Abstract

Bass fishing is an extremely popular activity. Following rapid decompression during ascent, fish captured at low depth can develop overinflation of the swim bladder. Swim bladder deflation by transcutaneous fine-needle puncture (known as fizzing) is often advocated as a method to increase post-release survival rates. The objective of this study was to determine if fizzing could impact the health and survival of wild-caught bass (Micropterus spp.). Twenty bass (18 smallmouth - M. dolomieu, and 2 largemouth - M. salmoides) were captured by anglers and allocated into three groups: shallow < 6 m capture (n = 4); deep > 10 m capture with fizzing at day 0 (n = 9); deep > 10 m capture without fizzing (n = 7). Fish were housed for 48h in a 10-m deep net-cage and then euthanized and examined. Potentially life-threatening swim bladder lesions were observed in 56% of fish from the > 10 m - fizzing group, compared to 14% of fish from the > 10 m - no fizzing group. No lesions were detected in the < 6 m - no fizzing group. The lesions included tearing of the swim bladder, observed in five (56%) and one fish (14%) from the > 10 m - fizzing group and the > 10 m - no fizzing group, respectively, and bacterial cystitis, diagnosed in four fish (44%) of the > 10 m - fizzing group. These lesions resulted most likely from fizzing and, to a lesser extent, from barotrauma. This small-scale study suggests that fizzing, as commonly performed by anglers, could have a deleterious impact on post-release survival of bass.

* Presenting author