Emerging Issues in Catch-and-Release Angling

For years, recreational anglers have been releasing fish alive following capture by rod and reel. Catch-and-release of fish has been considered to be a logical means of sustaining recreational fisheries. However, there is a growing body of literature that details the negative effects of catch-and-release angling. Furthermore, in some jurisdictions beyond America, laws have been enacted that prohibit the release of fish after capture due to animal welfare concerns. Research scientists in the Center for Aquatic Ecology have been engaged in extensive research directed towards understanding the sublethal consequences of catch-and-release angling. Beyond characterizing the negative consequences of catch-and-release, we focus on how to minimize the sublethal disturbances to fish and maximize survival. Below we describe a series of completed and ongoing studies that highlight the range of issues that we are assessing and disseminate some preliminary results.

There is a large body of research examining the injury and mortality resulting from different terminal tackle; however, recent development of new terminal tackle provides opportunities to assess their conservation benefits. A recent example is a study we conducted on the effects of circle hooks on hooking injury and mortality of largemouth bass. Circle hooks differ from conventional "J" style hooks in that the point of the hook is perpendicular to the shank. In marine fisheries, circle hooks have reduced mortality and injury. However, our freshwater research on largemouth bass suggests that circle hooks provide limited conservation benefits compared to "J"-hooks. A confounding variable is that circle hooks catch about half as many fish as conventional "J" shaped hooks.

Sublethal physiological disturbances associated with catch-and-release angling can be quantified and used to evaluate the effects of different angling practices and scenarios (e.g., water temperature, degree of exhaustion). In one study, we monitored cardiac activity of largemouth bass exposed to angling across a range of temperatures. The magnitude of the disturbance was strongly influenced by water temperature. As water temperature increased, fish took longer to recover from the disturbance. We also have assessed the effects of livewell confinement on largemouth bass and determined that fish activity in the livewell increases during wave conditions and that even short-duration air exposure can drastically delay recovery. Recently we have collaborated with a team of scientists at Queen's University in Ontario to link our research using cardiac monitors with more conventional blood and muscle biochemistry.

Feeding is an essential activity for fish. Evidence suggests that surprisingly small interruptions in food consumption may have negative consequences for growth. We examined the effects of simulated angling tournaments on largemouth bass feeding rates. Control fish consumed half of the prey introduced into their tank within the first minute, whereas those fish exposed to either 21 or 26deg.C consumed half of the prey at 8 and 25 hours respectively. Using these empirical data, we can run bioenergetics simulations to estimate the long-term (month, year, lifetime) consequences of tournament stressors on growth of fish.

Perhaps the most challenging aspect of catch-and-release angling to quantify is the fitness implications of such activities. Our labs have been addressing this issue on several fronts. Lakes in Illinois and Ontario are snorkeled extensively during the bass spawning period to monitor the success of parental nest-guarding males exposed to different capture scenarios (Fig. 1). We also use experimental ponds at INHS field sites to conduct controlled fitness manipulations. A recent study conducted by our group determined that exposing male and female fish to a simulated angling tournament prior to spawning resulted in spawning delays, the production of smaller fry, and the production of fewer individuals. We are currently undertaking a follow-up study to examine the mechanisms underlying the negative consequences.

These examples of some of our current research activities outline some of the major issues associated with catch-and-release angling. By providing anglers and fisheries managers with defensible data, we can help to ensure the sustainability of recreational fisheries in Illinois and throughout North America.

Steven J. Cooke, Michael Siepker, Kenneth Ostrand, David Philipp, and David Wahl, Center for Aquatic Ecology

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