Global Hotspot for Sea Turtle Bycatch Along Baja California, Mexico
|Dead loggerhead sea turtles recovered from gillnets in Baja, Mexico during the Summer of 2012. Scientists estimate a 600% increase in loggerhead bycatch occurred in Baja last Summer.|
Mexico’s nearshore fisheries kill sea turtles at a level only seen by large commercial fleets
San Francisco – A comprehensive global evaluation of fisheries bycatch impacts on endangered sea turtles and other large marine species, published this month in the journal Ecosphere, revealed that sea turtle populations in the East Pacific face much higher bycatch and mortality rates than previously estimated. Specifically, the study found that bycatch rates in small-scale fisheries in nearshore areas rival those of large-scale commerical fisheries in the open ocean. Currently, six out of the seven species of sea turtles are endangered globally, and without effective measures to reduce bycatch, many sea turtle populations around the world could face local extinction.
The highest bycatch rates in the world have been documented in small-scale fishing gear off Baja California, Mexico. Despite numbering only 100 boats, this small fishing fleet accidentally catches and kills as many endangered loggerhead turtles each year as all other fisheries in the North Pacific combined. Just last year, more than 2,000 turtles of this endangered population were killed—a 600-percent increase over previous mortality estimates. That situation has prompted the Turtle Island Restoration Network, an ocean conservation advocacy group in California, to pressure the government of Mexico to enact new regulations to protect endangered loggerheads there.
Click here for the Turtle Island Restoration Network action alert to halt the killing of loggerheads in Baja gillnets.
Click here to view the full scientific study in Ecosphere.
“Californians hoping to see a loggerhead sea turtle offshore have little chance if we can’t stop gillnet fisherman in Baja from killing thousands of them every year,” said Dr. Chris Pincetich of the Turtle Island Restoration Network. “We’re hopeful that as neighbors sharing the same marine ecosystem, the government in Baja Mexico will respond to the thousands of Californians that have already sent messages in support of ending the bycatch through our SeaTurtles.org website.”
“Fisheries and environment managers in Mexico can reduce loggerhead bycatch by protecting turtles in their important feeding and breeding areas, managing the amount and types of gear being used and working with small-scale fishermen to implement techniques that reduce bycatch,” said Dr. Bryan Wallace of Oceanic Society and Duke University, a co-author of the study. “The loggerhead bycatch situation is being closely watched around the world, so if it is handled well, it could be a great model for other places to follow.”
“We lose hundreds or thousands of turtles each year in populations that are already at risk,” said Dr. Wallace. “Many sea turtle populations around the world could face local extinction if we don’t reduce bycatch.”
The findings are the result of a comprehensive assessment of fisheries bycatch – the accidental capture and injury of marine animals in fishing gear that are not the target catch species – from multiple fishing gears to-date for any large marine species. Researchers at Conservation International, Oceanic Society, San Diego State University, Duke University and Stanford University analyzed data from more than 1800 bycatch records over the last two decades to determine the regions and types of fishing gear with the highest impacts on sea turtles.
“This study should serve as an initial roadmap to prioritize investment of limited resources to sustainably manage fisheries to minimize bycatch,” Wallace continued. “Our analyses demonstrate where and how sea turtles are being accidentally killed and inform decisions on what steps we can take to reverse the decline of turtle populations.”
Sea turtles play important roles in maintaining healthy marine ecosystems. They feed on sea grasses, sponges and jellyfish, which can help to maintain habitats that serve as nurseries for other species and support healthy fish populations.
The analysis also exposed significant gaps in available bycatch data in the Gulf of Mexico, around Africa, in the North Indian Ocean and in Southeast Asia, which prevented researchers from evaluating bycatch rates in these regions. Turtle populations in these international regions are already under high threat from human exploitation of their eggs, meat and shell material, and fishing activity in areas that turtles inhabit is high.
A study published last year in Biological Conservation, which Wallace co-authored, illustrated that several tools are available to managers to reduce mortality of sea turtles due to bycatch. For example, bycatch reduction measures, including use of turtle excluder devices in shrimp trawlers, implemented in U.S. fisheries reduced overall accidental sea turtle deaths by 90 percent over two decades.
"The presence of sea turtles is a sign of a healthy ecosystem with a high level of biodiversity, which can support healthy fisheries," said Sebastian Troeng, Senior Vice President for the Global Marine Program at CI, who conducted his doctoral research on sea turtles. "This landmark study provides decision makers with a guide on how to prioritize bycatch prevention, which is a key component of sustainable fisheries management and absolutely necessary for global food security."