Four Things You Hate to Think about When You Fish

Barbara Gregg, Ph.D. Coastal Fisheries Division, Austin Tx

About the last thing anyone wants to think about when they’re fishing is whether or not the water has vibrio or red tide, if the dead fish floating were caused by a chemical spill, or whether or not the fish you catch is okay to eat. To find out, you usually have to wait until you get back to the marina or bait shop or maybe the internet at home. Even then you may not know who to ask. The following few paragraphs will give you a chance to get some answers before you start your trip.

VIBRIO: Vibrio infections have been reported in Texas for many years. Vibrio vulnificus , which causes skin ulcerations, fever, etc. from contacted from infested seawater and which causes vomiting, diarrhea, abdominal pain, and death from eating eating raw or undercooked infected shellfish. In fact, last year Texas had 43 diagnosed Vibrio infections and seven deaths. This year hasn’t been any worse than previous years, but has received more attention and questions, including a GCC article about Vibrio vulnificus last month.

The Vibrio bacteria live in coastal waters around the world and are usually more prevalent in summer months when the waters are warmer. There are really two main things to remember: 1. Don’t come in contact with any coastal, bay, or Gulf waters if you have open sores or cuts. If you get a cut while in the water, immediately wash it with soap and freshwater. If it shows any signs of infection (redness, pain or swelling) or if the cuts are deep: get medical treatment as soon as you can; 2. Eat only fully cooked shellfish, especially if you are susceptible to liver problems or have a chronic health condition like diabetes or a weakened immune system. If you really like raw oysters and are willing to take the chance, you should be absolutely sure the shellfish were not caught in infested water.

For more information, contact the Texas Department of Health: Seafood Safety Division; recent news release ; or Infectious Disease Epidemiologist; Linda Gaul (512) 458-7676. Mail should be addressed to Texas Department of Health, Bureau of Food and Drug Safety, 1100 West 49th Street, Austin, Texas 78756.

HARMFUL ALGAL BLOOM (HAB): Algae are microscopic water plants that can be a nuisance in fresh or salt water and in the case of HAB’s can actually produce toxins that harm other plants and animals. The most familiar HAB along the coast is Gymnodinium breve,called red tide because of the red coloration in the water during the algal bloom. These brevetoxins likely kill fish by paralyzing their gills during contact and causing them to “drown” in the toxic water. If those dead fish are eaten, severe gastric upsets occur. If the fish caught alive don’t appear to be affected by the red tide, they are probably okay to eat. However, the algae’s cellular toxins can also be blown into the air from the water near the surf, so some people just walking along the beach during a red tide incident can have burning eyes or respiratory problems. Probably most dangerous for humans is neurotoxic shellfish poisoning (NSP) from oysters, clams or mussels. These shellfish aren’t hurt by the toxins themselves, but concentrate toxins in their tissue as they feed. Therefore, if people consume shellfish harvested from areas that have had intense red tide infestations, there is a good chance that they will experience gastrointestinal and neurological problems from NSP within a few hours. And these toxins are heat-stable so cooking doesn’t make the shellfish safe.

There are generally a couple of things to remember: 1. Red tide toxins in the air can cause respiratory problems that will subside once people are away from the beach. 2. Finfish are often made ill or killed by red tide and if found dead should not be consumed. Finfish that are caught aline in the area and appear normal should be thoroughly cooked before eating. 3. Red tide toxins accumulate in shellfish and can cause severe gastrointestinal and neurological problems if eaten (raw or cooked) -- even if the shellfish don’t seem ill. Illness from NSP can be very serious and may require medical treatment.

For more information contact Texas Department of Health, Harmful Algal Blooms , 1-800-685-0361 for a 24-hour recording of shellfish harvest area status from TDH, For TPW Recorded Information: (800) 792-1112, To Report Fish Kills: (512) 912-7055

FISH CONSUMPTION BANS AND ADVISORIES: Fish have the healthiest protein people can eat. However, some fish taken from some areas are contaminated with chemicals that can cause health problems. For example, the trace amounts of mercury found in most fish and shellfish aren’t considered dangerous. However, in some fish species the accumulated amount of mercury in tissues of large fish has become too high to be considered safe. Those are fish at the top of the food chain like shark, swordfish, king mackerel (greater than 37 inches), or tilefish and should be eaten rarely or not at all (young children or pregnant women) because mercury has been stored in their flesh. Other fish like salmon, shrimp or catfish usually have very low levels. Lately, federal guidelines have become very explicit about which species are safest or most damaging and can help determine what kind of fish to eat and how often. For more information, see Food and Drug Administration or Texas Department of Health

Other heavy metals (like selenium) or pesticides (PCB’s, Dioxin, DDT, etc.) also affect the healthiness of fish flesh and affect the amount that should be consumed. The TDH, the Environmental Protection Agency, and TPWD all have listings of the waterbodies that have been tested and have received either a fish consumption advisory (eat only specified amounts of certain species of fish) or ban (don’t eat any amount of specified fish). See the following for listings, maps, or printable documents with this information. or . There are also list of the waterbodies tested that have not had advisories or bans applied.

KILLS AND SPILLS TEAM (KAST): The key to a successful investigation of environmental damage caused to fish or wildlife by chemical or pollution spills is a quick response. TPWD has a KAST that is prepared to evaluate fish (or wildlife) kills very quickly but they rely on anglers and others to report the problems. There is a 24-hour communication center (512) 389-4848 for those calls or any local game warden or biologist can be contacted.

Once contacted, the team goes to the area of the pollution incident and tries to stop and remediate the environmental damage. Once the evaluation of the damage is completed, KAST works to get compensation for the damage and repair and restore the area. These individuals are dedicated to maintain or restoring the highest quality habitat for Texas waters.

Reports and general information can be found at on this site. Just remember, their success is only as good as the eyes and ears of outdoors enthusiasts like you.


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