TRAWLING FOR ANSWERS
Researchers dive for clues to improve fish populations.
Written by Scott Slemmons
No one ever said shrimping was easy.
Shrimpers trawl for hours at a time. A good day will bring a net full of shrimp that pays for crew, fuel and dock fees and puts food on the table. A not-so-good day fetches what’s known as a by-catch: a net full of fish too weak to escape the nets and too young to sell—along with a very small number of shrimp that won’t begin to pay costs. Many days fall into the latter category.
The government requires new nets that will make it easier for fish to escape the trawls. But these also make it easier for shrimp to escape. So fishermen tinker with the design to make it harder for the shrimp to get out of the nets. This makes it harder for the fish to get out too. Which puts many fisherman back in the same situation they were in before. 
So shrimpers are not catching enough shrimp. Other fishermen are angry because shrimpers are reducing their own catches of other fish species. The government keeps pushing new net designs on them.
Can this situation be fixed?
Possibly.
Sandra Diamond, assistant professor of biology at Texas Tech, says the key may lie less with new net designs and more with dispensing better information about where to trawl.
“We’ve been putting together a comprehensive survey of the marine life on the Gulf Coast,” says Diamond. “Once that’s done, we can put our data into a GIS (Geographic Information Systems) computer mapping program and print out maps that will let fishermen know where we think the best fishing will be throughout the year. If they want to know where to trawl in August, we’ll have a map that’ll say what areas should have the most shrimp. If they want to know where to trawl in October, December, March, whenever, we’ll have the data and a map that should help them.”
Diamond normally centers her research on populations of red snapper in the Gulf, but large by-catches of red snapper and other fish gave her the opportunity to broaden her focus.
“Red snapper is only one of about 150-200 species accidentally caught in shrimp trawls,” Diamond says. “You can get four to 10 non-target species in a trawl for every shrimp in the net.”
Diamond and co-workers make maps based on data collected by the National Marine Fisheries Service. Since 1972, the service has trawled twice a year from a research boat. The Texas Tech team is trying to use this data to find hot spots for shrimpers. But there’s more to the work than just plugging numbers into a computer. Diamond and her fellow researchers make frequent trips to the Gulf Coast, where they ride along on shrimp boats and scuba dive to check on marine populations.
The group has been given permission to attach fish cages underneath three oil platforms owned by BP about 30 miles off the coast of Port Aransas. The cages hold a small population of red snapper and other fish to study. Diamond and others scuba dive to check these fish for growth rates and mortality. They want to translate what they find into ways to improve fish populations.
“I think we can improve things to the benefit of everyone,” says Diamond. “It’ll take time and effort on everyone’s part, but I think we can get it done.”
Story produced by the Office of Communications and Marketing,
806-742-2136
Photos by Neal Hinkle and Sandra Diamond
Web layout by Jon Fox