Evaluating the Adequacy of Fish-Habitat Data for the Blue Catfish

Habitat is critical for fisheries management, yet quantitative data on many fish-habitat associations are limited. Here, we assess what habitat data are available for blue catfish (Ictalurus furcatus), an important and popular sport fish. Then, we test if the most commonly cited habitat variables are related to the distribution of acoustically-tagged blue catfish (n = 75, length = 300-1090 mm TL), detected at 57 tracking locations in Milford Reservoir, KS, during 2013. Of 12 peer-reviewed publications on blue catfish habitat from 1961-2011, only 3 (25%) provided quantitative data on some aspect of habitat (25% depth, 8% flow velocity, etc.). The conventional, often repeated, wisdom was that blue catfish occurred in deep areas with faster flowing water. In the field, we did not find quantitative evidence of strong associations between increasing depth and current velocity. Instead, we found the highest abundance of tagged blue catfish at tracking locations in the middle of the reservoir, associated with intermediate values of depth (mean = 9.0 m; SD = 2.1) and moderate current velocities (mean = 0.10 m/s; SD = 0.02). For blue catfish and other fish species, a critical evaluation of conventional wisdom on fish habitat is needed followed by quantitative, across-system studies.