est rempli : – trois, voire quatre, espèces de poissons non encore citées dans la bibliographie ont été identifiées ; – des espèces de poissons appartenant à la même famille, et dont les écologies divergent, ont été répertoriées sur la zone d’étude. Le temps a fait cruellement défaut au cours de cette étude pour mener à bien les observations de terrain. Une restriction du domaine d’étude, soit à une zone plus précise (par ex. le substrat dur entre 0 et 2 mètres, ermettant de conserver une visibilité acceptable à chaque sortie), soit à certaines espèces au statut mal connu aurait peut-être permis une contribution plus approfondie et intéressante à la connaissance de la biologie des poissons ouestafricains. A ce titre certaines pistes d’investigation intéressantes pourraient être : – une étude approfondie des micro-espèces type Blennidae et Clinidae qui fréquentent le substrat dur entre 0 et 2 mètres ; – une étude spécifique sur les Scaridae dont les espèces présentes et la répartition sont loin d’être maîtrisées. Le cas du Sparisoma sp. de Tafarit en est une démonstration évidente ; – une étude spécifique sur le Scaridae de l’espèce Nicholsina usta dont le statut n’est pas définitivement arrêté, de même que ses liens de parenté avec l’espèce Cryptotomus rosaeus (citée par Maigret, 1986) ; – une étude spécifique sur les raies du genre Dasysatis sp. qui présentent un phénotype proche ou semblable à celui de pastinaca, sans forcément appartenir à cette espèce. Force est donc de reconnaître que le travail effectué reste très parcellaire, mais il n’en demeure pas moins une humble contribution au recensement de la biodiversité marine de la Mauritanie, et en particulier de celle du Parc National du Banc d’Arguin, pour laquelle, et ce jusqu’à l’heure actuelle, les velléités de protection relèvent essentiellement du principe de précaution et non pas, comme on serait en droit de l’attendre après plus de 20 ans d’existence, sur une connaissance approfondie de cette biodiversité et du capital inestimable qu’elle représente.
Nous vous proposons de présenter dans ces pages, une suite de récapitulatifs concernant le degré d’avancement des diverses disciplines naturalistes dans les pays de l’Ouest saharien. Cette série d’états de la question aura essentiellement pour objet de fournir – sous forme, entre autres, d’une bibliographie aussi complète que possible – d’indispensables outils de travail faisant, aujourd’hui encore, cruellement défaut.