Evaluating the Limitations and Applications of the Reflex Action Mortality Predictor Approach for Quantifying Bycatch Mortality

All animals that interact with fishing gear are not necessarily captured, and all that are captured are not necessarily retained. Fishing practices and gear configuration, management regulations, and markets dictate what component of the catch is captured and discarded. The true impact of a fishery and the efficacy of management regulations depend on the mortality rate of these incidentally captured animals. To evaluate this component of fishing mortality, survival rates must be quantified. The need to accomplish this with a simple, non-invasive, inexpensive, and accurate approach was met with the creation of the Reflex Action Mortality Predictor (RAMP). RAMP relates reflex impairment to probability of mortality attributed to a specified stressor. This paper presents results from recent studies using RAMP to assess bycatch mortality of three crab species. This research allowed for an assessment of the efficacy and limitations of RAMP, evaluating: (1) the ability of an established RAMP to accurately predict mortality attributed to novel stressors; (2) captive holding strategies for determining mortality; (3) the effect on reflex impairment of air exposure and time in water; and (4) the utilization of RAMP to evaluate management regulations. Highlighted are warnings and recommendations regarding the utilization of the RAMP approach.