(CN) - Regulators have abandoned efforts to rebuild the population of critically overfished dusky sharks along the Atlantic coast, conservationists told a federal judge.
In the complaint it filed on Oct. 27 in Washington, Oceana notes that the National Marine Fisheries Service has known for years that it needs to address overfishing, voicing a goal to rebuild dusky-shark numbers over the next 100 years.
Year after year, however, the agency has continually failed to set a limit on the number of dusky sharks that could be caught of killed every year as bycatch, meaning that they are caught incidentally during the fishing of other species, Oceana says.
"By the Fisheries Service's estimate, bottom longline, handline, and troll fisheries in the U.S. Southeast region, alone, took as bycatch an average of at least 4,033 dusky sharks per year between 2006 and 2010," the complaint states.
Oceana warns that "the incomplete estimates that are available are highly uncertain; at the 95% confidence interval the average annual bycatch estimate ranges up to 10,000."
The National Marine Fisheries Service did not respond to a request for comment.
Oceana notes that the reduction of this species deprives the environment of the important ecological role of an apex predator.
"Dusky sharks are an integral part of a healthy ocean, but their numbers have been decimated by years of abuse," Oceana attorney, Andrea Treece with Earthjustice, said in a statement. "Our nation's fisheries laws require the agency to arrest this decline and to immediately rebuild this vulnerable keystone ocean predator."
Oceana says it became clear in 2011 that existing measures were not fostering adequate progress toward rebuilding the dusky-shark population.
That year, a stock assessment of dusky sharks "again concluded that the dusky shark was overfished and subject to overfishing," the complaint states.
"That assessment also concluded that the likelihood of achieving the Fisheries Service's target rebuilding date of 2108 with current levels of fishing mortality on dusky sharks was low," Oceana says. "The Fisheries Service's analysis showed that fishing mortality would need to be cut by more than half in order to achieve a 70 percent likelihood of rebuilding the dusky shark population by 2108."
Since that time, however, Oceana says the Fisheries Service has failed to make timely revisions to its management measures.
"The Fisheries Service has acknowledged for years that dusky sharks are critically depleted and in serious trouble, yet this population is still being overfished due to federal inaction," Oceana campaign director Lora Snyder said in a statement. "Three years ago, the Fisheries Service had a chance to address the situation when it proposed setting bycatch limits and closing certain dusky 'hotspots' to fishing. While this proposal was strongly supported by scientists, it was eventually withdrawn by the Fisheries Service, again leaving dusky sharks unprotected and overfished. The federal government is legally required to take action to recover this population. Any further delay is unacceptable."
Though the National Marine Fisheries Service noted signs of a mild increase in dusky shark abundance in recent years, there has nevertheless been "a continued decrease in dusky shark biomass," the complaint states.
"The same report noted that there is substantial uncertainty in abundance estimates and projections, that the population remains highly vulnerable to overfishing, and that the problem could get worse if longline fishing effort were to increase," Oceana says.
Dusky sharks have been a "species of concern" since 1997, according to the complaint, which notes that their popularity among fishermen in the late 1970s stemmed from the international shark fin trade. Fishermen have been prohibited from retaining dusky sharks since 2000.
Oceana notes that more than 80 percent of immature dusky sharks and 40 percent of adults caught as bycatch die on the line before fishermen can toss them back into the sea.
With a lifespan of at least 40 years, the dusky shark grows about 12 feet long and is "highly migratory," according to the complaint.
The species do not reach sexual maturity until they are 20 years old. Females give birth to up two dozen pups, but they reproduce only every two to three years, making them vulnerable to overfishing, Oceana says.
Dusky-shark populations appear in the Atlantic from southern Massachusetts to Florida, the Bahamas, Cuba and the northern Gulf of Mexico, ranging from shallow water of about 30 feet to water as deep as 1,300 feet, according to the complaint.
Most of the 80 to 85 percent decline in population that the species has seen in the northwestern Atlantic and Gulf of Mexico occurred between the late 1980s and 2009, Oceana says.
In addition to the Fisheries Service, Oceana's complaint takes aim at the National Oceanic and Atmospheric Administration and Commerce Department Secretary Penny Pritzker. Oceana alleges violations of the Magnuson-Stevens Fishery Conservation and Management Act, as well as the Administrative Procedure Act.
The group is represented by attorneys Treece and Stephen Roady of Earthjustice.
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