Protection, changing culture sees sharks flourish

In 2010 members of the Marine Conservation International/DoE team place an acoustic tag on a shark; Professor Mauvis Gore is front centre,
(Photo courtesy DoE – CLICK TO ENLARGE)

(CNS): Shark numbers are now higher in Cayman Islands’ waters than in many other Caribbean islands, research data has revealed, as a result of conservation measures and a shift in attitude towards these critically important reef predators. Although there is still some way to go to ensure that they flourish, local shark populations have benefitted from protections for all sharks in Cayman waters that were put in place four years ago in conjunction with pressing home the message that they do not steal fish from fishermen, as once believed, but actually help to keep coral reef ecosystems in balance and ensure more fish overall.

This year marks the tenth anniversary of the Department of Environment’s partnership with the UK-based non-governmental organisation, Marine Conservation International (MCI), aimed at gathering information on and protecting sharks in local waters.

DoE Director Gina Ebanks-Petrie explained that before this collaboration very little was known about the top reef predators in our ocean or why awareness was important.

“When we started the shark project ten years ago, the DoE identified this area as one where we needed to improve our scientific data collection and research,” she said. “Now, thanks to this partnership, we have much better information available to help protect these ecologically and economically important predators.”

She added, “To some extent, the attitude in Cayman towards sharks has changed over the past decade. Shark Conservation Cayman has spent a lot of time in local classrooms and talking to local fishermen about these crucial marine species. Ten years ago, the prevalent view of sharks was, if you see one, kill it. I believe that people today have a better understanding of why sharks are important to us.”

Six Caribbean reef sharks in Little Cayman in 2017
(Photo courtesy DoE – CLICK TO ENLARGE)

Stressing the need to continue the “diligent study” in order to gain “more valuable insights”, Ebanks-Petrie noted, “There is still so much we don’t know for certain about sharks in our waters.”

The creation of the Shark Conservation Cayman programme helped push for the complete protection of all elasmobranchs, which includes sharks and rays, under the Cayman Islands National Conservation Law (NCL).

The protections took effect in April 2015, making it illegal to fish for sharks and stingrays in all Cayman waters. As the NCL is relatively recent, it is difficult to gauge their overall impact, but the shark conservation partnership has documented some encouraging data.

“Our data suggest the overall abundance of sharks in Cayman Islands’ waters is currently higher than in most of the Caribbean,” said MCI Co-Director Mauvis Gore, a professor at Heriot-Watt University in Edinburgh. “However, the numbers are not quite as high as in a few places, such as the Bahamas and Belize, where sharks have been protected for longer periods.”

Tracking data shows many Caribbean shark species have a range of more than ten kilometres. “This suggests that, to be provided with adequate protection, shark species require marine protected areas on the scale of Cayman’s recent marine parks enhancement to be put in place throughout the Caribbean,” Gore said.

Large-bodied sharks, such as reef sharks, nurse sharks, hammerheads and tiger sharks, all of which are found in Cayman’s coastal waters, have significant value. The estimated non-consumptive tourism value of local shark species is between US$46 million and US$63 million. Scientists also theorise that sharks, as top marine predators, can help protect coral reefs by a “cascade” effect within the food chain.

DoE/MCI Shark Project Officer Johanna Kohler, assisted by DoE’s Mike Guderian, places an acoustic tag on a shark during a recent survey
(Photo courtesy DoE – CLICK TO ENLARGE)

“Sharks will eat a certain number of mid-level predators that feed on smaller, herbivorous reef fish. This, in turn, regulates the number of fish that eat algae from reef areas, keeping them clear for coral growth,” said DoE-MCI Shark Project Officer Johanna Kohler.

“We believe there is a correlation between a healthy shark population and healthier coral reefs,” she said, noting that sharks do not “steal” marine stocks from local fishermen. “Rather, we’ve observed they tend to bolster the numbers and health of reef fish by protecting them from mid-level predators and also by weeding out some less successful specimens, keeping the weaker ones from reproducing.”

Kohler, a PhD student from Germany, has partnered with DoE and MCI scientists for the last three years in Cayman, performing the biannual shark surveys using Baited Remote Underwater Video cameras, a non-invasive technology that allows scientists to record the sharks in their natural environment without the animals having to interact with humans.

Shark Conservation Cayman has also placed tracking devices on more than 50 local sharks over the past ten years, allowing scientists to track their movements via acoustic monitoring.

To form Shark Conservation Cayman, the DoE combined its marine and staff resources with MCI’s scientific expertise and the participation of graduate-level students, such as Kohler, to do more than either organisation would achieve on its own.

“We’d like to thank all our partners in this effort and hope to receive their continued support over the next ten years,” Gore said.

DoE and MCI and the Shark Conservation Cayman project have been the recipient of three Darwin Initiative grants from the UK Department for Environment, Food and Rural Affairs (Defra). It has also received generous donations from local brewery Caybrew and its ‘White Tip’ brand, which supports shark conservation and was developed collaboratively with DoE and MCI.

Other sponsors include the Save our Seas Foundation, Fosters Food Fair, the Southern Cross Resort and Ocean Frontiers. Project collaborators in the scientific community include Dr Edd Brooks (Cape Eleuthera Institute), Prof. John Turner (Bangor University), Prof. Callum Roberts (University of York), Dr Mahmood Shivji (Nova SE University) and Dr Guy Harvey (Guy Harvey Research Institute).

Read academic paper “Protecting Cayman Island Sharks: Monitoring, Movement and Motive” on the DoE website

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