Good Fish, Bad Fish
Some Asian carp pose big problems in Texas waters.
By Dyanne Fry Cortez
Several species of exotic Asian carp can be found in Texas waters. Some pose serious threats to our fisheries. If you’re a conscientious angler, it’s good to know the bad guys from the not-so-bad. Here’s a brief introduction to the tribe.
Common carp (Cyprinus carpio) is so common, many anglers may not be aware that it wasn’t always here. Considered “naturalized” in Texas, it’s a popular food fish in some countries. Colorful varieties called koi may be seen in zoo ponds and botanical gardens.
Grass carp (Ctenopharyngodon idella) is a plant eater, often stocked to control unwanted aquatic vegetation. That’s good up to a point, but too many grass carp in the wrong place could potentially alter the food web that supports our native fisheries. For that reason, a permit from the Texas Parks and Wildlife Department is required to stock this fish. Only sterile, nonreproducing grass carp are allowed.
Common carp.
Grass carp.
Silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) may be less familiar to Texas anglers. The Texas Parks and Wildlife Department is taking steps to keep it that way, because they pose big problems. These two Asian carps were imported in the 1970s to control algae in fish-farm ponds. They escaped to the Mississippi River basin, multiplied and thrived. They feast on microscopic plants and animals, which puts them in direct competition with juvenile game fish and important prey species like gizzard shad. When startled by passing boats, silver carp have a tendency to leap out of the water. You may have seen online videos of these fish landing in boaters’ laps.
Silver carp.
Bighead carp.
In Texas, silver carp have been found mostly in the northeast corner near the Arkansas and Oklahoma state lines. Adults grow to 4 feet long and weigh more than 60 pounds — but when they’re little, these silver and bighead carp look a lot like young gizzard shad.
In 2012, to prevent the accidental spread of invasive carp in bait buckets, TPWD imposed a ban on transporting live bait fish from the Sulphur River and Big Cypress Bayou as well as the Red River downstream of Lake Texoma.
TPWD is working with Texas Tech University to pinpoint the range of silver and bighead carp in Texas. Depending on the results, it may be possible to fine-tune those regulations to prevent a full-scale invasion. For updates on what Texas is doing to manage aquatic invaders, visit tpwd.texas.gov/landwater/water/aquatic-invasives.
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