Effects of Structural and Spatiotemporal Factors on Fish Use of Artificial Habitat

We evaluated artificial habitat use in relation to structure size and shape and the spatiotemporal factors of season, diel period, and reservoir region in a Texas reservoir.  Recycled Christmas trees were used to construct three sizes of clustered- and linear-shaped structures; fishes at each were sampled with electrofishing.  Largemouth Bass Micropterus salmoides and Bluegill Lepomis macrochirus comprised 57% of fish collected.  Largemouth Bass exhibited greater percent occupancy of large structures, higher CPUE in small structures, and mean total length (TL) was lower in clustered structures at night.  Bluegill percent occupancy and CPUE were significantly greater in clustered structures; however, larger individuals were more often found in linear structures.  Spatiotemporal differences in percent occupancy, CPUE, and mean TL were apparent with greater abundance of both species during summer and fall and larger mean TL of Largemouth Bass during spring.  Percent occupancy by Largemouth Bass was higher in the lower reservoir; however, mean TL was higher in the upper reservoir.  Percent occupancy by Bluegill, as well as CPUE, was greater in the lower reservoir.  Our results suggest that structure size and shape, as well as the spatiotemporal factors examined, should be considered in habitat enhancement efforts.