Field trip 2014 for shark research in Moorea

Projects funded by Save Our Seas Foundation and conducted by Johann Mourier from CRIOBE and Jeremy Kiszka from Florida International University.

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1rst Project: Using drones to investigate abundance of sharks and rays in shallow water habitats (PI: Johann Mourier)

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Accurately estimating shark abundance is critical to monitor population trends and adopt management measures if necessary. Several existing tools have been used to estimate elasmobranch abundance, including mark-recapture analyses based on fishing methods, underwater visual censuses (counts, photo-identification surveys) and, at larger spatial scales, aerial surveys. While all these techniques showed their efficiency to provide relative abundance estimates, they are not suitable to survey shallow water habitats, including shark nursery grounds, or they use invasive methods (fishing). The rapid technological advances now offer the development of easy and cheap methods to potentially monitor population abundance and trends. Here we aim to use drones equipped by video camera, altimeter and GPS devices to investigate abundance of elasmobranchs in lagoons of Moorea, French Polynesia. Ultimately, we aim to produce detailed guidelines based on distance sampling methods estimate absolute abundances of elasmobranchs in shallow water habitats.

 

2nd Project: Impact of shark provisioning on the ecology of lemon sharks at Moorea (French Polynesia) (PI: Jeremy Kiszka)

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Shark provisioning is a common practice around the globe. However, it affects shark behavior and populations at multiple scales, including habitat use and site fidelity patterns and increased population densities. Around the French Polynesian island of Moorea, shark provisioning is a significant source of incomes but induces strong behavioral modifications of sicklefin lemon sharks Negaprion acutidens. The goal of this project is to investigate the effect of shark provisioning on the diet, habitat use and aggregative behavior of lemon sharks. First, we will quantify the effect of provisioning on the trophic ecology of sharks using stable isotope analyses to assess how much shark diet comes from provisioning. Second, we will investigate the effect of provisioning on lemon shark habitat use, density and behavior using passive video recording. This project will contribute to better understand the ecological effects of shark provisioning at multiple scales on this vulnerable species.

 

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