Venting, often called fizzing, is puncture of the swim bladder with a needle to expel gases. Two of the most common methods of barotrauma symptom relief are swim bladder venting and deep-water release. Relieving major symptoms before release, or releasing with aid, is the prevailing strategy for releasing fish affected by barotrauma.
#BAROTRAUMA FISH HOW TO#
Regardless of the circumstances, anglers and CFE staff often require specific instructions on how to handle fish with barotrauma (e.g., harvest, release unaided, or release with aid). 2009), or because of weight penalties for nonreleasable fish. In addition, anglers in competitive fishing events (CFEs) may release fish with barotrauma during culling ( Nguyen et al. Fish with barotrauma are often unsuitable for release without intervention however, whether they are released or harvested depends on regulations combined with angler discretion. 1996 Gravel and Cooke 2008 Schreer et al. The positive buoyancy and loss of equilibrium associated with barotrauma are immediate issues for CAR because fish are unable to submerge consequently, they are vulnerable to delayed mortality from exposure, stress, and predation ( Bruesewitz et al. 2009) to catastrophic decompression wherein the swim bladder ruptures ( Rummer and Bennett 2005). The severity of injuries ranges from mild decompression (e.g., Nguyen et al. The rapid pressure reduction that occurs when a fish is angled in deep water and brought to the surface can result in a suite of physiological impacts, including swim bladder overexpansion, organ eversion, hemorrhaging, and eye bulging ( Bartholomew and Bohnsack 2005 Pribyl et al. If deep-water angling cannot be avoided, we recommend noninvasive descending over venting.īarotrauma is a widespread issue for recreational catch-and-release (CAR) fisheries. Eliminating catch-and-release angling in deep water is the best means of managing barotrauma in Walleye. The consequences of these short-term changes to Walleye behavior from a fisheries management perspective are unclear. Fin weighting is not an effective catch-and-release aid for Walleye with moderate-to-severe barotrauma, and swim bladder venting may alter short-term, postrelease movements and habitat use. Our data suggest that without treatment, mortality of Walleye with barotrauma could be as high as 50%. Telemetry did not indicate mortality of any fish in the in situ study. Descended fish also used significantly deeper depths than vented fish, and control fish were intermediate in the depth used. Control and descended fish used larger areas and volumes of the lake than vented fish. However, there were no statistically significant differences in distance metrics among groups. In a concurrent in situ study, acoustic telemetry showed that Walleye without barotrauma (controls) made variable postrelease movements (total distance: 5.1–27.6 km), descended fish behaved similarly to controls (4.7–28.6 km), and vented fish made the shortest movements (2.6–16.7 km). All vented fish were negatively buoyant, but 73% were releasable after the holding period. Fin weighting immediately improved condition by enabling fish to regain correct orientation however, only 53% of fin-weighted fish recovered sufficiently to be released. In a short-term ex situ experiment, 50% of untreated fish with barotrauma did not recover sufficiently to be released after 20 h. Here, we assess the condition and behavior of tournament-caught Walleye Sander vitreus with barotrauma by using three popular relief methods: 1) swim bladder venting, 2) deep-water release (descending), and 3) livewell reorientation with fin weights. Relief of barotrauma symptoms is necessary to reduce mortality, but we currently know little about sublethal effects associated with relief methods. Barotrauma causes stress and impairment in fish and can cause mortality after catch and release.