Among the mitigation strategies that have helped reduce bycatch are: the use of circle hooks and dehooking equipment in longline fisheries, to reduce the severity of turtle injuries; the use of turtle excluder devices (TEDs) in shrimp trawl nets to allow captured sea turtles to escape; and the implementation of time-area closures to restrict fishing activities at times and places turtles are most likely to be present in the highest numbers.
Piecemeal regulation remains a problem, the study notes. Sea turtles are currently managed on a fishery-by-fishery basis, which means that bycatch limits are set for each fishery without accounting for the overall population impacts of all the takes added together. This fragmented approach leads to total allowed takes that exceed what sea turtle populations can sustain.
"Bycatch limits must be set unilaterally across all U.S. fisheries with overall impacts to populations in mind, much as it's done for marine mammals," says co-author Bryan Wallace, director of science for Conservation International's Marine Flagship Species Program and adjunct faculty member at Duke's Nicholas School of the Environment.
The researchers note that actual bycatch rates are likely higher than what the study reports because in many fisheries, particularly the shrimp trawl fishery, the number of on-board observers who document bycatch on fishing vessels is low relative to the sheer volume of fishing that is occurring.
"This paper provides a baseline to examine what is working and what can be improved in preventing sea turtle bycatch," Finkbeiner says. "It (makes) a strong case for the need for increased observer coverage a
|Contact: Tim Lucas|