Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Building a better fish trap: WCS reduces fish bycatch with escape gaps in Africa

08.10.2013
New basket traps designed by WCS and Kenyan Marine and Fisheries Research Institute allow juvenile and non-target fish species to escape while increasing incomes

Scientists from the Wildlife Conservation Society and the Kenyan Marine and Fisheries Research Institute have achieved a milestone in Africa: they've helped build a better fish trap, one that keeps valuable fish in while letting undersized juvenile fish and non-target species out.


A trap fisher modifies an African basket trap with escape gaps. Researchers from WCS and the Kenyan Marine and Fisheries Research Institute have found that escape gaps trap market-sized fish while allowing undersized and non-target fish to escape. According to a recent study, escape gaps help protect marine resources while boosting profits for fishing communities.

Credit: Ines Gomes

By modifying conventional African basket traps with escape gaps, the marine researchers have proven that the new traps catch larger fish, allow more undersized and non-target fish to escape, increase profits, and—most importantly—minimize the impact of fishing on coastal reef systems. The findings, say researchers, will help fishing communities boost profits while protecting their vital marine resources.

A paper on the experimental study appears in the current edition of Fisheries Research. The authors include E.K. Mbaru of the Coral Reef Conservation Project and the Kenyan Marine and Fisheries Research Institute; and Tim McClanahan of the Wildlife Conservation Society.

"One of the great challenges in coastal fisheries is how to reduce the levels of bycatch for reef systems where these species play important ecological roles," said Dr. Tim McClanahan, co-author of the study and head of WCS's coral reef research and conservation program. "Our modified traps have made a statistically measurable difference in minimizing bycatch for African basket traps. Such innovations can make a big difference in maintaining the ecology of vital coastal resources."

The experimental study was conducted in the fished reef systems near a marine park on the coast of Mombasa, Kenya. Importing the escape gap idea to African waters for the first time, the researchers worked with an experienced trap fisher who built six basket traps—iron-framed structures with netting and a single, tube-shaped opening leading into the middle of the trap. Half of the traps were constructed with escape gaps measuring 12 inches by an inch and a half. The escape gaps were designed to allow undersized and non-target fish to exit while retaining commercially valuable adult fish.

Once baited, the traps were deployed some 30 meters apart and between 5 and 10 meters in depth and checked once a day between October 2010 and October 2011. After 41 weeks, the researchers captured more than 1,200 fish from 64 species. The fish captured in the experimental traps were on average 31 percent longer and 55 percent heavier than fish in the regular traps without gaps (used for control data). By contrast, the regular traps had smaller fish, including the juvenile and ornamental fish important for maintaining reef ecology. The researchers also reported a 25 percent increase in economic value in the fish captured in the escape-gap traps, mostly valuable rabbitfishes.

The escape-gap traps also allowed smaller non-target fish to escape. Of the fish caught in the escape-gap traps, only 34 individual fish belonging to "bycatch" species (or 2 percent) remained in the traps, as opposed to 110 individuals (or 6 percent of the catch) from non-commercial species in the regular traps.

"These new escape gaps are a game changer for Kenya's coastal fisheries," said Dr. Caleb McClennen, Director for WCS's Marine Programs. "By reducing bycatch, the new basket traps increase fish size, economic return, while limiting the bycatch that can harm entire reef systems. These innovations can also be exported to other coastal fisheries for the benefit of entire regions."

The escape gap design for African basket traps—created by McClanahan and his WCS colleague Ayana Elizabeth Johnson—received top prize and $20,000 in support for conservation in the 2012 Solution Search: Turning the Tide for Coastal Fisheries, an award created to bring recognition to innovative community-based conservation projects.

This study was made possible through the generous support of The Tiffany & Co. Foundation and the John D. and Catherine T. MacArthur Foundation.

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

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: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

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....

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

Underwater acoustic localization of marine mammals and vehicles

23.11.2017 | Information Technology

Enhancing the quantum sensing capabilities of diamond

23.11.2017 | Physics and Astronomy

Meadows beat out shrubs when it comes to storing carbon

23.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>