| Electrofishing works well in monitoring state's fisheries |
 LITTLE
ROCK - Fisheries biologists use many techniques to collect bass for
management and research, but few are as effective as electrofishing.
Even fewer are non-lethal to the sampled fish.According to Colton Dennis, the Arkansas Game and Fish Commission's black bass biologist, electrofishing is exactly what it sounds like - using electricity to catch fish. "We use a generator to produce electricity, a variable voltage pulsator to regulate voltage, pulse and frequency and electrodes to transfer the electric current to the water," explained Dennis. "When power is applied, an electrical field is produced around the boat that disables the swimming muscles of fish and temporarily immobilizes them." This method of sampling is especially productive in the spring, when water temperatures begin to rise. As the temperature approaches 60 degrees, black bass begin migrating to shallow water, searching for suitable spawning sites. Once they are concentrated in the shallows, bass are easily captured and biologists can get an accurate estimate of the lake's population. "As the biologist maneuvers the boat along the shoreline, bass located in the electrical field are stunned and are quickly netted and placed in an aerated holding tank," Dennis explained. The fish are then measured, weighed and released unharmed. Unlike some other forms of aquatic sampling, the fish being measured are alive and swimming when the sampling boat leaves the water. "Many anglers have wondered if the fish are injured or killed using this sampling method," said Dennis. "All of our fisheries biologists have gone through extensive certification courses to ensure just enough electricity is used to capture fish without permanent injury." Only a small section of the lake or stream needs to be sampled when using this technique. Using random samples that represent a very small portion of the lake, biologists use statistics to determine the size structure and abundance of bass for the entire body of water. Fish collected with electrofishing gear can be used for tagging studies, for determining the health of a fish population, age and growth rates, and for hatchery brood stock; but the technique is extremely effective in providing data for minimum-length and slot-limit regulations. Dennis noted, "Electrofishing is an effective tool when evaluating a minimum length limit or protective slot limit on a lake. All of our bass regulations are based on data collected by this sampling technique." |
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