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L'objectif de l'étude est de proposer un cadre juridique propice à la biosécurité de Wallis et Futuna, qui réinvestisse les dispositions préexistantes en les étoffant et les renforçant. Cela répond à un contexte où les textes relatifs à la biosécurité de Wallis-et-Futuna étais épars, hétérogènes et en partie obsolètes. Les enjeux de biosécurité poussent à la réflexion vers un corpus complet, cohérent et actualisé en la matière. Le droit international et régional, notamment les directives de Port-Moresby de 2007, permettent d’alimenter la réflexion en la matière. Pour réaliser cette proposition ont été réalisés : (i) des entretiens, (ii) des analyses bibliographiques et synthèses de doctrine, de droit comparé, de droit régional, de droit international, proposition légistique et (iii) des analyses bibliographiques, propositions de listes et de fiches techniques.

ABSTRACT: Coastal fish populations are typically threatened by multiple human activities, including fishing pressure and run-off of terrestrial pollution. Linking multiple threats to their impacts on fish populations is challenging because the threats may influence a species directly, or indirectly, via its habitats and its interactions with other species. Here we examine spatial variation in abundance of coral reef fish across gradients of fishing pressure and turbidity in Fiji. We explicitly account for multiple pathways of influence to test the alternative hypotheses that (1) habitat moderates predation by providing shelter, so habitat loss only affects prey fish populations if there are abundant predators, (2) habitat change co-drives biomass of both prey and predator functional groups. We examined responses of 7 fish functional groups and found that habitat change co-drives both predator and prey responses to turbidity. Abundances of all functional groups were associated with changes in habitat cover; however, the responses of their habitats to turbidity were mixed. Planktivore and piscivore abundance were lower in areas of high turbidity, because cover of their preferred habitats was lower. Invertivore, browser and grazer abundance did not change strongly over the turbidity gradient, because different components of their habitats exhibited both increases and decreases with turbidity. The effects of turbidity on fish populations were minor in areas where fish populations were already depleted by fishing. These findings suggest that terrestrial run-off modifies the composition of reef fish communities indirectly by affecting the benthic habitats that reef fish use.

Sharks are considered the apex predator of coral reefs, but the consequences of their global depletion are uncertain. Here we explore the ecological roles of sharks on coral reefs and, conversely, the importance of reefs for sharks. We find that most reef-associated shark species do not act as apex predators but instead function as mesopredators along with a diverse group of reef fish. While sharks perform important direct and indirect ecological roles, the evidence to support hypothesised shark-driven trophic cascades that benefit corals is weak and equivocal. Coral reefs provide some functional benefits to sharks, but sharks do not appear to favour healthier reef environments. Restoring populations of sharks is important and can yet deliver ecological surprise.

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