Gafftopsail Catfish Consumption Advisory in Sabine Lake

FREQUENTLY ASKED QUESTIONS - December 2011

What are PCBs?
PCB’s (polychlorinated biphenyls) are a family of organic compounds that have been widely used since 1929 as coolants and lubricants in electrical equipment (transformers, capacitors, etc.) because they don’t burn easily and are good insulators.  There are no known natural sources of PCBs.  Over 1,200,000 tons of PCBs were manufactured in the United States.  Of this, about 65% is still in use, 31% is an environmental burden, and 4% has degraded or been incinerated.  PCBs are stable compounds, are long-lived in the environment, and can be found everywhere.  Concern over toxicity and persistence in the environment led Congress in 1979 to prohibit the manufacture, processing and distribution of PCBs. 

How Do PCBs Affect People?
PCBs have been found in soil, ground and surface water, air, sediment, plants, and animals in all regions of the world.  PCBs break down very slowly in the environment and accumulate in fatty tissue, skin, and internal organs of fish and other animals.  The amount of PCBs found in fish varies with species, age, size, fat content, diet, and surface water concentrations.  Larger, older fish will generally contain higher levels of PCBs than lean fish.  Eating fish that contain PCBs may cause infants of women who have eaten many contaminated fish to have lower birth weights, delayed physical development, and learning difficulties.  PCBs may affect the immune system, reproductive organs, skin, stomach, thyroid, kidney, and liver and may increase the risk of cancer.  The types of PCBs that tend to concentrate in fish and bind to sediments happen to be the most carcinogenic components of PCB mixtures. 

Why Would Gafftopsail Catfish Show High Levels of PCBs?
Once PCBs have entered into an animal’s body they get stored in fat tissue.  This makes it hard for the organism to eliminate them from its body.  As you move up the food chain the PCB compounds begin adding up (biomagnification).  While animals do eliminate them slowly from their bodies, their physiological systems may not be able to keep pace with the concentration in the environment.  Thus some individuals begin accumulating concentrations that pose a risk to humans (or other predators).  Predators that are at the top of the food web are going to accumulate the greatest concentrations.  It is important to note that not all animals are the same at accumulating PCBs.  Factors such as growth rate, dietary preferences, migration habits, etc. play a role in determining the concentration that accumulates in the body.

What is the source of the PCBs in Gafftopsail Catfish?
At this time a specific source of PCBs in Sabine Lake is unknown.  Because PCBs were once commonly used there are many potential sources.  They take a long time to degrade or breakdown and they exist in the environment typically at very low concentrations.  PCBs can be found in the sediments, rainfall runoff, in leaching water from buried equipment or landfills, inflow from contaminated tributaries, and atmospheric deposition.  PCBs persist for many years in the environment.  Thus pollution sources from decades ago may still be present and having effects now. 

How Much of Sabine Lake Is Affected By the Advisory?
The Texas Department of State Health Services (DSHS) has issued an advisory recommending limited consumption of gafftopsail catfish from all Texas waters of Sabine Lake including all contiguous Texas waters.

What About Gafftopsail Catfish Caught Outside the Advisory Area?
Since gafftopsail catfish readily move within a bay system, one potential source of public concern is how extensive the PCB problem is within areas adjacent to the advisory area of Sabine Lake.  The DSHS study did not include samples beyond Texas state waters in Sabine Lake.  The Louisiana Department of Wildlife and Fisheries (LDWF) has been notified of the Texas Department of State Health Services findings.

Are Other Game Fish Species Affected?
Sampling conducted by the Texas Department of State Health Services in 2010 included samples from other species, including spotted seatrout, red drum, black drum, southern flounder, sand trout and alligator gar.  However, only catfish showed elevated levels of PCBs that would be cause for concern.  This is most likely due to different rates of metabolism between species, age, size, fat content, diet and seasonal behavioral patterns.

What Should People Do?

  1. Anglers can play an important role in helping to spread the word about fish consumption advisories within the fishing community.  Catch and release fishing is already a preferred practice of many anglers, and it is a way to minimize risk since no fish is consumed.  Since PCBs readily accumulate in the fatty tissues of fish, anglers can reduce exposure to these chemicals by removing the skin, dark (reddish-color) muscle tissue, and fatty portions (i.e. belly fat, side fat, and fat along the top of the back) before cooking.  The Texas Department of State Health Services recommends baking or broiling skinned, trimmed fish on a rack or grill to allow fat to drip away from the fillet.  If fish are fried, the frying oil should not be reused.  These cooking methods will reduce exposure to many of the most common organic chemical contaminants in fish, including PCBs. Additional information about preparing fish for consumption can be found at http://www.dshs.state.tx.us/seafood/eatrisk.shtm and http://www.atsdr.cdc.gov/HAC/PHA/oakridge013107-TN/appc3.pdf.

What is the likely effect of the advisory on fishing?
This advisory may have some affect on fishing in Sabine Lake and on some associated businesses. Gafftopsail catfish are a popular food fish in Texas. Anglers who wish to take fish home,following the handling recommendations from DSHS will reduce an angler’s exposure to PCBs that might be present in fatty tissues. Additionally, there are many other species available to fishermen including spotted seatrout, red drum, flounder, sand trout, black drum, and whiting, to name a few.

 


For more information about how PCBs affect fish and fisheries, contact:
  • Lance Robinson, Coastal Fisheries Division, Texas Parks and Wildlife Department, Dickinson Marine Laboratory, (281) 534-0101; lance.robinson@tpwd.state.tx.us
  • Jerry Mambretti, Coastal Fisheries Division, Texas Parks and Wildlife Department, Port Arthur Field Station, (409) 983-1104 (ext. 222); jerry.mambretti@tpwd.state.tx.us
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