First ever global study of the impacts of bycatch on turtles shows a worldwide crisis unfolding because of poor management of global fisheries.
Arlington, Virginia — Millions of sea turtles have become
the unintended victims of a failure to properly manage the worlds' fisheries,
with more and more of their habitats clogged with hooks and nets, an important
new report revealed today.
The report — the first ever global assessment of sea turtle bycatch in the
three major types of fishing gear: gillnets, longlines, and trawls — highlights
vast ocean regions where little about bycatch rates is known, and where urgent
conservation action to reduce bycatch is necessary to prevent the extinction of
these ancient, endangered animals.
The report, which appears this week in the journal Conservation Letters was
conducted by Conservation International (CI) in partnership with Duke
University's Project GloBAL (Global By-catch Assessment of Long-lived Species),
and clearly shows the links between increased fishing gear in regions and the
increase in accidental capture of sea turtles.
Bycatch occurs when fisheries use indiscriminate gear such as longlines with
thousands of baited hooks, or nets that inadvertently snag animals other than
what they are intended to catch. Sea turtles, along with sharks, dolphins, and
albatrosses, are among the most frequently accidentally captured. Air-breathing
reptiles, sea turtles often perish as a result of drowning in nets or swallowing
sharp J-shaped hooks which can become lodged in the soft tissue of turtles'
throats and stomachs, causing severe and often grave injuries.
In their report titled: "Global Patterns of Marine Turtle Bycatch",
Dr. Bryan Wallace of CI, and Dr. Rebecca Lewison of San Diego State
University, with several co-authors from Duke University's Center for Marine
Conservation, investigated the impact of bycatch on sea turtles around the globe
from 1990-2008. Their findings show that tens of thousands (~85,000) of marine
turtles have been reported as bycatch in the past twenty years, but Wallace and
colleagues stress that actual numbers are likely to be significantly higher.
Dr. Wallace, the Science Advisor for CI's Sea Turtle Flagship Program said:
"Because the reports we reviewed typically covered less than one percent of all
fleets, with little or no information from small-scale fisheries around the
world, we conservatively estimate that the true total is probably not in tens of
thousands, but in the millions of turtles taken as bycatch in the past two
Six of the seven marine turtle species are currently categorized as
Vulnerable, Endangered, or Critically Endangered globally by the International
Union of Conservation of Nature's (IUCN) Red List. They include loggerheads,
leatherbacks, hawksbills, Olive Ridleys, Kemp's Ridleys and green sea turtles;
the flatback, an endemic to Australia, is currently categorized as Data
Sea turtles are highly migratory animals that cover vast areas of ocean
between nesting and feeding grounds, traveling thousands of miles each year and
traversing international boundaries. Their broad distributions expose them to
several threats, including directed capture for their meat and collection of
eggs, destruction of nesting beaches, pollution of the ocean, and climate
change. However, bycatch is the most serious, acute threat to sea turtle
populations around the world.
The global data review revealed that the highest reported bycatch rates for
longline fisheries occurred off Mexico's Baja California peninsula, the highest
rates for gillnet fishing took place in the North Adriatic region of the
Mediterranean and the highest rates for trawls were found off the coast of
However, when bycatch rates and amounts of reported fishing activity for all
three fishing gear types were combined and compared, four regions emerged as the
overall most urgent conservation priorities: the Mediterranean, the Eastern
Pacific, the Southwest Atlantic, and the Northwest Atlantic.
In the Mediterranean Sea, where more than 20 countries fish in the same ocean
basin for species like bluefin tuna and swordfish, a lack of integrated
management has led to some of the highest concentrations of longline fishing and
trawling around the globe, and consequently, some of the highest sea turtle
bycatch rates in the world.
In the Eastern Pacific — which stretches from Baja California, to Patagonia,
Chile and hosts critical nesting and breeding grounds for the leatherback and
Olive ridley sea turtles — populations of leatherback and hawksbill have nearly
collapsed, owing in part to bycatch in large and small-scale fisheries which
deploy large numbers of longlines, gillnets and shrimp trawls in both the
high-seas and near shore.
Other regions highlighted as urgent conservation priorities in the report
include the Southwest Atlantic and Northwest off the eastern
United States, home to one of the world's largest loggerhead turtle populations,
but where high numbers of longline and trawl fisheries also contribute to high
incidents of bycatch.
"We have only begun to scratch the surface about the realities of sea turtle
bycatch," said study researcher Dr. Wallace. "Our review revealed important data
gaps in areas where small-scale fisheries operate, especially Africa, the
eastern Indian Ocean and Southeast Asia. These regions and fisheries are urgent
priorities for enhanced monitoring and reporting effort so that we can fill in
some blanks about turtle bycatch."
To lower sea turtle bycatch rates, and improve overall ocean health,
Conservation International's Global Marine Division has recommended several
- Regional governance: establish Marine Protected Areas
similar to those CI has successfully supported in the Eastern Pacific Tropical
Seascape (ETPS) and Bird's Head and Sulu Sulawesi Seascapes of Indonesia.
- Sustainable fisheries reform: including seasonal and
time-area closures to control fishing activity in turtle migration areas as well
as catch-shares, which place quotas on fishing efforts and reduce the race for
- Selective gear modification: the continued use of circle
hooks, as well as the widespread implementation of Turtle Excluder Devices
(TEDs), which serve as escape hatches for sea turtles caught in shrimp
- Responsible seafood consumption: Consumers are encouraged
to use wallet guides (available from the Blue Ocean Institute and others) and
resources like FishPhone, to learn more about turtle-friendly seafood
Coordinated implementation of these strategies will have dramatic effect on
the viability and persistence of our oceans and of sea turtles, because they,
like other large, highly migratory, charismatic marine animals, are bellwethers
of ocean health.
"Sea turtles are sentinel species of how oceans are functioning. The impacts
that human activities have on them give us an idea as to how those same
activities are affecting the oceans on which billions of people around the world
depend for their own well-being." said Dr. Wallace. "Our hope is that this study
gives governments and fisheries alike another impetus for bolstering on-going
efforts to reduce sea turtle bycatch and to promote more sustainable fishing
practices as soon as possible."
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Sea Turtle Photos for use by Media:
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For media inquiries and more information please
Patricia Yakabe Malentaqui, Manager, International Media (Latin America)
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For Duke University:
Notes to the editors:
Conservation International (CI): Building upon a strong
foundation of science, partnership and field demonstration, CI empowers
societies to responsibly and sustainably care for nature for the well-being of
humanity. With headquarters in Washington, DC, CI works in more than 40
countries on four continents. For more information, visit www.conservation.org.
Duke University Center for Marine Conservation: an
interdisciplinary consortium at Duke's Nicholas School of the Environment
focusing on research, education, and outreach in marine conservation. Project
GloBAL (Global Bycatch Assessment of Long-lived Species) is a joint venture
between Duke and Blue Ocean Institute that aims to characterize the bycatch of
marine mammals, seabirds, and sea turtles.
Blue Ocean Institute Fishphone & Wallet Guides: Blue
Ocean Institute uses science, art, and literature to inspire a closer bond with
nature, especially the sea. To request a free seafood wallet guide from anywhere
in the world, visit: www.blueocean.org. Within the continental
U.S., FishPhone is Blue Ocean's sustainable seafood text messaging service that
instantly puts sustainable seafood information at your fingertips. To find out
about your seafood choice, text 30644 with the message FISH and the name of the
fish in question.