Seasonal Hooking Mortality of Flathead Catfish and Blue Catfish

This study was conducted to estimate the summer and winter hooking mortality of flathead catfish (pylodictis olivaris) caught on trotlines in the Colorado River and Kerrville Reservoir, Texas, and blue catfish (Ictalurus furcatus) caught on trotlines in Livingston Reservoir, Texas. Water temperatures averaged 12.2 and 13.3 C, respectively, during February and March flathead catfish winter experiments, and 27 C during summer experiments. Water temperatures averaged 12.5 and 24 C, respectively, during winter and summer blue catfish experiments. Flathead catfish (range = 352-675 mm total length (TL)) were caught with sizes 7/0 and 8/0 single hooks baited with live green sunfish (Lepomis cyanellus), bluegill (L. macrochirus), and goldfish (Carassius auratus). Blue catfish (range = 165-655 mmTL) were caught with sizes 4/0 to 6/0 single hooks baited with pieces of shad (Dorosoma spp.) and goldfish. Fish were held for 72 hours in 0.61 X 0.76 X 0.91-m metal cages to observe delayed mortality. One of 17 flathead catfish (5.9%; 95% one-tail, upper confidence limit (UCL) = 15.2%) died in the winter and 5 of 35 (14.3%; UCL = 24.0%) died in the summer. Four of 43 blue catfish (9.3%, UCL = 16.6%) died in the summer and none of 35 died in the winter. Overall hooking mortality was 11.5% (UCL = 18.8%) and 5.1% (UCL = 9.2%) for flathead and blue catfish, respectively. There were no significant differences in hooking mortality between seasons for either species (P > 0.05).

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