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Other Scientists

Assistant Prof.
Aaron Carlisle
PhD Student
Nicholas Dunn
Dr.
Francesco Ferretti
Research Scientist
Robert Schallert
Dr.
David Jacoby
Species Distribution and Ecology

The Importance of the Chagos Archipelago for Pelagic Predators in the Indian Ocean

Principal Investigators
Prof.
Barbara Block
Dr.
David Curnick
Other Scientists

Project Overview

Context

Key focal species include:

Yellowfin tuna (Thunnus albacares; IUCN Status: Near Threatened),
Shortfin mako (Isurus oxyrinchus; IUCN Status: Vulnerable),
Scalloped hammerhead (Sphyrna lewini; IUCN Status: Endangered),
Silky shark (Carcharhinus falciformis; IUCN Status: Vulnerable),
Bigeye thresher (Alopias superciliosus; IUCN Status: Vulnerable),
Pelagic thresher sharks (Alopias pelagicus; IUCN Status: Vulnerable).

Funded by

The aim of our research is to provide an accurate representation of how the British Indian Ocean Territory’s (BIOT) Marine Protected Area (MPA) protects key species of pelagic predators.

Apex predators are crucial as regulators of our oceans and indicators of a healthy ecosystem. Top predators such as tunas and sharks, most of which are threatened with extinction, are under increasing pressure from fisheries, energy extraction and climate change. Moreover, we have a very limited understanding of their population ecology which in turn hinders our ability to manage them effectively.

Recently, MPAs have been increasing both in number and size but only a few empirical studies have investigated their effectiveness and use for protecting its highly mobile pelagic predators. To address this question, we are running a three-year research interdisciplinary programme combining biologging, chemical tracer analysis (stable isotopes and genomics), applied fisheries science and oceanography. We hope the collected data will allow us to better understand where and when such pelagic predators aggregate within BIOT, how connected BIOT’s community is with the wider Indian Ocean and how efficient is its MPA as a management strategy for pelagic predators of the Indian Ocean.

Our belief is that this endeavor will help understand the role of the BIOT MPA plays in the ecology of pelagic predators within the Indian Ocean and shed light on its potential to conserve these crucial species.

Yellowfin tuna is classified as 'Overfished and Subject to Overfishing' in the Indian Ocean by the Indian Ocean Tuna Commission. We need urgent action to stabilise its population.

David Curnick

Key Facts

55%
of the ocean is covered by industrial fishing
28
species of sharks and rays are found in BIOT
100
electronic tags were deployed on tuna and pelagic sharks
  • Grey reef shark, Carcharhinus amblyrhynchos.
  • Reef manta ray (Mobula alfredi) passing a school of fish, Egmont islands.
  • Grey reef sharks (Carcharhinus amblyrhynchos) swimming.
  • Reef manta ray (Mobula alfredi), Egmont islands.
  • Grey reef shark, Carcharhinus amblyrhynchos.
  • Grey reef shark, Carcharhinus amblyrhynchos.
  • Reef manta ray (Mobula alfredi) seen from under.
  • Tawny eyes nurse shark, Nebrius ferrugineus. Often called sleepy shark

Publications

Pop-up Archival Tags Reveal Environmental Influences on the Vertical Movements of Silvertip Sharks (Carcharhinus albimarginatus)

Tickler, D.M., Carlisle, A.B., Meeuwig, J.J., Chapple, T.K., Curnick, D., Dale, J.J., Castleton, M.J., Schallert, R.J., Block, B.B. (2023). Pop-up archival tags reveal environmental influences on the vertical movements of silvertip sharks (Carcharhinus albimarginatus). Marine Ecological Progress Series.

Environmental DNA Helps Reveal Reef Shark Distribution Across a Remote Archipelago

Dunn, N., Curnick, D.J., Carbone, C., Carlisle, A.B., Chapple, T.K., Dowell, R., Ferretti, F., Jacoby, D.M.P., Schallert, R.J., Steyaert, M., Tickler, D.M., Williamson, M.J., Block, B.A., Savolainen, V. (2023). Environmental DNA helps reveal reef shark distribution across a remote archipelago. Ecological Indicators.

Environmental DNA Reveals the Diversity and Abundance of Sharks and Rays in a Remote Coral Reef Atoll

Dunn, N., Savolainen, V., Weber, S., Andrzejaczek, S., Carbone, C., Curnick, D. (2022). Environmental DNA reveals the diversity and abundance of sharks and rays in a remote coral reef atoll. Molecular Ecology. Zoological Society of the Linnean Society.

Emergent research and priorities for shark and ray conservation.

Jorgensen, S.J., Micheli, F., White, T.D., Van Houtan, K.S., Alfaro-Shigueto, J., Andrzejaczek, S., Arnoldi, N.S., Baum, J.K., Block, B., Britten, G.L., Butner, C., Caballero, S., Cardeñosa, D., Chapple, T.K., Clarke, S., Cortés, E., Dulvy, N.K., Fowler, S., Gallagher, A.J., Gilman, E., Godley, B.J., Graham, R.T., Hammerschlag, N., Harry, A.V., Heithaus, M.R., Hutchinson, M., Huveneers, C., Lowe, C.G., Lucifora, L.O., MacKeracher, T., Mangel, J.C., Martins, A.P.B., McCauley, D.J., McClenachan, L., Mull, C., Natanson, L.J., Pauly, D., Pazmiño, D.A., Pistevos, J.C.A., Queiroz, N., Roff, G., Shea, B.D., Simpfendorfer, C.A., Sims, D.W., Ward-Paige, C., Worm, B., Ferretti, F., (2022) Emergent research and priorities for shark and ray conservation. Endangered Species Research. 

Behavior and Ecology of Silky Sharks Around the Chagos Archipelago and Evidence of Indian Ocean Wide Movement

Curnick, D.J., Andrzejaczek, S., Jacoby, D.M.P., Coffey, D.M., Carlisle, A.B., Chapple, T.K., Ferretti, F., Schallert, R.J., White, T., Block, B.A., Koldewey, H.J. and Collen, B. (2020) Behavior and Ecology of Silky Sharks Around the Chagos Archipelago and Evidence of Indian Ocean Wide Movement. Frontiers in Marine Science.

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