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.

Temperature effects on the physiological status and reflex impairment in European grayling Thymallus thymallus from catch-and release angling

“…Typically, the timing of blood sampling has been either from the end of timed air exposure treatments (e.g. Bower et al, 2016b;Lennox et al, 2016) or immediately following reflex impairment tests (e.g. Bower et al, 2016b;Pinder et al, 2016).…”

“…Bower et al, 2016b;Lennox et al, 2016) or immediately following reflex impairment tests (e.g. Bower et al, 2016b;Pinder et al, 2016). In considering the limitations of available tools and their utility in C&R studies, Cooke et al (2013) concluded there is no optimal protocol for blood sampling in the field and, instead, recommended that studies should focus on the comparison of treatment groups as opposed to placing inappropriate confidence in absolute values.…”

“…In recent years, there has been considerable attention directed towards understanding the stress response and subsequent survival and performance of a broad range of C&R angled marine, freshwater and transitional sport fishes (e.g. bonefish (Albula vulpes) Danylchuk et al, 2007;Atlantic cod (Gadus morhua) Weltersbach and Strehlow, 2013; peackock bass (Chichla ocellaris) Bower et al, 2016a; mahseer (Tor khudree), Bower et al, 2016b; Atlantic salmon (Salmo salar) Lennox et al, 2017). There has been specific emphasis on the effects of angling on disruptions to baseline blood chemistry as a secondary (physiological) stress response (Cooke et al, 2013), and the application of simple reflex action impairment indicators as a tertiary (whole body) stress response (Davis and Ottmar, 2006;Davis, 2007Davis, , 2010.…”

Recommendations for the future of recreational fisheries to prepare the social‐ecological system to cope with change

“…Hühn & Arlinghaus ; Bower et al . ; Olaussen ). Although with a primary objective to reduce mortality, catch‐and‐release can also lead to fitness impacts (Richard et al .…”

“…Accordingly, the utility of catch-and-release angling and its effects on individual fish and populations has received considerable attention in recent years (e.g. H€ uhn & Arlinghaus 2011;Bower et al 2016;Olaussen 2016). Although with a primary objective to reduce mortality, catch-and-release can also lead to fitness impacts (Richard et al 2013) and affect entire populations (Coggins et al 2007;Johnston et al 2015), in turn demanding continued attention by scientists and managers to develop science-based bestpractice guidelines (Arlinghaus et al 2007).…”