Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Small-scale fishing in Mexico rivals industrial fisheries in accidental turtle deaths

17.10.2007
Local fishing villages band together to change practices and preserve loggerhead turtles

Industrial fishing operations take plenty of blame for both depleting fish stocks and inadvertently catching innocent bystanders such as dolphins, sharks, seabirds, and sea turtles--a phenomenon known as "bycatch."

But new research shows that a small-scale Mexican fishery--operated by hand from small open boats--can kill as many critically endangered loggerhead sea turtles as all of the industrial fishing fleets in the North Pacific Ocean put together. On a per-hook or per-net basis, the Mexican fishery is 10 to 100 times as deadly, the study found. The research has already resulted in a voluntary turnaround in the fleet's fishing practices and the declaration of an offshore turtle refuge.

"The impacts of small-scale fisheries have been overlooked because they are inherently difficult to study," said lead author Hoyt Peckham, a Ph.D. candidate in ecology and evolutionary biology at the University of California, Santa Cruz.

Peckham and colleagues worked alongside Mexican fishermen to simultaneously measure and reduce the accidental turtle catches. Their findings suggest that small fishing operations, which are ubiquitous along coastlines the world over, can have drastic, unintended effects on ocean wildlife such as sea turtles. The work appears in the October 17 edition of the online, open-access journal PLoS ONE.

"It was really surprising to me, because when I think of bycatch I think of massive factory trawlers with huge catch rates decimating the oceans," Peckham said. "What's striking in this work is that some small-scale fleets can kill many more turtles, because they fish where turtles are most abundant."

One such place is off the coast of Baja California Sur, Mexico, where perennially rich turtle feeding waters overlap with a small patch of favored fishing grounds. Local fishermen ply these waters for halibut and other bottom-dwelling fish using gill nets and strings of hooks known as longlines. Their pangas--small boats around 20 feet long--usually fish within about 3 miles of shore, where there are few turtles. But when the fishermen venture farther offshore they share the water with thousands of turtles that spend decades fattening up on the abundant food.

Many turtles are snared inadvertently. Peckham and his coworkers estimated the bycatch at more than 1,000 turtles per year based on their observations accompanying fishermen on day trips and surveying local beaches for washed-up turtle carcasses. Bycatch happens so commonly, Peckham said, that many locals at first didn’t even realize the turtles were endangered.

By comparison, U.S. officials are so concerned about loggerhead turtles that in 2002 they shut down Hawaii's 20-boat, $55 million swordfish fleet to develop ways to avoid bycatch. The fishery reopened three years later but included an automatic cap that shuts down the season if the fleet as a whole hooks more than 17 turtles. In 2006, the cap was reached just three months into the 10-month season, Peckham said.

Loggerheads are medium-sized sea turtles whose shells reach about a meter (3.3 feet) in length. They live for 50 years or more and nest on beaches in many parts of the world, including the southeastern U.S., the Mediterranean, Oman, Australia, and Japan.

North Pacific loggerheads nest exclusively in Japan, where records from the past 50 years show they are plunging toward extinction. At some nesting beaches, numbers have dropped 50 percent to 90 percent in the last decade. Fewer than 1,500 adult females are thought to nest each year in the entire North Pacific, according to Peckham.

But in addition to those adults, there are many thousand adolescent turtles that spend several decades roaming the North Pacific--and feeding in the waters off Baja California--before beginning to breed. Losing 1,000 or more per year in Mexican waters alone is likely to put a dent in breeding numbers that will be felt decades into the future.

"You can protect hatchlings on beaches all you want, but if you don't protect juveniles during those 30 years on their foraging habitats, it's never going to work," Peckham said.

After realizing the scale of the bycatch, Peckham planned his dissertation research in a way that would help solve the problem. Through the regional conservation network Grupo Tortuguero, he employed Mexican high school and university students to go out on fishing boats and record turtle catches. He set up meetings with local fishermen to brainstorm ways to avoid the problem, including testing alternative fishing gear, bringing Japanese and Hawaiian fishermen to Mexico to share oceanwide perspectives, and spreading the word about bycatch through comic books, impromptu movie showings, murals, and festivals. (See related story at http://press.ucsc.edu/text.asp"pid=1597.)

After seeing the global consequences of their activities, the fishermen quickly made strides to curb their fleet's impact. Last year, a traditionally rich fishing locale that also produced much of the turtle bycatch was voluntarily made into an off-limits "Fishers' Turtle Reserve" by the fishermen themselves. Efforts to declare the area an official national reserve with legal protection are under way. And earlier this year, Peckham said, the owner of the area's biggest fishing fleet chose to retire his longlines from duty in turtle-rich waters.

"In the realm of saving ocean wildlife, we rarely see opportunities as powerful as this," said Wallace J. Nichols of the Ocean Conservancy, a coauthor of the paper.

"These Mexican fishermen are bringing about probably the biggest reduction in bycatch by any single action that we can imagine. That fleet's switch away from bottom-set longlines will spare hundreds of loggerheads a year," Peckham said.

Hugh Powell | EurekAlert!
Further information:
http://www.ucsc.edu

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

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: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Solar Collectors from Ultra-High Performance Concrete Combine Energy Efficiency and Aesthetics

16.01.2017 | Trade Fair News

3D scans for the automotive industry

16.01.2017 | Automotive Engineering

Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs

16.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>