2007 Runner-Up Prize Winners ($10,000 each)
© Glenn R. Parsons
Close up of the Nested Cylinder Bycatch Reduction Device.
The Nested Cylinder - Dr. Glenn Parsons, University of Mississippi
DESIGN OF THE NESTED CYLINDER
The Nested Cylinder Bycatch Reduction Device was designed to reduce the bycatch of juvenile red snapper in the Gulf of Mexico shrimp trawl fishery.The innovative device is made up of two sleeves - a small cylinder nested inside a larger outer cylinder on the downstream end.
The small cylinder is painted white on the inside and is brightly illuminated; the large cylinder is painted black. The device is attached inside a trawl to generate a continuous escape opening around the circumference of the net.
When dark-adapted fish like red snappers find themselves in the brightly illuminated environment of the small cylinder and are presented with the seeming refuge of the darkened large cylinder, they instinctively swim through the larger cylinder, through the escape opening, and out of the trawl.
To further guide unwanted finfish out of the trawl, flow-blocking panels are placed upstream of the escape opening, creating flow shadows. Fish take hydrodynamic refuge in these slow-flow areas, and in doing so find themselves on the outside of the net.
The potential for this device to reduce bycatch and subsequent mortality of juvenile red snapper is significant - a cleaner catch and greater profit for the shrimper is a win-win situation for the marine environment and the fishing industry.
Dr. Glenn R. Parsons, designer of the Nested Cylinder
© WWF-Canon / Edward Parker
Giant Shrimp, Gulf of California, Mexico.
© Courtesy of Glenn R. Parsons
Bycatch Reduction Device during field testing.
FIELD TESTS OF THE NESTED CYLINDER
Field testing was carried out in the northern Gulf of Mexico using a parallel towing technique. Initial sampling aboard a National Marine Fisheries Service research vessel showed an average 41 percent bycatch reduction. Field tests were then conducted aboard the working shrimp vessel R/V Simple Man, where results indicated an average 55 percent bycatch reduction.Further, an 81 percent shrimp retention was obtained in the nets equipped with the device - and a 91 percent retention where haulback was closely monitored.
Positive responses from the crew aboard the R/V Simple Man are evidence that the nested cylinder design - a cost-effective device that is simple to install and requires low maintenance - will likely be well-received by fishermen.
THE WINNER
Dr. Parsons has spent almost 30 years conducting fish and fisheries research in the Gulf of Mexico and the Atlantic Ocean. He is a professor of biology at the University of Mississippi.
For the past five years Dr. Parsons has been immersed in bycatch reduction research. He has worked closely with both recreational and commercial fishers throughout Alabama, Florida and Mississippi. His most recent major contribution was the publication of the book Sharks, Skates and Rays of the Gulf of Mexico: A Field Guide. He is donating the book's royalties to Hurricane Katrina relief funds.