Relative Abundance and Feeding Habits of Bowfin, Spotted Gar, and Largemouth Bass at the Emiquon Preserve and Reelfoot Lake: Can Native Fish Species Control Invasive Common Carp?

In 2011, we sampled Reelfoot Lake to better understand why this aquatic ecosystem has not become dominated by invasive common carp Cyprinus carpio. Reelfoot Lake is similar to the Emiquon Preserve in that they are both shallow, disconnected floodplain lakes which contain bowfin Amia calva, spotted gar Lepisosteus oculatus, largemouth bass Micropterus salmoides, and common carp. However, these lakes differ in that Reelfoot Lake is over 100 years old, while the Emiquon Preserve is only 5 years old. We used standardized pulsed-DC electrofishing at random and fixed sites to assess the fish communities and the diet contents of bowfin, spotted gar, and largemouth bass in both lakes. Our catch-per-unit effort data suggests that largemouth bass relative abundance at Reelfoot Lake was 23.6 fish/hr, but was 26.5 fish/hr at the Emiquon Preserve. Bowfin (6.7 fish/hr) and spotted gar (6.9 fish/hr) relative abundances at Reelfoot Lake were higher than bowfin (0.5 fish/hr) and spotted gar (0.3 fish/hr) relative abundances at the Emiquon Preserve. The relative abundance of the invasive common carp (6.8 fish/hr) was approximate to those of bowfin and spotted gar at Reelfoot Lake, whereas the relative abundance of common carp (2.4 fish/hr) was greater than those of bowfin and spotted gar at the Emiquon Preserve and is increasingly rapidly. Our bowfin, spotted gar, and largemouth bass diet analyses suggest they may not be selecting for young-of year common carp as a prey type. So these species might not be directly influencing common carp via predation but perhaps indirectly through other paths.