Cooperative Fish and Wildlife Research Units Program: Oklahoma
Education, Research and Technical Assistance for Managing Our Natural Resources

Hoop-nets are rapidly becoming the preferred gear type used to sample channel catfish Ictalurus punctatus in impoundments and many managers have standardized the number of hoop-net series based on impoundment size with a maximum of eight in impoundments greater than 60 ha. However, the utility and precision of this approach in larger (> 200 ha) impoundments has not been tested. To determine how hoop-net number affected the catch of channel catfish in larger impoundments, we sampled six reservoirs greater than 200 ha using 16 tandem hoop-net series and estimated the number of net series required to achieve various levels of precision using Monte Carlo bootstrapping techniques. Catch rates were variable among and within impoundments and using 16 hoop-net series was effective at obtaining a relative standard error (RSE) of 25 in all but one lake; using eight series achieved a similar level of precision in only one impoundment. The required number of net series to achieve RSE of 25 or 15 was positively associated with CV of the sample but was not significantly correlated with reservoir surface area. Channel catfish have long been characterized as a habitat generalist suggesting that variability in catch would be low but our results had high variability by sampling site. Our results suggest that future studies describing habitat relationships for channel catfish in impoundments could improve sampling strategies.