Rapid assessment of the physiological impacts caused by catch-and-release angling on blue-finned mahseer (Tor sp.) of the Cauvery River, India.

Abstract

Forty-nine blue-finned mahseer (Tor sp.; mean total length 458 ± 20 mm) were angled using a range of bait/lure types, angling and air exposure times in water that averaged 27 ± 2 °C over the course of the assessment. No cases of mortality were observed, and rates of moderate and major injury were low, with 91% of mahseer hooked in the mouth. More extreme physiological disturbances (i.e. blood lactate, glucose, pH) in mahseer were associated with longer angling times. Sixteen fish (33%) exhibited at least one form of reflex impairment. Moreover, longer air exposures and angling times resulted in significant likelihood of reflex impairment. Findings suggest that blue-finned mahseer are robust to catch-and-release, but that anglers should avoid unnecessarily long fight times and minimise air exposure to decrease the likelihood of sub-lethal effects that could contribute to post-release mortality.