Discard Mortality of Black Crappie in Florida

Discard mortality is an important parameter used in population modeling and fisheries management. If released fish experience high mortality, then the benefits of enforcing a minimum length limit will be diminished. Few studies have investigated crappie discard mortality, and these studies focused on White Crappie Pomoxis annularis, which do not exist in Florida. We designed a two-part study to obtain a statistically robust estimate of discard mortality of Black Crappie P. nigromaculatus. Part one of the study was a containment-style pond study where Black Crappie were angled out of 0.24-ha ponds and released into adjacent 0.08-ha ponds, where we observed their mortality for 14 days. We had four replicates (N = 4) and 396 total individuals. Only two crappie died during the experiments, and mean mortality for ponds at 14 days post-release was 0.5% ±0.3 SE. In part two of this study, we sought to determine the relative vulnerability to predation of discarded crappie compared to a control group. We did this by exposing both treatment and control groups to predators (Florida Bass Micropterus floridanus) in an indoor tank setting. Results from part two of the study are forthcoming and will be discussed during the presentation.