Consequences of simulated multiple catch-and-release events and different handling procedures on reflex impairment, ventilation rate, and body condition in Tor khudree

As catch-and-release becomes more popular and angling pressure increases, it is likely that fish in popular fisheries will experience catch-and-release events on more than one occasion (i.e., “multiple captures”). Anecdotal reports from anglers suggest that blue-finned mahseer ( Tor khudree ) in WASI Lake, Karnataka, India, commonly experience multiple capture events that are closely timed together (e.g., often on successive days). To determine whether multiple capture events were likely to result in cumulative physiological effects compared to single capture events, we quickly angled (i.e., landed in < 2.5 min) 124 blue-finned mahseer and placed them in one of four simulated capture treatment groups: control, air exposure, chase, or a combination of air exposure and chase. Blue-finned mahseer were held overnight in a net pen and subjected to a second (n = 91) or third (n = 60) instance of simulated capture. Our results showed increasing ventilation rates and condition score but no pattern in reflex impairment score in blue-finned mahseer for each treatment group and across each day. Ventilation rates were lowest in the air exposure and combination treatments than for other treatment groups, possibly indicating a masking effect from air exposure. The findings of our study indicate blue-finned mahseer are relatively robust to capture-related stressors, even when experienced with short intervals between fisheries encounters; however, we urge further research for improved understanding of the manner in which these stressors interact, particularly in tropical, freshwater environments.