A turtle excluder device (TED) is a specialized device that allows a captured sea turtle to escape when caught in a fisherman's net.
In particular, sea turtles can be caught when bottom trawling is used by the commercial shrimp fishing industry. In order to catch shrimp, a fine meshed trawl net is needed. This results in large amounts of other marine organisms being also caught as bycatch. When a turtle gets caught or entangled in a trawl net, it becomes trapped and is unable to return to the surface. Since sea turtles are air-breathing animals with lungs, they cannot survive long underwater without surfacing and will eventually drown.
The first TED, was based on a device called the jellyball shooter, that is used to removed cannonball jellyfish from shrimp trawl. [1] [2] TEDs were later developed in the 1970s by Wil Seidel, who worked for NOAA. Some resistance to the use of TEDs has arisen from the belief that the use of the devices actually causes fishermen to lose shrimp and other targeted species. [3]
In 1987, the United States required all shrimp trawlers to equip their nets with turtle excluder devices. [4] Two years later the shrimp-turtle law was implemented. This required all countries that export shrimp to the US to certify that the shrimp they shipped were harvested by boats equipped with TEDs. Countries that cannot guarantee the use of the escape devices were banned from exporting shrimp to the US. [5]
In 1996, the government of India proposed legislation for the requirement of modified "indigenous" TEDs, which they called TSDs (turtle saving devices), to be used by local fishermen. This was a response to the declining olive ridley population that were nesting in beaches such as in Odisha. The modified TSDs were similar to standard TEDs except for having fewer bars. This resulted in the increase of the distance between each pair of bars to ensure that bigger specimens of shrimp and fish were able to pass through the TSD and into the net. [6]
The use of the devices ideally allow all bycatch larger than ten centimeters (10 cm) to escape the nets unharmed. This selectivity is achieved by metal grids integrated into the trawl net structure. The grids act as a barrier for keeping large creatures such as turtles from passing through the bars into the back of the net. [7]
A small opening in the net is then available either above or below the grid so that the creatures that are stopped by the TEDs are allowed to escape the net, relatively unharmed. Targeted species such as shrimp however, are pushed to the back of the net. The target design effectiveness of TEDs is 97%, [8] but the field effectiveness is often far lower. Seagrasses and other debris reduce fishing effectiveness of TEDs and in some situations may block sea turtles from exiting the net. [9] In addition, it is easy to tamper with TEDs so as to increase the fishing efficiency of the net, while eliminating the turtle-excluding properties of the TED. [10]
While turtle excluder devices have been somewhat successful in lessening sea turtle casualties as by-catch, they still have a few failings and drawbacks.
It has been acknowledged that the larger sea turtles, primarily large loggerheads and leatherbacks, are too large to fit through the escape hatches installed in most TEDs. These turtles remain trapped within the net and perish. U.S. legislation introduced in 2003 attempted to address this issue by increasing the size of the escape chutes in the devices. [5]
It is difficult to enforce TED compliance as TEDs can reduce the efficiency of the net system, resulting in a loss of some of the catch. On a per boat basis, turtles are rarely caught; in one study, only one turtle was caught per 322.5 hours in the Gulf of Mexico. [11] This creates an incentive for the trawler to cheat. The catch loss can be eliminated by simply tying the turtle escape opening shut with a tie. The tie is removed when the vessel returns to port, thus avoiding detection by enforcement officers, but placing turtles at risk while trawling. It has been theorized that the spike in dead turtles seen in the Gulf of Mexico in June and July 2010 was due to shrimp boats that were taking advantage of lax marine enforcement due to the gulf oil spill. [12]
Occasionally TED use becomes impractical due to debris in the water. When a TED is clogged with debris, it can no longer catch fish effectively or exclude turtles. For example, in September 2008 following Hurricanes Gustav and Ike, the National Marine Fisheries Service (NMFS) allowed temporary use of "Tow Times" in lieu of TEDs. Vessels were required to limit their tows to 55 minutes from the time the trawl doors entered the water until they were retrieved from the water. In June 2010 the limit was further reduced to 30 minutes. [13] However, vessels were not equipped with tow time data loggers, so there was no practical method to enforce these time limits. [14]
The TTED (trash and turtle excluder device) is a refinement of the TED, which, as well as turtles, can additionally free other forms of bycatch; "trash" refers to these other species. [15] The TTED reduces sorting time and risks of injury due to sharks and rays being caught, improves the quality of shrimps, which are less likely to be crushed in the bottom of the trawl, and may also lead to a reduction in the amount of fuel consumed by the boats. [16]
The TTED is the culmination of years of research. With funding provided by the European Union and the DIREN (Regional Environmental Authorities), WWF commissioned a study from IFREMER (French Research Institute for Exploitation of the Sea) to determine which selective gear was the most adapted to fishing conditions in French Guiana. These initial trials, conducted under experimental conditions, were carried out on board a shrimp trawler. Following this work, shrimp industry's members expressed the need to continue these experiments and to become more involved in the project. In response, WWF and the CRPMEMG (French Guiana Regional Fishery and Ocean Farming Committee) began working in close collaboration in order to test and develop the best gear for the French Guiana fleet. [16]
With technical support from NOAA and IFREMER, the CRPMEMG carried out numerous at sea trials in close collaboration with French Guiana fleets. [15] Specific parameters were tested, such as the shape and spacing between the bars of the selective grid. These trials allowed the fleets and the crews on board the shrimp trawlers to understand the advantages of more selective fishing gear and the benefits of using it in French Guiana. Based on the results and the captains' recommendations, the CRPMEMG decided to make the use of this TTED system mandatory by January 2010, when the annual fishing licences are issued. Many Captains were already using the TTED device on their shrimp trawlers well before January 2010. [16]
The TTED was developed by the CRPMEMG and fishermen with the assistance of NOAA, IFREMER, the French Ministry of Agriculture and Fisheries, French Guiana, the European Fund for Fisheries (FEP) and the WWF. [16]
Trawling is an industrial method of fishing that involves pulling a fishing net, which is heavily weighted to keep it on the seafloor, through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different species of fishes or sometimes targeted species. Trawls are often called towed gear or dragged gear.
Longline fishing, or longlining, is a commercial fishing angling technique that uses a long main line with baited hooks attached at intervals via short branch lines called snoods or gangions. A snood is attached to the main line using a clip or swivel, with the hook at the other end. Longlines are classified mainly by where they are placed in the water column. This can be at the surface or at the bottom. Lines can also be set by means of an anchor, or left to drift. Hundreds or even thousands of baited hooks can hang from a single line. This can lead to many deaths of different marine species. Longliners – fishing vessels rigged for longlining – commonly target swordfish, tuna, halibut, sablefish and many other species.
Bycatch, in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juveniles of the target species. The term "bycatch" is also sometimes used for untargeted catch in other forms of animal harvesting or collecting. Non-marine species that are caught but regarded as generally "undesirable" are referred to as rough fish or coarse fish.
Bottom trawling is trawling along the seafloor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing a net at the very bottom of the ocean and demersal trawling is towing a net just above the benthic zone. Bottom trawling can be contrasted with midwater trawling, where a net is towed higher in the water column. Midwater trawling catches pelagic fish such as anchovies and mackerel, whereas bottom trawling targets both bottom-living fish (groundfish) and semi-pelagic species such as cod, squid, shrimp, and rockfish.
Cetacean bycatch is the accidental capture of non-target cetacean species such as dolphins, porpoises, and whales by fisheries. Bycatch can be caused by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets.
The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the stewardship of U.S. national marine resources. It conserves and manages fisheries to promote sustainability and prevent lost economic potential associated with overfishing, declining species, and degraded habitats.
The shrimp fishery is a major global industry, with more than 3.4 million tons caught per year, chiefly in Asia. Rates of bycatch are unusually high for shrimp fishing, with the capture of sea turtles being especially contentious.
Kemp's ridley sea turtle, also called commonly the Atlantic ridley sea turtle, Kemp's ridley turtle, and Kemp's ridley, is a species of turtle in the family Cheloniidae. L. kempii is the rarest species of sea turtle and is the world's most endangered species of sea turtle. It is one of two living species in the genus Lepidochelys. The species L. kempii primarily occupies habitat around the Gulf of Mexico, though its migrations into the Atlantic Ocean are being affected by rising temperatures. Kemp's ridley sea turtle is listed as endangered under the Endangered Species Act (ESA), and conservation efforts are attempting to rebuild population numbers. Human activity, including but not limited to habitat destruction, climate change, and oil spills, threaten populations.
Unsustainable fishing methods refers to the use of various fishing methods used to capture or harvest fish at a rate which is unsustainable for fish populations. These methods facilitate destructive fishing practices that damage ecosystems within the ocean, and result in overfishing.
The barndoor skate is a species of marine cartilaginous fish in the skate family Rajidae of the order Rajiformes. It is native to the northwestern Atlantic Ocean, and is found from the Grand Banks of Newfoundland and the southern side of the Gulf of St. Lawrence south to North Carolina. The fish is one of the largest skates found in the North Atlantic Ocean, reaching lengths up to 1.5 m (5 ft). It is carnivorous, feeding on invertebrates and other fish found near the sea floor.
The environmental impact of fishing includes issues such as the availability of fish, overfishing, fisheries, and fisheries management; as well as the impact of industrial fishing on other elements of the environment, such as bycatch. These issues are part of marine conservation, and are addressed in fisheries science programs. According to a 2019 FAO report, global production of fish, crustaceans, molluscs and other aquatic animals has continued to grow and reached 172.6 million tonnes in 2017, with an increase of 4.1 percent compared with 2016. There is a growing gap between the supply of fish and demand, due in part to world population growth.
The giant guitarfish, also known as the whitespotted wedgefish, is a large species of guitarfish in the family Rhinidae. It is restricted to the Red Sea, Persian Gulf, and western Indian Ocean, but was formerly considered more widespread due to confusion with its relatives.
In 1994, the WTO intervened to address member concerns regarding the import of shrimp and its impact on turtles. This became known as the Shrimp and Turtle case. The ruling was adopted on November 6, 1998. However, Malaysia persisted in their complaint and initiated DSU Article 21.5 proceedings against the U.S. in 2001, but the U.S. prevailed in those hearings.
This is a glossary of terms used in fisheries, fisheries management and fisheries science.
As with other countries, the 200 nautical miles (370 km) exclusive economic zone (EEZ) off the coast of the United States gives its fishing industry special fishing rights. It covers 11.4 million square kilometres, which is the second largest zone in the world, exceeding the land area of the United States.
The Gulf flounder is a species of saltwater flounder.
In the fishery business, a bycatch reduction device is a tool designed to minimize unintended capture of marine animals, to reduce the adverse effects of fishing on the ecosystem.
The Hawaii longline fishery is managed under Western Pacific Regional Fishery Management Council’s (WPRFMC's) Pelagics Fisheries Ecosystem Plan. Through this plan, the WPRFMC has introduced logbooks, observers, vessel monitoring systems, fishing gear modifications and spatial management for the Hawaii longline fishery. Until relatively recently, the main driver for management of the Hawaii longline fishery has been bycatch and not fishery resources.
Worldwide, hundreds of thousands of sea turtles a year are accidentally caught in shrimp trawl nets, on longline hooks and in fishing gill-nets. Sea turtles need to reach the surface to breathe, and therefore many drown once caught. Loggerhead and hawksbill turtles are particularly vulnerable. Nearly all species of sea turtle are classified as Endangered. They are killed for their eggs, meat, skin and shells. They also face habitat destruction. Climate change has an impact on turtle nesting sites. As fishing activity expands, this threat is more of a problem.
NOAAS Oregon, previously NOAAS Oregon, was an American fisheries research vessel in commission in the National Oceanic and Atmospheric Administration (NOAA) fleet from 1970 to 1980. Prior to her NOAA career, she operated under the United States Fish and Wildlife Service from 1949 to 1970 as US FWS Oregon.