Using non-native shrimp as bait could be illegal and spread disease
As happens tens of thousands of times each year, a Texas angler walks into a bait shop, fishes a thin cardboard box or plastic bag holding a pound or so of frozen shrimp from the stack in the store’s freezer, pays for the bait and heads out for a day of relaxing recreation.
Maybe it’s to a beachfront pier or a stretch of bay shoreline where the angler plans to use the shrimp to tempt redfish, drum, whiting or other marine sport fish. Maybe it’s to a lake or river, where the shrimp will be used a bait for blue catfish.
As the angler opens the box or bag of bait shrimp, maybe he notices (but probably not) some small printing on the container noting the contents are a product of a country in Asia, Central America or South America. Farmraised shrimp. No surprise; as much as 90 percent of shrimp sold in this country are non-native species produced in foreign commercial shrimp farms. The frozen foreign shrimp are less expensive than fresh, never-frozen, wildcaught native shrimp, even if not nearly as effective as bait.
The angler threads one of the thawed shrimp on a hook, casts it into the water … unwittingly and certainly unintentionally violating a state law and potentially putting native crustaceans at risk of devastating diseases.
“It’s a situation most fishermen are not aware of, but one that puts fisheries at risk,” Lance Robinson, deputy director of coastal fisheries for Texas Parks and Wildlife Department, said of the sale and use of non-native, farm-raised shrimp as fishing bait. “We’re hoping to educate anglers and bait dealers about that very real risk so they can make informed choices.”
Against the law
Texas law classifies all Penaeid shrimp (marine shrimp) other than three species native to Gulf of Mexico waters (brown, white and pink shrimp) as “harmful or potentially harmful” and prohibits introducing them or any part of them into state-controlled waters.
Simply casting a hook baited with a non-native shrimp — even one long dead and frozen — into a bay, river or other public waterway is a violation of Texas law and could garner a Class C misdemeanor citation from a Texas game warden. Worse, it threatens to set loose two viruses deadly to shrimp, crawfish and other crustaceans into the ecosystem.
The prohibition on introducing non-native shrimp into Texas waters has two aims: preventing introduction of live alien species of shrimp into Texas marine waters, where they could become invasive species competing with native shrimp, and preventing the introduction of diseases carried by non-native shrimp. Both have the potential to devastate native crustaceans. And the second threat does not require the shrimp to be alive when it hits the water.
Foreign farm-raised shrimp are prone to outbreaks of several virus-caused diseases — a result of crowded and often unsanitary conditions in the aquaculture facilities. Two of the most common are “white spot syndrome virus” and “yellow head virus,” neither of which are native in Texas waters.
The viruses are easily transmitted from infected shrimp to other shrimp and can result in high and often complete mortality of shrimp held in grow-out ponds.
But foreign, non-native shrimp raised in farm operations can be infected with the disease and still live to be harvested and shipped to market.
Humans are immune to the viruses that cause the diseases in shrimp, so the presence of white spot or yellow head virus in shrimp poses no human health threat and does not disqualify shrimp from being sold for human consumption.
But the viruses are virulent to shrimp even after freezing.
“Freezing doesn’t destroy the viruses,” Robinson said. “The risk they pose to live shrimp is still there.”
That fact has been documented in multiple research projects. Researchers with the University of Arizona screened 10 different lots of farm-raised, non-native shrimp produced in foreign countries for the two viruses. They found shrimp in eight of the lots infected with white spot and three with yellow head viruses.
Researchers, under highly controlled conditions, exposed groups of live shrimp to the white spot virus collected from the frozen shrimp. In four of the nine bio-assays, 100 percent of the shrimp exposed to the viruses died.
More pointedly of concern to Texas fisheries managers and anglers, researchers with Texas A&M Veterinary Medical Diagnostic Laboratory and Texas Sea Grant/Cooperative Extension Service analyzed 20 boxes of frozen bait shrimp imported from China; shrimp in two of the boxes tested positive for white spot. The researchers also analyzed eight boxes of frozen native bait shrimp and found no viruses.
Concerns about the legality and potential risks of using imported, non-native shrimp as fishing bait have simmered for at least a couple of years. That concern was largely triggered when a federal law made it easier to determine packages of native shrimp from foreign-produced shrimp. A federal law that took effect in 2005 requires retailers inform customers of the country of origin of shellfish such as shrimp. That country of origin labeling is mandatory, even for bait shrimp.
Texas game wardens began noticing boxes of the frozen foreign shrimp, identifiable through that required country of origin labeling, being offered for sale at bait shops along the coast. The wardens, aware of the Texas law prohibiting introduction of non-native shrimp to public waters, addressed the issue with individual bait dealers. TPWD’s coastal fisheries division has mailed notices explaining the regulations and the threat posed by the non-native shrimp to all licensed bait dealers, Robinson said.
Easier to find
Bait vendors’ — and anglers’ — attraction to the frozen imported shrimp is understandable. The imported shrimp are much less expensive than wild-caught native shrimp, and they are more reliably available because of the boom in global trade. At least one bait dealer contacted by TPWD said he had an inventory of as much as 10,000 pounds of foreign shrimp; dumping that inventory would be economically ruinous to a small business.
“We heard from a lot of dealers,” Robinson said. Like anglers, most bait dealers have been unaware of the legal and environmental issues involved with using foreign-produced, non-native shrimp for bait.
“The risk is very real,” Robinson said of the threat posed should viruses carried by foreign shrimp be introduced into Texas waters and spread.
That risk is not limited to shrimp.
“The viruses infect crustaceans, and not just shrimp,” Robinson said. “Crawfish are susceptible, too.”
That means any anglers targeting catfish in an East Texas river or stream and using foreign shrimp carrying white spot virus for bait could potentially infect the waterway’s crawfish population. And crawfish are a crucial piece of the finfish forage base as well as whole freshwater ecosystems.
“Every time someone uses those shrimp as bait, it’s a risk,” Robinson said, noting TPWD plans to soon mount an information and education effort on the issue, aiming at anglers and bait dealers.
Robinson recommends anglers look closely at any box or bag of frozen shrimp they consider purchasing for bait. If it has a country of origin label indicating the shrimp are from a foreign country, don’t buy or use it. And if there is labeling, be wary.
“Ask those questions. Where are these shrimp from?” he suggests.
Fresh-dead or even frozen native, wild-caught shrimp are more expensive than the frozen foreign shellfish, but they also are a superior bait. And buying those wildcaught native shrimp supports the Texas commercial shrimpers, bait dealers and businesses who provide them to the state’s twomillion or more anglers.
Making certain the shrimp they buy and use as bait are native shrimp might cost anglers a little more, but if it reduced risks to the state’s fisheries (and the angler’s risk of a citation if found using prohibited shrimp), the benefits are well worth that cost.