Trawls and Trash Represent One-Two Punch for Threatened Turtles [Slide Show]
Studies have identified plastic pollution and fishing practices as major threats to sea turtles for several years. This knowledge is, at last, beginning to translate into action
Credits: Courtesy of NOAA
A CHANCE TO CLEAN UP: Plastic trash covers one of the most important leatherback nesting beaches in the Dominican Republic. Much of this trash has traveled long distances on ocean currents. If not removed from the beach, it is likely to end up back in the ocean, washed off the beach by high tides, winds or storms.
Courtesy of J. Tomás and Project Nesting Sea Turtles, Dominican Republic
PLASTIC BEACH: Plastic accumulates on this sea-turtle nesting beach in an uninhabited island in the Gulf of Fonseca, bordering El Salvador. The trash makes it difficult for females to successfully nest and for hatchlings to emerge from the nest and reach the ocean. One solution to the problem of plastic debris is to work with manufacturing and design to reduce one-time-use plastic, says marine biologist Chris Pincetich, a campaigner at the Sea Turtle Restoration Project. "As consumers, we have to show we're willing to work with that and choose the products. Either [the industry] is going to do it willingly through consumer demand or by regulation. We have science showing that the continued production of plastic results in a damaged marine environment."
Courtesy of Wallace J. Nichols
OCEANS OF PLASTIC: Marc Ward of Sea Turtles Forever (SFT) removed this large snarl of fishing line and other plastics from the water on a part of the western Costa Rican coast, where STF recently documented more than 14,000 items of marine plastic debris, including more than 5,500 monofilament fishing line sections and balls. The area includes a marine-turtle foraging area, coral reef, sponge beds and sea grass beds. "I don't think one core group is focused on an international level to remove accumulated fishing gear and other debris," Ward says. Concentrating efforts on sinks, where material naturally accumulates, is most efficient, he adds. Padre Island National Seashore in Texas, the primary nesting beach for endangered Kemp's ridleys, is also a plastic sink.
Courtesy of Sea Turtles Forever
PLASTIC DIET: The trash shown was ingested by a juvenile green turtle found dead on the southern coast of Brazil. More than 260 marine species worldwide have been documented as ingesting or becoming entangled in plastic debris. Several studies have been published on plastic ingestion by sea turtles, including one in 1993 that found debris in the digestive tracts of 51 percent of loggerheads. Some necropsies have found a turtle's entire digestive tract packed with large pieces of plastic bags. One billion of these shopping bags are distributed every day, and 0.2 to 0.3 percent—millions—end up in the ocean. About half of plastic debris, including bags, are buoyant, floating on the surface and often mistaken for food by turtles, birds and other marine life. This buoyancy also allows plastics to travel with ocean currents to even remote corners of the globe. Other plastic debris sinks to the seafloor or becomes suspended at various depths in the water column.
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TURTLE ESCAPE HATCH: The National Marine Fisheries Service requires commercial operators in the Atlantic and Gulf of Mexico shrimp and summer flounder trawl fisheries to use turtle excluder devices (TEDs), which allow turtles to escape from trawl nets. The agency estimates that correct use of properly functioning TEDs could reduce sea-turtle entrapment by 97 percent. Enforcement remains an issue, though; according to the Sea Turtle Restoration Project, Louisiana state law prohibits local law enforcement from inspecting TEDs. Scientists say restrictions on trawling during certain times and in certain places are also needed, since even when TEDs allow a turtle to escape, the animal can be injured and sometimes die from those injuries—especially if it has multiple encounters.
While the majority of trawl fisheries worldwide do not require TEDs, the U.S. bans imports from countries that don't use the devices. Duke University biologist Larry Crowder notes that enforcement of the ban is problematic. He adds, "Inspectors go once a year on a pre-announced date, and guess what? The boats they look at have TEDs and the fishery gets certified for a year."
Courtesy of NOAA
DEADLY FISHING GEAR: This juvenile green turtle drowned in a beach gillnet in Valizas, Uruguay. Turtles are killed by active fishing and by lost or abandoned fishing gear, which persists in the ocean environment for long periods of time. "We need a conversation about fixing the way we fish and being smart about fishing-gear design," says biologist Wallace J. Nichols of the California Academy of Sciences. "We've accepted the idea of a high level of bycatch as normal and internalized as part of the business that you shovel over more dead animals than what you keep. That needs to change."
TURTLE BYCATCH: This juvenile green sea turtle drowned as bycatch off the coast of Uruguay. While researchers and policy makers know how to reduce bycatch, legal requirements and compliance measures are lacking, says Duke University biologist Larry Crowder. The Sea Turtle Restoration Project (STRP) has gone to court seeking better enforcement of the Marine Mammal Protection Act and adequate staff in NOAA’s Office of Protected Resources. The act requires that U.S. seafood imports be caught with means as equally protective toward marine mammals as those in the U.S., says marine biologist and STRP researcher Chris Pincetich—and those practices would also save sea turtles.
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