By: Carl Vignali, Texas Parks and Wildlife
The sampling of public water bodies is one of the tasks performed by Texas Parks and Wildlife Department’s Inland Fisheries Management crews. There are multiple tools that are used to sample our waters. We use gill nets, hoop nets, trap nets, seines and Electrofishing, depending on which fish populations we are targeting. While each technique will catch a variety of species, they all are designed for particular segments of a waters population. Gill nets are used to target blue catfish, channel catfish, flathead catfish, striped bass, white bass, hybrid striped bass, red drum, and walleye. Hoop nets target the catfish species and trap nets are used to collect crappie. Electrofishing primarily targets bass, sunfish and forage species. For a quick snapshot of the fish that are present in a waterbody we will use electrofishing. The electrofishing (EF) boat consists of an aluminum hull boat with a generator, an electronic pulsator which allows us to control the voltage and frequency of the electricity, and two electrodes which are extended from booms in front of the boat and set into the water. It is basically what old-timers called “phone fishing “using a hand crank telephone. An electric field is produced which travels in the water from the electrodes on the booms back to the hull of the boat. Fish in or near the field will be affected and swim to the top of the water where they are netted out. The fish are only stunned by the electricity enough to allow capture. Once the fish are measured and weighed they are released back into the waterbody. The people netting the fish wear rubber linesmen gloves and rubber boots to insulate them from any electricity.
We were contacted by the staff of Brazos Bend State Park because they were curious about the fish populations of the lakes after the flooding as a result of Hurricane Harvey. The park was closed to the public on the day we went due to high water in the Brazos River so it was a good opportunity for us to sample. We decided to electrofish two lakes: 40 Acre Lake and Elm Lake. Each lake was sampled at twelve sites for five minutes with all fish being collected. The usual species found it Texas waters were present such as largemouth bass, catfish, crappie, sunfish (mostly Redear and Bluegill) and spotted gar. There was also a very healthy population of Bowfin a.k.a. mudfish, mud pike, dogfish, griddle, grinnel, swamp trout and choupique. The male Bowfin had their breeding colors with vibrant green fins and a green hue to the body. We also found Banded Pygmy Sunfish, Pirate Perch and Golden Topminnow all of which are not typically found in our usual sampling locations. All the fish were fat and healthy, indicating the lakes contain plenty of forage. The only invasive or non-native species sampled was tilapia, which are found throughout the region and are not a surprise to find.
Brazos Bend SP is well worth the drive to get there. For fishing, and apparently excellent Bowfin fishing, there are four lakes: 40 Acre Lake, Elm Lake, Hale Lake and New Horseshoe Lake. 40 Acre Lake and Hale Lake both have handicapped accessible fishing piers and Elm Lake has seven small piers along its south side. In addition to fishing, the birding was excellent and in the short time we were there we saw grebes, teal, coots, moorhens, ibis, rosette spoonbills, vermilion flycatchers, woodpeckers, and heard an owl.
Until next time, may your lines stay tight.