Littoral Habitat Use by Fishes in Lake Conroe, Texas

P. F. Trial, F. P. Gelwick, and J. Cotner, Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas 77843-2258

M. A. Webb, Texas Parks and Wildlife Department, 1004 East 26th Street, Bryan, Texas 77803

The 1981 stocking of grass carp Ctenopharyngodon idella into Lake Conroe, Texas, resulted in dramatic changes to the reservoir’s littoral zone. Prior to 1981, as much as 45% of the reservoir’s surface area was covered with aquatic macrophytes. Today, less than 5% of the shoreline contains aquatic macrophytes. In addition, due to extensive home development, approximately 60% of the shoreline has been converted to structurally simple bulkhead. The remaining 35% of Lake Conroe’s littoral zone habitat consist of complex riprap (7%) and undeveloped, unvegetated, sandy shoreline (28%). As structurally complex littoral zone habitat provides important foraging sites, protection from predation, and nursery areas for many species of fish, it is important to understand how the dramatic changes in the shoreline habitat may be affecting the littoral fish communities within the lake. For 1 year, each of the four different littoral habitat types were sampled seasonally to determine the number of species/m², individuals within a species/m² and biomass/m² of habitat sampled. Four permanent sites were chosen in each habitat type. Sites were surrounded with a large (91.5 m) blocknet. The inside area of the blocknet was measured and electrofished exhaustively. Data from three seasons indicate that riprap and vegetated areas support the highest biomass of fish as well as the highest numbers of species per area sampled. This information will be useful in planning habitat-restoration projects in reservoirs, or when designing or refining mitigation requirements in reservoirs where desirable fish habitat is being removed or degraded by human activities.

Copyright © 1999
Texas Chapter of the American Fisheries Society
Last modified: 01/07/09 06:45:17 AM