Growth of blue, channel and flathead catfish in selected habitats of the lower Mississippi River

Waterway management practices enacted by the U.S. Army Corps of Engineers have created a system of characteristic habitats within the course of the Mississippi River. This study attempted to assess the ecological impact of these habitats upon the age structure and growth rate of blue, channel, and flathead catfish. Ancillary problems included estimation of generalized growth parameters and evaluation of existing methods of estimating growth utilizing pectoral spines.

Catfish were collected from River during five sampling periods. Relative abundance estimates for each sample period and habitat suggest migration of individuals in all species across habitats, possibly in response to environmental fluctuations. Such migrations confound delineation of habitat induced Habitat utilization is apparently uncorrelated growth differences. with individual age.

Significant differences in mean growth increments were detected between certain age classes. There was no apparent pattern in these differences to indicate environmetal conditions during specific years as being particularly detrimental to growth, Generalized growth for each species is predicted through application of the von Bertalanffy growth model. The relationship between total length and weight was described for each species by the curvilinear function, W = aL^b.

Growth estimates for all species were based on measurements taken in the anterior region of cross-sections made at the distal end recess in pectoral spines. of the basal These measurements provided more reliable estimates than did measurements taken in other areas. Additional growth estimates for flathead catfish were based on measurements from cross-sections of the articulating process. These sections revealed earlier annuli in older fish more consistently than did basal recess cross-sections.