Loggerheads are caught in U.S. trawls in greater numbers than other turtle species.David Godfrey/CCC.
Each year hundreds, and possibly thousands, of immature and adult sea turtles are inadvertently captured, injured or killed by U.S. trawlers in the Atlantic and Gulf of Mexico. When turtles are caught in trawl nets, they are unable to surface to breathe and may die if they remain underwater for more than 30 minutes. Loggerheads are caught in trawls in greater numbers than other species, but Kemp’s ridleys, greens, leatherbacks and hawksbills are also captured. Fortunately, trawl nets can be modified to include a simple turtle excluder device, or TED, to release sea turtles and other entrapped animals.
TEDs were developed more than 27 years ago after biologists identified shrimp trawls as a major threat to sea turtles in the late 1970s. Trawls are wide-mouthed nets which taper from a large opening to a bag for the catch. First developed by Georgia shrimpers to exclude cannonball jellyfish and marine debris, TEDs are inexpensive net inserts with bars surrounded by a frame and placed near the back of the net. Designed to allow target fish or shrimp to pass through the bars into the catch bag, TEDs guide turtles out of the net through a top or bottom exit.
Unfortunately, U.S. shrimpers fought having to use this gear for many years, despite the fact that scientists identified shrimp trawls as the greatest source of U.S. sea turtle mortality, greater than all other sources combined. The refusal by American shrimpers to use TEDs evolved into an enormous natural resource controversy that was not resolved until 1992. At that time, laws were implemented requiring U.S. shrimpers to use TEDs throughout the year in all state and federal waters from Texas to the Virginia-North Carolina border. During the years of delay, tens of thousands of sea turtles perished, and conservationists feared the Kemp’s ridley would go extinct.
During the last 16 years, TED regulations have been modified and improved, including requirements for larger exit openings to ensure the biggest turtles could escape. Despite their success in the shrimp fleet, TEDs are not yet required on thousands of other U.S. trawlers in the Atlantic and Gulf of Mexico that fish for numerous other species, such as scup, black sea bass, tilefish, Atlantic bluefish and herring, mackerel, squid, butterfish, Mid-Atlantic sea scallops, whelks, blue crabs, horseshoe crabs, cannonball jellyfish, monkfish, skates, spiny dogfish, Atlantic croaker, and weakfish. These commercial trawlers land millions of pounds of catch each year, and many operate in areas where sea turtle interactions are likely, but the National Marine Fisheries Service (NMFS) does not require them to use TEDs.
NMFS has delayed enacting widespread TED regulations for years. In 2001 NMFS announced it was developing a “Strategy for Sea Turtle Conservation in Relation to Atlantic and Gulf of Mexico Fisheries,” with the goal of addressing problems by gear type. Although trawls are the Strategy’s first priority, NMFS did not publish An Advance Notice of Proposed Rule-making for these fisheries until February 2007 and then for only Mid-Atlantic trawls. CCC’s advocacy for a comprehensive rule requiring TEDs in all U.S. trawls includes meetings with the head of NMFS, important NMFS regional staff, Congressional offices and committee staff, and state officials as well as letters and official comments.
Accurate estimates of capture and mortality in trawls are difficult to make because observer coverage for many fisheries is low. However, one thing is clear: as coverage of all fisheries increases, estimates of turtle capture increase. Since 2001, the conservation community and government biologists have urged NMFS to require TEDs in all trawls interacting with turtles from Maine to Texas. Some modifications to existing TED designs may be necessary, but net specialists opine TEDs used by the shrimp fleet will be effective for many trawl fisheries. NMFS has conducted successful TED research with fishermen using flynets and trawls for whelk and Mid-Atlantic sea scallops, and tests are underway in other fisheries.
With the exception of the shrimp fishery, which is federally regulated, most states do not require trawl fishermen to use TEDs. Georgia is the exception with its requirements for TEDs in all trawl fisheries. South Carolina requires TEDs in the whelk fishery when sea turtles are present, and Florida mandates TEDs in skimmer nets. Maryland, Virginia and Florida have designated areas permanently closed to trawling. At the other end of the spectrum, Louisiana has refused to enforce federal TED regulations for shrimp trawls in state waters since federal regulations went into effect in 1992.
Turtle Excluder Devices are designed to be inserted into trawl fishing nets and allow entrapped sea turtles to easily escape from a trawl net while it is being pulled behind a fishing vessel. This photo shows a TED frame with the escape flap open. NOAA File Image.
TEDs allow entrapped sea turtles to easily escape trawls, but in areas with intense fishing, a turtle caught multiple times within a few hours can die as a result of physiological changes brought about by forced submergence and stress. For example, each year the waters off Texas are closed out to 200 miles for a two month period to allow shrimp to grow to an optimal market size. When the area opens to fishing, shrimp boats arrive from throughout the Gulf of Mexico. Time and area restrictions are the most effective solution for preventing sea turtle capture during this pulse of intense fishing effort. Shrimpers also drown turtles in small trynets (less than 10 feet across) not equipped with TEDs. Trynets sample catch several times an hour, but many fishermen leave them in the water for several hours to catch shrimp rather than sample.
TEDs also have been required in the summer flounder trawl fishery for many years, but they are not as effective as they could be. When NMFS required shrimpers to increase TED opening sizes in 2003, it made a commitment to change exit sizes in the summer flounder fishery, but has not yet done so.
One design which has become increasingly popular is the skimmer trawl. Unlike most trawls nets which are towed, skimmers are pushed through the water to capture fish or shrimp. These nets catch fewer nontarget animals (bycatch) than other trawls and are often the gear of choice for fishermen replacing gillnets. Skimmers are used in substantial numbers in the inshore waters of Louisiana, North Carolina, Mississippi, and Alabama. In 2004 more than 3,400 skimmers were registered in Louisiana alone. Skimmers fishing for shrimp empty their nets about every 30 minutes and thus may not be problematic for turtles. Research indicates, however, that skimmers catching finfish remain in the water well over an hour and thus need to use TEDs.
Shrimp trawling is also a major problem for sea turtles in other parts of the world, with an estimated mortality of 150,000 animals per year. In 1989, in an effort to level the playing field for U.S. shrimpers and promote sea turtle conservation, the Congress passed Section 609 of Public Law 101-162 requiring all wild-caught imported shrimp to be caught with net equipped TEDs (nearly 80% of U.S. shrimp is imported but much is farm-raised). Over several years these restrictions were challenged under World Trade Organization (WTO) rules, but ultimately the right of the United States to protect the environment was upheld. The newly released movie “Battle in Seattle” immortalizes the 1999 hotly contested WTO shrimp-turtle issue in film.
Several officials have told us NMFS now plans to phase in comprehensive TED regulations starting in mid-2009. We will continue to follow this issue closely and work to resolve existing problems in the shrimp and summer flounder fisheries.