Tournament-associated Mortality in Black Bass

Abstract

I compiled estimates of tournament-associated mortality in black basses (Micropterus spp.) for 130 tournaments held between 1972 and 1996. Initial mortality decreased significantly (P < 0.0001) between the 1970s (19.5%), and the 1980s (6.6%) and 1990s (6.5%). I found no difference in initial mortality (P = 0.9885) between the 1980s and 1990s. Delayed mortality was 10.4% in the 1970s based on limited data. Estimates of delayed and total mortality for the 1980s (20.9% and 26.2%, respectively) and 1990s (23.3% and 28.3%, respectively) were not significantly different (P ≥ 0.7222). Thus, no evidence exists of a decline in initial, delayed, or total mortality since at least the mid-1980s. This suggests that recommendations made by previous researchers for reducing tournament-associated mortality were disregarded or ineffective. Meta-analysis of correlations shows a strong positive relationship between water temperature, and initial (r = 0.51 ± 0.00) and delayed mortality (r = 0.36 ± 0.000). There was a strong negative relationship between tournament size and initial mortality (r = −0.54 ± 0.000), and a moderately strong positive relationship with delayed mortality (r = 0.30 ± 0.000). I also found a moderately strong but nonsignificant positive relationship between fish size and initial mortality (r = 0.31 ± 0.197), and a moderately weak negative relationship with delayed mortality (r = −0.13 ± 0.056). Nonlinear regression of initial, delayed, and total mortality on water temperature for tournaments conducted during 1980–1996 explained 20%–30% of the variation in mortality. Initial mortality appears to be compensatory in its effect on total mortality. Estimates of initial mortality alone provide no information on the magnitude of total tournament-associated mortality; therefore, both initial and delayed mortality must be measured. These results also suggest that a substantial portion of tournament-associated mortality is the result of injuries sustained during hooking, playing, and landing of fish.