Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Declining catch rates in Caribbean green turtle fishery may be result of overfishing

17.04.2014

20-year study finds large decrease in green turtle catch rates

A 20-year assessment of Nicaragua's legal, artisanal green sea turtle fishery has uncovered a stark reality: greatly reduced overall catch rates of turtles in what may have become an unsustainable take, according to conservation scientists from the Wildlife Conservation Society and University of Florida.


A green turtle is being unloaded by fishers in Río Grande Bar community. A 20-year assessment of Nicaragua's legal, artisanal green sea turtle fishery by the Wildlife Conservation Society and the University of Florida has uncovered a stark reality: greatly reduced overall catch rates of turtles in what may have become an unsustainable take.

Credit: Photo by Cathi L. Campbell

During the research period, conservation scientists estimated that more than 170,000 green turtles were killed between 1991 and 2011, with catch rates peaking in 1997 and 2002 and declining steeply after 2008, likely resulting from over-fishing. The trend in catch rates, the authors of the assessment results maintain, indicates the need for take limits on this legal fishery.

The study now appears in the online journal PLOS ONE. The authors are: Cynthia J. Lagueux and Cathi L. Campbell of the University of Florida (formerly of the Wildlife Conservation Society), and Samantha Strindberg of the Wildlife Conservation Society.

"The significant decrease in the catch rates of green turtles represents a concern for both conservationists and local, coastal communities who depend on this resource," said Dr. Lagueux, lead author of the study. "We hope this study serves as a foundation for implementing scientifically based limits on future green turtle take."

Caribbean coastal waters of Nicaragua contain extensive areas of sea grass, principal food source for green turtles, the only herbivorous sea turtle species. Green turtles in turn support a number of indigenous Miskitu and Afro-descendent communities that rely on the marine reptiles for income (by selling the meat) and as a source of protein.

The catch data used by the researchers to estimate trends was gathered by community members at 14 different sites located in two geographically political regions of the Nicaraguan coast. The research team analyzed the long-term data set to examine catch rates for the entire fishery, each region, and for individual turtle fishing communities using temporal trend models.

Over the duration of the assessment, the scientists recorded that at least 155,762 green turtles were caught; the overall estimated catch (factoring in estimated take during periods when data were not recorded) was 171,556 turtles. The average catch rate per fishing trip (assuming average fishing effort in terms of nets used and trip length) revealed an overall decline from 6.5 turtles to 2.8 turtles caught, representing a 56 percent decline over two decades.

In individual communities, catch rate declines ranged between 21 percent and 90 percent in green turtles caught over the 20-year period.

"These declining catch rates align with our survival rate estimates of green turtles exposed to the Nicaragua turtle fishery and population modelling, which suggested the fishery was not sustainable at high take levels reported in the 1990s," said Dr. Cathi Campbell.

The steep declines in green turtle catch rates, the researchers maintain, indicate a potential decline of green turtle populations that use Nicaragua's foraging grounds, particularly smaller rookeries in the Caribbean. The scientists note that the study results highlight the need for not only close monitoring of rookeries in the region, but also in-water aggregations of green turtles. Further, future research efforts should include the use of molecular technology to better refine Caribbean green turtle genetic stocks, specifically to identify populations most at risk from turtle fisheries.

"Given the importance of green turtles to Nicaragua's past, present and future, we encourage the communities, governmental agencies, and conservation groups to take measures that conserve and sustain these globally threatened populations, and to work together to ensure that the communities have alternative sources of protein and income into the future," said Dr. Caleb McClennen, Director of WCS's Marine Program.

Growing up to 400 pounds in weight, the green turtle is the second largest sea turtle species next to the leatherback turtle. The reptile inhabits the tropical and subtropical waters of the world. The species is listed as Endangered on the IUCN's Red List and on CITES (Convention on International Trade in Endangered Species of Wild Flora and Fauna) as an Appendix I species, a designation which prohibits all international commercial trade by member countries. In addition to the threat from overfishing (intentional take), the green turtle is at risk from bycatch in various fisheries (unintended take), poaching of eggs at nesting beaches, habitat deterioration and loss due to coastal development and climate change effects, and pollution.

John Delaney | Eurek Alert!
Further information:
http://www.wcs.org

Further reports about: Caribbean Conservation Declining Wildlife fishery fishing green turtles populations turtle fishing

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>