Helping sea turtles off the hook
New technologies and the ecosystem approach to fisheries can help protect endangered marine species
25 March 2004, Rome -- Sea turtles have swum the seas for almost 60 million years, but decreases in their populations over the last century have many observers worried that long history could soon be coming to a close.
While the situation for sea turtle populations may vary from region to region, and more work is needed to assess their real status, of seven species of marine turtles three are listed as critically endangered and another three as endangered on the World Conservation Union (IUCN) red list of threatened species. All seven are identified by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) as threatened with extinction.
A wide range of human activities imperil these gentle giants. One source of sea turtle mortality is fishing: the turtles are accidentally captured by fishers looking to net or hook other species -- a phenomenon referred to as "by-catch" -- and usually die before they can be released.
Exact numbers for sea turtles lost to fisheries by-catch each year are hard to come by. Even harder is assessing the relative impact of fisheries on sea turtle populations, says FAO, given our limited knowledge regarding population numbers and the role of other impacts.
"As far as numbers go for fisheries-dependent mortality rates, there are more controversies than certainties. But it's generally agreed that by-catch of turtles is a problem in some regions and for some species-- and there are definitely steps we can take to reduce it," says Jorge Csirke, Chief of FAO's Marine Resources Service.
"At the same time, not all major threats to sea turtles are fisheries-related," he notes.
In many places, coastal development is destroying fragile turtle nesting areas. In others, hunger and poverty lead to harvesting of eggs -- and of the turtles themselves.
Sometimes turtles consume litter -- in particular discarded plastic bags, which look like the jellyfish they normally eat -- and are injured or die as a result.
FAO expert panel recommends use of turtle-friendly fishing gear, additional steps
To assess the extent of the problem and explore options for reducing fishing's impact on marine turtles, FAO recently convened an expert consultation on "Interactions between Sea Turtles and Fisheries in the Ecosystem Context" at its Rome headquarters.
Attended by 11 experts from seven countries, the meeting ran from 9 to 12 March and looked at issues such as sea turtle biology and conservation, the relative impacts of different sources of turtle mortality, how new fishing gear can reduce by-catch, fisheries management issues and the socio-economic context shaping human-sea turtle interactions.
The talks produced a report, still being finalized, that sets the stage for a larger, follow-up Technical Consultation to be held in Thailand later this year. The meeting in Thailand, in turn, could lead to concrete international guidelines and internationally agreed strategies for how the fishing sector can reduce its impact on marine turtle populations.
Many countries are already working to reduce by-catch of sea turtles through the use of new kinds of fishing equipment. In the Gulf of Mexico, for example, shrimp trawlers have been utilizing Turtle Excluder Devices (TEDs), which allow accidentally netted turtles to escape, since the 1980s.
This type of gear modification has now also been introduced to many other trawl fisheries around the globe, and other devices are being developed for other fishing sectors prone to turtle by-catch, such as pelagic longlining.
According to Gabriella Bianchi, an FAO fishery resources officer, the value of such innovative gear in preventing sea turtle by-catch figured prominently in last week's technical consultation.
"The use of TEDs in trawl gear and the use of circle hooks in pelagic longlining were identified as the most promising, and it was recommended that further studies be conducted to further develop longline and trawl modifications for adoption by various countries and regions," she says.
The need for more research into other modifications to fishing gear and methods to prevent by-catch -- such as altering the depth at which hooklines are set or using different types and sizes of hooks -- was also discussed by the panel.
In addition, the group of experts called on FAO to help fill data gaps regarding sea turtle-fisheries interactions and asked the agency to produce a set of turtle handling and release guidelines in order to educate fishers in the proper release of trapped turtles found alive during gear retrieval.
Casting a wider net
According to Ichiro Nomura, FAO Assistant Director-General and head of the agency's Fisheries Department, inclusion of conservation considerations in fisheries management is not a new development.
"Although it does not specifically address sea turtles, FAO's Code of Conduct for Responsible Fisheries, adopted in 1995, calls for a sustainable use of aquatic ecosystems and requires that fishing be conducted 'with due regard' for the environment," he says. "It also addresses specifically biodiversity issues and conservation of endangered species and in so doing, calls for the catch of non-target species, both fish and non-fish species, to be minimized."
Accordingly, recommends FAO, integration of conservation considerations in fisheries management and the adoption of gear-based and other approaches to reducing fishing's impacts on turtles should be implemented within a broader strategy: the ecosystem approach to fisheries.
The idea is to incorporate ecosystem considerations into fisheries management plans so that the wellbeing of not only target species but of the overall ecosystem -- including human fishing communities as well as animal and plant populations -- is promoted.
The approach aims not only to protect biodiversity and the environment, however: it also offers a way to improve fisheries production.
"If we preserve and improve overall ecosystem health and productivity now -- that is, look to the balanced wellbeing of all marine animals and plants in a given area -- we will be able to maintain, and even increase, fisheries production in that area over the long run," explains Mr Csirke.
"Over 840 million people on the planet don't have enough to eat, and fisheries play a vital role in bolstering food security and providing employment," he adds. "Healthy fisheries and healthy ecosystems are not mutually exclusive. The ecosystem approach to fisheries points the way."
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