How does catch-and-release angling impact on the post release health of mahseer?
The conservation benefit of catch-and-release (C&R) angling relies implicitly on the assumption that released fish not only survive, but their behaviour and reproductive capacity are also uncompromised by the experience. Joining forces with colleagues from Canada, USA and India, the MT team has just published the following paper in ‘Fisheries Management and Ecology’, which has shown the impacts of C&R on the Cauvery’s blue-fin mahseer to be minimal. Immediately after the field data collection, the preliminary observations of the study were discussed by stakeholders attending the Bannerghatta workshop, which facilitated the development of best practice angling and fish handling protocols.
Shannon D. Bower, Andy J. Danylchuk, Rajeev Raghavan, Sascha E. Clark-Danylchuk, Adrian C. Pinder, Steven J. Cooke (2016) Rapid assessment of the physiological impacts caused by catch-and-release angling on blue-finned mahseer (Tor sp.) of the Cauvery River, India. Fisheries Management and Ecology, DOI: 10.1111/fme.12135
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.
The full article is available on request (FOC) by emailing Shannon Bower firstname.lastname@example.org