Smallmouth bass (Micropterus dolomieu) were collected from a reach of the James River, Virginia undergoing American shad (Alosa sapidissima) restoration and fish passage projects. Diet and growth of these specimens were compared to specimens collected prior (1987-1990) to American shad restoration and fish passage. The Piedmont James River was stocked with >5 million American shad larvae annually since 1995 and was re-opened to migratory fish in 1999. Mean lengths-at-age (ages 1-4) were back-calculated from scales and compared using the Mann-Whitney Test. Smallmouth bass collected in 2002 had a significantly lower mean length-at-age for age 2 specimens compared to 1987-1989 smallmouth bass (P=0.04). Stomach contents were placed into four major categories (fish, crayfish, aquatic insects, terrestrial insects) and compared using Schoener's Diet Overlap Index. Schoener's Index produced a score of 0.94; indicating very high diet overlap. In 2002, Centrachidae was the dominant fish prey family and redbreast sunfish (Lepomis auritus) was the dominant species. American shad was not observed in stomach samples during 1987-1990, but was the second most common fish species prey species identified in 2002. Recovery of American shad from smallmouth bass indicates smallmouth bass are utilizing forage produced by restoration stockings. No semi-migratory fish species using new fish passage structures were recovered fiom smallmouth bass stomachs. Fish prey was measured by weight, number of items, and by occurrence; and placed in six family categories for comparison. Schoener's Index produced scores ranging from 0.26 for prey weight to 0.40 for prey occurrence, indicating low fish prey diet overlap. These data indicate that smallmouth bass are utilizing new forage resulting from restoration activities, but growth rates have not changed significantly. Smallmouth bass may not be forage-limited in the study area.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd_retro-1095 |
| Date | 01 January 2007 |
| Creators | Hopler, David A. |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Retrospective ETD Collection |
| Rights | © The Author |
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