Effect of Hook Style, Bait Type, and River Location on Trotline Catches of Flathead and Channel Catfish

Abstract

Trotlines can be used to provide data on catfish populations, but better understanding of trotline selectivity is needed. We compared differences in the presence or absence of channel catfish Ictalurus punctatus and flathead catfish Pylodictis olivaris caught on trotlines among hook types, bait types, substrate types, channel types, water depths, and woody debris complexities in two South Dakota rivers. Channel catfish were 3.5 times more likely to be caught on hooks baited with cut common carp Cyprinus carpio, and flathead catfish were 28 times more likely to be caught on hooks baited with live black bullheads Ameiurus melas. Sea-circle hooks caught fewer catfish of either species than O'Shaughnessy or modified circle hooks. Channel type, water depth, and substrate type affected catches of flathead and channel catfish from the Big Sioux River, but did not influence catches of either species on the James River. The Big Sioux River had greater habitat variability, thereby increasing our chances of finding differences in trotline catches between habitat types. Our research highlights some of the biases associated with using trotlines to collect flathead and channel catfish, but it suggests that trotlines can be used to supplement data on size structure and the total catch of flathead catfish longer than 450 mm and to sample flathead and channel catfish in places where habitat characteristics render other gear types ineffective.