Catching Sharks On Camera: study of shark populations inside and outside protected areas

A press release from the Institute for Ocean Conservation Science has been making the rounds lately, explaining the Institute's research on reef shark populations within and outside of protected areas. Using techniques borrowed from researchers who study jungle cat populations, the ocean researchers used "chum cams" to attract and record sharks within two protected areas and two areas open for fishing. Their results add to the growing need for more marine protected areas.

'Chum cam' underwater video survey shows that reef sharks thrive in marine reserves

Study led by scientists from the Institute for Ocean Conservation Science at Stony Brook University uses video cameras to count reef sharks, showing that marine reserves benfit these top predators on the world's second largest barrier reef

STONY BROOK, NY -- A team of scientists, led by the Institute for Ocean Conservation Science at Stony Brook University, used video cameras to count Caribbean reef sharks (Carcharhinus perezi) inside and outside marine reserves on the Mesoamerican Barrier Reef in the Caribbean Sea. Using survey data collected from 200 baited remote underwater video (BRUV) cameras, nicknamed "chum cams," the scientists compared the relative abundance of these reef sharks in two marine reserves with those in two areas where fishing is allowed, and demonstrated that the sharks were more abundant in the reserves.

The research findings appear in the paper, "Reef sharks exhibit site-fidelity and higher relative abundance in marine reserves on the Mesoamerican Barrier Reef," published online today in the journal PLoS ONE. The purpose of the study, conducted from 2005 through 2010, was to test the hypothesis that carcharhinid shark species, which include requiem and whaler sharks, are more abundant inside no-take marine reserves where fishing for sharks and their prey is prohibited. The authors tested the hypothesis by using BRUV surveys to determine the reef sharks' numbers, and combined these results with acoustic monitoring to measure their site fidelity (remaining within the same local area) in Glover's Reef Marine Reserve, Caye Caulker Marine Reserve, and two reefs where fishing is allowed, all located in Belize.

"Although we know that relatively sedentary reef fish and lobsters benefit from marine reserves, this study now presents visual proof that large, active sharks are also dramatically more abundant inside these protected areas, too," said Mark Bond, lead author and doctoral student at Stony Brook University. "Nearly four times as many chum cam deployments in the marine reserves recorded reef sharks than on similar fished reefs. These areas provide the sharks and other coral reef species a respite from fishing, which means decreased fishing mortality for the sharks and more prey for them to eat."

The video cameras were enclosed in protective housing, and placed on the sea floor with small bait-filled cages positioned in front of them. Sharks, attracted by the smell of the bait, swam to the cameras, which allowed the research team to record, count, and compare shark populations in the marine reserves to those in the areas where fishing is permitted, at no stress to the sharks. In addition to the BRUV surveys, the scientists fitted 34 reef sharks with acoustic transmitters, and tracked their movements, using moored underwater listening stations. They found that the sharks, both juveniles and adults, live year-round within the reserves.

"Scientists who study tigers or jaguars in the wild use camera traps to count them," said Dr. Demian Chapman, assistant professor in the School of Marine & Atmospheric Science at Stony Brook, leader of the research team and assistant director of science of the Institute for Ocean Conservation Science. "It is just as difficult to count sharks in the ocean, so we took a page from the big cat researchers' playbook and deployed baited video cameras to count the sharks. It's only fitting since these large apex predators are the 'big cats' of the sea, and like their feline counterparts, their continued existence on Earth is threatened."

Due to intense fishing, Caribbean reef sharks are listed as "Near Threatened" by the International Union for the Conservation of Nature (IUCN) but it is possible they will be upgraded to "Vulnerable" by IUCN as more data are collected. They live in the western Atlantic Ocean, ranging from Bermuda to southern Brazil, and are the only Atlantic requiem shark species that undergoes its entire life cycles within coral reef ecosystems.

"Caribbean reef sharks and other shark species around the world are threatened by overfishing," said Dr. Ellen K. Pikitch, a professor in the Stony Brook University School of Marine and Atmospheric Sciences, who co-authored the paper and is executive director of the Institute for Ocean Conservation Science. "Our study demonstrates that marine reserves can help protect shark species that live on coral reefs. Moreover, the use of underwater video monitoring provides us with an excellent tool to determine if populations are recovering and thriving inside these reserves."

"As the saying goes, a picture is worth a thousand words," said Bond. "As Caribbean nations and other countries consider developing marine reserves, chum cams can virtually transport policy makers and the public beneath the waves and show them the benefits of these protected areas."

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This research was funded by the Roe Foundation, The Pew Charitable Trusts, and other sponsors of the Institute for Ocean Conservation Science.

Source: Eurekalert.org
Source: Institute for Ocean Conservation Science

Cayman Island Shark Study: results show less than expected numbers

Making a strong case for shark conservation requires more than an appeal to the emotions. Railing against the practice of shark finning or positioning sharks as cuddly creatures who mean no harm can generate sympathy among portions of the general populace, but it's hard facts that are required to convince politicians and policymakers that steps need to be taken to protect these ocean predators.

For the past three years, the Cayman Islands have been host to a group of marine researchers who have been conducting a population study of sharks and rays in and around the islands. A joint effort between the Save Our Seas Foundation and Marine Conservation International, the project was coordinated by the Cayman Island's department of the environment and funded in part by the UK's Overseas Territory Environment Programme, the Guy Harvey Ocean Foundation, and others. A presentation was recently held to summarize the findings and while anyone familiar with the current state of shark populations might expect the reported numbers to be low, what the researchers found to be most disconcerting was there appears to be far fewer species in local waters than expected.

At the presentation, several of the researchers involved with the project, including Dr. Mauvis Gore and Professor Rupert Ormond, made a strong case for shark conservation with the usual arguments regarding the overfishing of sharks, the positive impact that sharks have in maintaining balance within local marine ecosystems, and the multimillion dollar difference in economic value between shark consumption and shark tourism value - often by a factor of x50 or more in favor of tourism. These are many of the same justifications used to support shark protections or sanctuaries in other countries.

However, what was of particular concern to the scientists was what their research found that was unique to the Cayman Islands. Several species that historically were common in Cayman waters were found to be in much smaller numbers, if found at all. The Cayman News Service reported that, as part of the study, the researchers conducted tagging of several sharks species to track their movements and, as has been documented by others, sharks like tiger sharks, oceanic whitetips, and others were found to cover considerable distances. This presents the need for establishing cooperative policies between other nearby countries as the sharks will not be paying much attention to the boundaries of local shark protected areas or sanctuaries.

"Although the tracking has helped the scientists learn more about the sharks their failure to even find key species in the area to tag such as hammerheads has limited the research but so far the scientists are able to conclude that Cayman has only a modest number of sharks and a lower than expected variety of species. Dr Gore said the scarcity of hammerheads was a concern given that in the 1970s it was possible to sea schools of this type of shark in local waters. 'People think I’m mad when I say this,' she said, given the current scarcity of the species here."

With the environment minister, Mark Scotland, calling the study's results as "eye opening," perhaps we will see action in the near future to establish protections in the Cayman's local waters combined with collaborative efforts between the Cayman Islands and neighboring countries like Mexico, Honduras, the Bahamas and others. For shark conservationists, this would be welcomed news.

Source: Cayman News Service

Sharks in the Arabian Gulf: new research to determine population before it's too late

Declining shark populations have been reported in many parts of the world - some reductions reaching as much as 80 to 90 percent compared to just a few decades ago. But there are still some important bodies of water where the status of the shark populations is unclear. One of those bodies is the Arabian Gulf (or Persian Gulf, depending on who you talk to).

But that is about to change.

Marine biologist Rima Jabado, from the United Arab Emirates (UAE) University, has begun a study to determine the health and extant of shark populations in the Gulf. As part of her doctoral thesis, she has been interviewing Arab fishermen (over 125 to date) and their anecdotal information combined with in-the-field study will hopefully paint an accurate picture of what shark species are living in the Gulf and what their true numbers are.

Jabado was pleased to find that the fishermen were sympathetic to the need for shark conservation to maintain a healthy marine ecosystem, thereby helping to provide sustainable levels of commercial fisheries. But, as noted in the Gulf News, she also heard their frustration in how to deal with sharks when caught.

"The majority of the fishermen would want to protect sharks and believe in the protection of fish for a sustainable fishery," said Rima. "But if sharks are caught in a fisherman's net, should they be thrown back? Perhaps they should be brought in? [This subject] causes them to debate. Some complain that sharks just make holes in their nets."

In many publications, including this blog, the impact of declining shark populations on marine ecosystems has often been presented as a looming threat. But scientists and commercial fisherman are beginning to see real, tangible evidence.

For its predominantly international audience, the Gulf News cited several examples ranging from Australian reports of octopus - no longer being preyed upon by sharks - exploding in number and devouring the lobster population; to increased numbers of cownose rays along the U.S. Atlantic coast decimating vast beds of bay scallops (sharks, particularly hammerheads, feed on cownose rays).

Hopefully, Jabado's research will provide UAE government officials with hard evidence from which responsible shark conservation policies and fishing regulations can be derived. While the Arab fisherman expressed an interest in shark conservation to insure the future of their fisheries, the catch numbers have not been so flattering. According to the Food and Agriculture Organization, UAE's catch alone of sharks averaged between 1,300 and 1,950 tons annually from 1985 to 2000. While that number remained fairly stable through that period, rather than increasing, it certainly is sufficient to cause harm to shark populations in a relatively closed body of water like the Arabian Gulf.

"The state of sharks in the Arabian Gulf is a blank," said Jabado. "Attention should be given to sharks — they're the apex predator and their demise could lead to the collapse of the marine ecosystem."

Let us hope that the Arab nations that border the Gulf will prove to be more long-term in their thinking when it comes to establishing policy that will preserve both sharks and their commercial fishing interests.

Read entire article in the Gulf News.