Agency raising larger bass fingerlings

Fisheries biologists with Arkansas Game and Fish Commission are always interested in how stocking programs are working in Arkansas’ waterways.

One way Game and Fish hatcheries are improving both largemouth and Florida bass production is by rearing advanced fingerlings to stock in area lakes. In the past, hatchery staff have reared bass to fingerling size, about 1½ to 2 inches, and released them in lakes in the Game and Fish stocking program.

Hatchery staff have been researching and evaluating different techniques to rear bass to 4 inches for a pilot study. When these advanced fingerlings reach about 4 inches, they are branded with liquid nitrogen to create an identifiable mark and then taken to study lakes as part of an ongoing research project with the Game and Fish black bass program.

“When a bass reaches approximately 2 inches in length, its diet shifts from eating insects to feeding on fish and that often means dining on their smaller cohort,” said Dennis Fendley, hatchery biologist at Andrew Hulsey Fish Hatchery. “In a production setting, this increased cannibalism leads to a reduction in numbers of fish available for stocking. This is the same trend seen with walleye, stripers and other predatory fish.”

Hatchery staff at multiple Game and Fish fish culture facilities are evaluating how different feeding regimes and food sources affect the growth rate of bass fingerlings. Biologists hope to increase the survival rate of stocked fish against bigger bass and other predators within the system. A larger fish, in theory, has a better chance of survival.

“When you stock bass fingerlings that are 1-2 inches long, a 15 percent survival rate is considered a success,” said Colton Dennis, Game and Fish black bass program coordinator. “One question we are trying to answer is, ‘can a better survival rate be obtained by stocking fewer but larger bass?’ The biologists also have to determine if the value of the stocking contribution outweighs the cost of rearing a larger fingerling.”

Fendley said it’s not just a matter of food.

“It costs more to feed advanced fingerlings, and it takes more pond space that could be used for more production of smaller fingerlings, so there is a trade-off,” he said.

Jeff Buckingham, a Game and Fish black bass biologist, has designed a pilot study for the program to evaluate the stocking contribution of the stocked branded fish in selected study lakes.

“During sampling if we collect and release 100 bass from a study lake and 10 have a brand then that’s a 10 percent survival rate. If it’s 20 fish that’s even better,” Buckingham said.