Modified gear could increase shrimp catch by 10 percent, limit bycatch

April 03, 2012

By Jim Hiney

COLLEGE STATION, Texas — A small portion of Texas’ commercial shrimping fleet will begin trawling state and federal waters 30 minutes after sunset on Sunday with modified gear that could increase their catch by as much as 10 percent while limiting the amount of unwanted species caught to federally acceptable levels.

For an industry that frequently operates on a razor thin margin between profitability and going out of business, 10 percent represents a very significant economic impact, says Gary Graham, Fisheries Specialist with the Texas Sea Grant College Program, who was instrumental in developing and testing the equipment.

“If you’re talking about a boat that grosses $300,000 to $400,000 per year, then they are looking at grossing $30,000 to $40,000 more,” Graham said. “That’s a huge amount to them.”

The Gulf of Mexico commercial shrimp season for both state and federal waters off the Texas coast closes for about two months, between May and July, every year to protect brown shrimp during their major period of emigration from nursery grounds in the bays to the Gulf of Mexico. This closure, which extends from shore out 200 nautical miles, allows the shrimp to reach a larger, more valuable size before they are harvested.

Federal regulations require that shrimp boats have bycatch reduction devices (BRDs) installed in their nets. Bycatch is the common term applied to sea life other than shrimp that wind up in shrimp nets.
There are currently four types of BRDs approved for use, but the majority of shrimp fishermen use a type called a “fisheye” because it is least expensive. A fisheye is a metal framework that keeps a hole in the net open so fish can swim out. Its drawback is that it also allows 10-15 percent of the shrimp that enter the net to escape, Graham says.

“Shrimp lost from the net equals money lost for the fisherman,” says Tony Reisinger, Texas Sea Grant’s Cameron County Coastal and Marine Resources Agent, who has helped Graham in his gear work for the past 30 years.

For the first time this year, about 80 boats will use a “modified composite” BRD. As Graham explains it, a composite BRD acts like a funnel within the net. “Imagine water rushing through this funnel and off to the sides there is quiet water. Fish will seek the quiet water and that’s where there are holes in the net to let them escape.”

Composite BRDs have been around for several years but they were never fully certified because they failed to reduce bycatch by at least 30 percent — the threshold mandated by the federal government for fully certified BRDs. Composite BRDs achieved 30 percent reduction after they were modified to include a patch of netting with larger square mesh. The larger mesh measures between three and four inches square. By comparison, the netting surrounding the patch is generally diamond shaped with sides measuring a little less than two inches. The larger mesh is sewn into the nets behind the composite BRD and offers another escape route for trapped fish. Preliminary data suggests that the modified composite BRD reduces shrimp loss to somewhere between 2 percent and 5 percent.

Fisheye BRDs cost about $20 each while the modified composite BRDs cost about $130 each. Fishermen can quickly make back the cost of the more expensive BRD because more shrimp remain in the nets. Should the modified composite BRD perform as expected, many more shrimp fishermen will most likely adopt the gear.

“Shrimpers don’t like to catch fish,” Reisinger says. “The less bycatch you have on deck, the quicker you can work through your catch, which helps you keep your shrimp in a good quality condition, plus you are helping the environment by not taking a lot of fish.”

Pictured:

Inside view of a shrimp net with a composite BRD. Photo courtesy NOAA

Texas Sea Grant College Program Fisheries Specialist Gary Graham (foreground) measures the angle of a turtle excluder device in a shrimp net aboard a boat in Brownsville to confirm it complies with federal regulations. Photo by Tony Reisinger, courtesy Texas Sea Grant.

Larger mesh netting sewn into shrimp net. Photo by Tony Reisinger, courtesy Texas Sea Grant.
 

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Texas Sea Grant is a unique partnership that unites the resources of the federal government, the State of Texas and universities across the state to create knowledge, tools, products and services that benefit the economy, the environment and the citizens of Texas. It is administered through the National Oceanic and Atmospheric Administration and is one of 33 university-based Sea Grant Programs around the country. Texas Sea Grant is a non-academic research center in the College of Geosciences at Texas A&M University. The program’s mission is to improve the understanding, wise use and stewardship of Texas coastal and marine resources.