Evaluating the consequences of catch-and-release recreational angling on golden dorado (Salminus brasiliensis) in Salta, Argentina

Golden dorado (Salminus brasiliensis) is increasing in popularity as a target of recreational anglers practicing catch-and-release (C&R) in northern Argentina and bordering countries, however science-based best practices have yet to be developed for this iconic freshwater gamefish. We assessed the consequences of C&R on golden dorado captured by anglers on the Juramento River, in Salta, Argentina. Physical injury, physiological stress responses (blood glucose, lactate, pH), reflex impairment, and movement response post-release were compared among handling treatments for golden dorado. The 0min and 2min air exposure groups had significantly higher blood glucose and blood lactate concentrations relative to fish in the baseline group, while blood pH indicated evidence of acidosis in the 2min air exposure treatment relative to baseline values. Golden dorado in the 2min air exposure group also had significantly greater reflex impairment compared to fish without air exposure. An additional 24 golden dorado were affixed with radio tags to examine short-term (20min) post-release behavior with air-exposure treatments of 0min (n=11) and 2min (n=9), as well as fish that were transported downstream in submerged recovery bags (n=4). Subsequent relocations of tagged golden dorado were conducted every 1–2days up to 8 weeks after capture. Upon immediate release, fish often exhibited fallback (−43±49m, n=20), although post-release movement was not significantly different among treatment groups. Fallback distance was correlated with total reflex impairment scores. The translocated fish released downstream exhibited greater upstream movement immediately following release, with three fish returning to the location of capture within 4–12days. No immediate mortality was observed for golden dorado in the physiology assessment, and limited evidence of short-term mortality was present for tracked fish (22 of 24 tagged fish movement detected>2days post-tagging, ≤8% mortality). Our results indicate that minimizing air exposure should be advocated as part of guidelines for C&R for golden dorado. Our study also revealed that impairment of the equilibrium reflex is useful for anglers as an indicator for golden dorado vitality and potential need for monitoring recovery prior to release.