Calling all underwater photographers: Snapshots of sharks and large snappers and groupers are needed for a research project about local marine predators.

The Department of Environment and Marine Conservation International would like divers and snorkelers in the Cayman Islands to contribute to the new project by taking photos. They have created a hashtag, #SpotThatCayfish, to upload the photographs on Facebook or Twitter.

The “citizen science” program is aimed at supporting the management of sustainable marine populations and healthy reefs in the Cayman Islands.

“The Citizen Science Program is all about getting the public involved,” said Johanna Kohler of Marine Conservation International, a U.K. partnership of marine scientists.

“Cayman’s DoE and Marine Conservation International monitor grouper, snapper and shark populations to gain more information about these groups to better understand them,” she said. “This will help in improving fisheries management to achieve sustainable local grouper and snapper populations. Also, it aids in a better protection for sharks which are a key predator for coral reef health in Cayman.”

This Nassau grouper is one of the first contributions to the #SpotThatCayfish project. – Photo: Helen Walter
This Nassau grouper is one of the first contributions to the #SpotThatCayfish project. – Photo: Helen Walter

MCI asks those who post photographs to include information about the date, time and dive site where the species was spotted; information about the species, sex and size of the fish, if possible; and to note whether a shark has a fin tag. This helps researchers learn about the habitat and home range of an individual fish.

Collecting data on individual sharks and fish gives researchers a better idea about what sort of protections – such as marine parks – they need, said Department of Environment research officer John Bothwell.

“We know we need decently large sized protected areas,” Mr. Bothwell said. “We don’t want to make them too big because we do want the fish to spill over into the fishing zones, so it’s about finding the right size. We think we have well-sized proposed areas; this just adds more information so we can check what we’re doing.”

Marine predators are of particular interest to researchers because they have a key role in sustaining reef health by maintaining the balance of the food chain and controlling smaller predators. When there are too many small predatory fish in a reef, there are fewer herbivores, such as parrotfish, which prevent algae overgrowth on the reefs.

Also, shark and predatory fish populations grow very slowly, mature late and have long pregnancies, which makes them highly vulnerable to fishing. Mr. Bothwell said they are looking for pictures of sharks, mutton and gray snappers, lagoon snappers and any big grouper, but particularly, Nassau and black groupers.

“We know we have great photographers around here,” Mr. Bothwell said. “They can get us really good quality pictures of our fish and so, from that, our partners at MCI can sit down and go through them and start identifying specific fish.”

Researchers compare the photographs and can distinguish fish based on their patterns and features.

“The pattern – stripes, dots – on the head and body of groupers and snappers is different between individuals,” Ms. Kohler said. “In the case of sharks, we also use their sex and dorsal fin shape and outline in addition to distinctive markings on their body to ID individuals.”

The call for photographs is part of the DoE and MCI’s “Top Marine Predators Project,” funded largely by a U.K. Darwin Plus award, and also supported by a portion of profits from Cayman Island Brewery’s White Tip lager.

As the data is collected, MCI researches will provide updates on social media.

Individuals who would like to get involved in the project or follow its progress may join the Facebook group ‘Sharks & Cetaceans: The Cayman Islands’ and follow the progress of the project by typing #SpotThatCayfish in the search bar on Facebook and Twitter to view all the photos that people have posted.