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Scientists launch global shark and ray census

  • Scientists estimate that each year, up to 73 million sharks have their fins sliced off to make shark fin soup — a Chinese delicacy.
  • A growing appetite for shark fins and meat is considered the leading cause of sharply declining shark populations.
  • An international initiative that will assess the health of populations of sharks and rays in 400 different locations over a period of three years has been launched.
An up-close look at the baited remove underwater video (BRUV) camera. Copyright Global FinPrint.

Out of the 100 million sharks caught each year, scientists estimate that up to 73 million have their fins sliced off (often while still alive) to make shark fin soup — a Chinese delicacy eaten as a luxury dish at weddings and other special occasions. A growing appetite for shark fins and meat is considered the leading cause of sharply declining shark populations.

An ambitious project to conduct a global survey of sharks aims to find out how much is left of these top marine predators. Launched in July with $4 million in funding from the Paul G. Allen Family Foundation, Global FinPrint is an international initiative that will assess the health of populations of sharks and rays — aka elasmobranchs — in 400 different locations over a period of three years.

The project’s mission is “to produce the first globally standard survey of elasmobranch density and diversity across the world’s continental and insular shelves” in order to improve the understanding of the animals’ status and inform conservation efforts, according to the Global FinPrint website. “Because of a lack of consistent surveys, it is difficult to determine what pristine densities and diversities ‘should’ be to set restoration targets,” the website states.

Coral reefs teem with an abundance of beautiful underwater life. Copyright Global Finprint.

“This exciting three-year project began a few months ago and we look forward to seeing the initial results in [the] coming months. Over time, these results will help inform future funding decisions,” Raechel Waters, senior program officer for oceans at Vulcan, Inc., told Mongabay. Seattle-based Vulcan, Inc. oversees all of Microsoft-cofounder Paul Allen’s business and philanthropic activities, including Global FinPrint.

A core team of shark conservation researchers is leading the project, which will rely on a network of collaborators around the world.

The project focuses on coral reefs, where sharks play an essential role in the ecosystem, maintaining the delicate balance in the marine food web. It will target three key regions representing major areas where coral reefs occur and where existing data is sparse: the Indo-Pacific, the tropical western Atlantic, and the waters off southern and eastern Africa and the Indian Ocean islands.

In addition to estimating the number of sharks and rays in the oceans, Global FinPrint will also use the data obtained during its three-year cycle to find out how important these species are for maintaining healthy coral reefs and to understand the natural and human-driven factors that are responsible for the patterns of reef shark and ray abundance and biodiversity in the oceans.

Lead principal investigator of the Global FinPrint project, Deiman Chapman of Stony Brook University, examines a caribbean reef shark in Belize. Copyright Global Finprint.

The project’s main methodology involves deploying baited remote underwater video (BRUV) equipment to sample shark populations. BRUVs generally weigh about 100 kilograms (220 pounds), although some are lighter. They are equipped with high-definition cameras housed to withstand the pressures found at depth.

A bait bag is mounted on the BRUV frame to attract nearby sharks. When a shark comes for the bait, the BRUV unit records it. The team leaves a unit for about an hour and a half and then retrieves it to download the video, record data on the environment, and then repeat the exercise all over again. Usually four to ten units, spaced at least a kilometer apart, are deployed at a time. Based on the number and species of sharks and rays the BRUVs record in an area, the scientists estimate the size of the local populations.

“One of the important parts of the project is developing standard methods so we can compare results across the world,” Michael Heithaus, a marine biologist at Florida International University who is the co-lead principal investigator for the project, said in an email to Mongabay.

“We … use measures like maximum number of sharks of a particular species seen in a video frame at one time, rather than the total number of times any shark was seen on the video — to avoid double counting. For some species, like blacktip reef sharks, we can count the minimum number of individuals seen in a deployment by looking for individually identifiable markings on their dorsal fins.”

Mark Bond, a researcher with Global FinPrint and Stony Brook University, positions one of the baited remove underwater video (BRUV) cameras at Glover’s Reef Marine Reserve. Copyright Global Finprint.

For a project of this scale, the team is expecting problems to crop up and has designed measures to minimize them. “Whenever you work in the oceans, there will be technical glitches so we make sure that we are checking cameras and doing enough samples to reach our targets even if there is the occasional malfunction,” Heithaus said.

Although the project is still in an early stage, Heithaus is enthusiastic about the prospect of collaborating with other shark scientists.

“The number of people interested in working with the project has been really inspiring and I think that the network of collaborators that FinPrint builds will be another tangible benefit of the project,” he said. “We have now put together a sampling plan for each of the regions and have begun to pull together the many collaborators who will make such a huge effort possible.”