Fish diversity in an isolated artificial wetland

Adult, juvenile and larval fishes were sampled in a managed isolated wetland in the Red Chute Bayou floodplain, LA from December 1994 to July 1995. Nineteen species were captured. Principal components analysis of adult fishes showed little difference between sites, but a gradient of habitats and seasons reflecting variable richness was observed. Bowfin (Amia calva), black bullhead (Ameiurus melas), spotted gar (Lepisosteus oculatus), bluegill (Lepomis macrochirus), warmouth (Lepomis gulosus), black crappie (Pomoxis nigromaculatus) and fliers (Centrarchus macropterus) were the dominant adult fishes. Juvenile and post-larval fishes had low catch-per-unit-effort and were dominated by fliers. Principal components analysis distinguished three habitat groups and significant seasonal variation in the juvenile/post-larval fish community. The ichthyofauna resembled that described for irregularly inundated isolated floodplain ponds of the lower Mississippi River valley. The relatively low diversity of this system is probably due to the isolation of the backwaters from active river cycles. The problem may be further compounded by the timing of water drawdown in late spring.