TPWD News Release — July 12, 2004
Many restaurants now offer a wide variety of piscatorial platters, including some of the more popular species of game fish, such as red drum, channel catfish and hybrid striped bass. Commercial aquaculture operations from Texas and throughout the world make available an even wider array of farm-raised game fish, including red snapper, flounder, grouper, catfish and even largemouth bass. Although in Texas, like most states, it is illegal to sell wild game fish; commercial fish farms are able to produce these species for sale and consumption.
It would be almost impossible to tell a farm-raised bass from a wild fish once it’s been pan-seared in butter and topped with an orange-basil cream sauce, but it can be done before it hits the skillet, according to the Texas Parks and Wildlife Department.
TPWD game wardens monitor commercial fish markets to ensure the product they sell is not the product you catch and the agency law enforcement forensic specialist confirms the product source through laboratory analysis.
"Fish are what they eat," explained Beverly Villarreal, the forensic specialist with TPWD’s Law Enforcement Division. "I can tell whether they are wild caught or farm-raised by analyzing the fatty acids in the muscle tissue of these fish.
Back in the ’80s during the blackened redfish craze started by Cajun chef Paul Prudhomme, fisheries resource managers in Texas were concerned that declining red drum stocks may have been the result of overharvest by commercial fishermen trying to meet the demands of seafood restaurants. To make their case, law enforcement officials needed a way to differentiate a farm-raised red drum from one taken in the wild. They turned to science for help.
Villarreal, then a graduate student in aquatic biology at Texas State University, found the answer. In her thesis work based on hybrid striped bass tissue analysis research conducted by the National Marine Fisheries Service, Villarreal was able to identify distinctive "markers" in muscle tissue fatty acids that distinguished between red drum produced at aquaculture facilities and native wild fish.
"The premise was the protein sources used in commercially-prepared diets are made up of terrestrial components, including soy, corn and wheat," Villarreal said. "Associated with those sources are the oils of the plants, which give a very different profile than what’s consumed out in the marine environment. It held true no matter what kind of fish."
As a result of her work, game wardens were able to clean up the red drum market. Because the analysis could be used on other species, too, the tests have become a valuable tool for game wardens.
"Most of the larger cases involving wild versus farmed fish forensic analysis has been for undercover law enforcement cases, but field game wardens do monitor what goes on in the commercial fish market," said Villarreal.
According to Bill Robinson, chief of fisheries enforcement with TPWD, game wardens keep a watchful eye for violators. "We get tips from concerned citizens who tell us about seeing game fish on display in restaurants and fish markets and we investigate," he noted. "We got a call from Louisiana officials recently who seized several boxes of black bass they said originated from a fish dealer in Texas. It’s illegal to sell black bass in Louisiana regardless if they were commercially produced or not."
Game wardens submitted samples of the black bass in question to the TPWD lab in San Marcos. After a fatty acid muscle tissue test by Villarreal, the results confirmed that the fish were raised in an aquaculture environment and fed the prepared feed.
Robinson said instances where wild fish are being passed off as commercially grown are rare these days and TPWD will continue to monitor the industry to ensure compliance.
Anyone smelling something fishy at the market or on the menu is encouraged to contact their local TPWD law enforcement office or call the Operation Game Thief hotline toll free (800) 792-GAME.