Estimating the survival probability of animals released from fisheries can improve the overall understanding of animal biology with implications for fisheries management, conservation and animal welfare. Vitality indicators are simple visual measures of animal condition that change in response to stressors (like fisheries capture) and can be assessed to predict post-release survival. These indicators typically include immediate reflex responses which are typically combined into a score. Vitality indicators are straight-forward and non-invasive metrics that allow users to quantify how close (or far) an animal is from a normal, ‘healthy’ or baseline state, which in turn can be correlated with outcomes such as survival probability, given appropriate calibration. The literature on using vitality indicators to predict post-release survival of animals has grown rapidly over the past decade. We identified 136 papers that used vitality indicators in a fisheries context. These studies were primarily focused on marine and freshwater fishes, with a few examples using herptiles and crustaceans. The types of vitality indicators are diverse and sometimes taxa-specific (e.g. pinching leg of turtles, spraying water at nictitating membrane of sharks) with the most commonly used indicators being those that assess escape response or righting response given the vulnerability of animals when those reflexes are impaired. By presenting Pacific salmon fisheries as a case study, we propose a framework for using vitality indicators to predict survival across taxa and fisheries.

Without sufficient time to diffuse air from their swim bladders, physoclistous fish caught in deep water can exhibit symptoms of barotrauma. In this study, we tested the effectiveness of four barotrauma relief techniques on 76 walleye ( Sander vitreus) and compared their 10 min post-release behaviour and depth selection with an untreated control group using a biologger containing a tri-axial accelerometer and depth sensor. Vented fish showed the best success rate of returning to depth, while no untreated controls were able to swim down. For fish that remained at depth, half were found to have lost orientation and were upside down during the entire monitoring period, with this orientation being strongly associated with the relief method. Vented fish had higher chances (80%) of remaining in the correct orientation at depth compared with the other methods (average of 38%). Our research shows that the best way to prevent negative outcomes of barotrauma is to avoid fishing at depths that yield barotrauma; however, if unavoidable, affected fish should be carefully vented by trained anglers to best reduce post-release impairments.

There is a growing body of research focused on how angled fish respond to catch-and-release (C&R). However, most of those studies do not span a wide range of body sizes for the targeted species. Physical injury and physiological responses to C&R can be size-dependent, and methods used for landing fish of different sizes vary. As such, studying the response to C&R across a range of fish sizes may help inform best practices that improve outcomes for released fish. Northern Pike (Esox lucius) widely ranges in body size. Anglers may land them by hand, cradle, or net, and they are often released voluntarily or to comply with regulations. We angled 25 Northern Pike (total length 620–1030 mm) from one population and recorded fight, handling, and unhooking times across landing methods (i.e., hand, cradle, net). Prior to release, a pop-off biologging package was temporarily affixed to each fish to monitor locomotor activity, depth, and water temperature during a 12-h period post-release to understand how the interaction of landing method and body size influenced post-release behaviour and short-term fate. Fight and handling time increased with increasing body size. Northern Pike landed with a cradle or net had shorter fight times but longer handling times, compared to fish landed by hand. Post-release locomotor activity was greater for larger fish and those landed with a net. Fish 775mm landed by hand had reduced locomotor activity compared to fish landed with a net. There was no post-release mortality observed. Collectively, anglers should use a net for Northern Pike >775 mm to avoid long fight times and reduce post-release exhaustion, but also attempt to reduce the extent of handling associated with fish landed by net.

Debate about the potential benefits and risks of live sonar technology (also known as live imaging sonar and forward-facing sonar) in freshwater recreational fisheries includes growing discussions regarding regulation. Synthesizing sparse literature, experiences of the coauthors, and observations from traditional and social media, we revealed a varied range of potential outcomes for fisheries when this technology is used. Of particular concern is the ability to find fish that were previously cryptic and to target them in ways that increase capture efficiency (e.g., through snagging where legal or more accurately presenting lures or baits); thus, increasing catchability. Conflicting views within the recreational fishing community about the “fair chase” aspect of this technology have prompted discussions regarding regulations. We anticipate continued debate around this topic and hope that this paper will inspire more empirical research (ecological and human dimensions) to provide resource managers and the recreational fishing community with insights and guidance on how to ensure that live sonar is used in ways that benefit fisheries management and stakeholder interests.