Blue water, white tips
Oceanic whitetip sharks are formidable predators that have carved out a niche in the open ocean where prey is scarce. Once plentiful, they are now in serious trouble, but Demian has discovered an aggregation site that represents hope for one of the boldest fish in the ocean.
Demian Chapman
As a molecular ecologist at Florida International University, I am the leader of the Global FinPrint Project, the world’s largest reef shark and ray survey, which has recently drawn attention to the dire state of many sharks that live in tropical coastal areas and highlighted a portfolio of potentially effective conservation measures. Although I study live sharks and rays all over the world, I also track dead sharks and rays through my studies of the dried shark-fin trade in South-East Asia. These surveys have been informative in decision-making about which species to seek international trade regulations...
Tracking critically endangered oceanic whitetip sharks for effective transboundary conservation
The scientific aim of the project is to track the movements of oceanic whitetip sharks tagged in The Bahamas Shark Sanctuary in relation to protected areas and potential threats. The conservation aim of the project is to provide this information to key national and international policy-makers.
Determining how much time these critically endangered sharks spend in The Bahamas, where they are protected by a longline ban and recently established shark sanctuary, relative to time spent in international waters or the exclusive economic zones (EEZ) of other countries where they are exposed to commercial fisheries.
Elasmobranchs are apex predators and vital components of healthy and functional marine ecosystems, and they play key roles in structuring fish communities and fostering reef resilience. Their populations, however, are in decline due to low intrinsic rates of population increase paired with high-impact anthropogenic threats. Quantifying declines has been difficult, particularly in the Caribbean, due to a lack of fishery-independent data for assessing the condition of the stocks. Information on elasmobranch diversity, abundance and distribution, current exploitation levels and value, habitat use, and movement throughout their lifecycle remains sparse, especially in tropical countries such as Cuba. While Cuba still possesses much of the habitat considered essential for elasmobranchs, diversity, distribution and relative abundance and spatial ecology are relatively unknown. Neither Cuba nor its network of 118 MPAs feature legislation specifically related to the management of elasmobranchs, and the country has not yet produced a national plan of action (NPOA) for sharks.
One of the healthiest reefs is encompassed by the Jardines de la Reina MPA. Located in southern Cuba, this remote archipelago encompasses a broad range of habitats that host high faunal diversity and abundance. The benefits of MPAs for highly mobile species have yet to be fully characterised, with some sites providing insufficient protection for sharks.
Assessing the use of MPAs to protect sharks in relatively remote areas where fishing pressure is still minimal is important to understand whether MPAs are effective shark conservation tools. Jardines de la Reina MPA hosts several economically important species of elasmobranchs, notably silky sharks Carcharhinus falciformis, the most common species in shark by-catch in the US pelagic longline fishery, commonly landed in Mexico’s Atlantic coast and Cuba. Caribbean reef sharks can also be found at Jardines de la Reina MPA and they are economically important throughout the Caribbean for tourism. Jardines de la Reina MPA also hosts a little-known aggregation of spinner sharks (C. brevipinna) and anecdotally, occurrences of the Endangered great hammerhead Sphyrna mokarran have been registered. Aside from the Caribbean reef shark, very little is known about the behaviour, movement and habitat use of the three other focal species. Silky sharks and Caribbean reef sharks are further ranked as among the most important attractions for visitors to Jardines de la Reina MPA.
This project will contribute significantly to the currently small pool of knowledge for at least three poorly known species of elasmobranchs. It will further use conventional, acoustic and satellite tagging to assess the effectiveness of the Jardines de la Reina MPA in protecting the target species of sharks, as well as raise awareness for sharks and the MPA. Finally, this project aims to provide a proof of concept for replication of the project to other Cuban MPAs and create the enabling framework for both shark-friendly legislation and a NPOA for sharks.
- Fit 30 oceanic whitetip sharks with PSATs in spring 2012 off Cat Island, Bahamas.
- Determine whether tagged females are pregnant using an ultrasound.
- Produce definitive publications on the movements and habitat use of this species, including an assessment of where key breeding grounds are located and whether sharks that live in relative safety in The Bahamas Shark Sanctuary for most of the year are exposed to fisheries when they leave to breed.
- Provide publications and data to key policymakers in The Bahamas, in the US and that are part of ICCAT.