Utility of Regulations for Managing Fish with Contrasting Life Histories and Angler Behavior

Regulations are typically intended to prevent overfishing in fish stocks and improve angler satisfaction through catches of larger numbers and/or sizes of fish.  Given the diversity of recreational fisheries that have developed around the world, there are certainly cases where regulations can be essential for these goals.  However, in other cases regulations can be ineffective and possibly harmful to recreational fisheries, and evaluation of regulation outcomes is essential.  We examined two popular sport fish in the USA and Australia to assess the utility of regulations to manage recreational fisheries.  Largemouth bass Micropterus salmoides fisheries in the USA have undergone large increases in voluntary release of fish by anglers, and length regulations are generally not as effective in restructuring largemouth bass abundance size structure as they were prior to about 1990 .  Fisheries biologists have expressed concern that growth rates have declined owing to low harvest and increased largemouth bass density.  In contrast, voluntary release of fish by anglers has increased for Murray cod Maccullochella peelii fisheries in Australia, but harvest remains an important fishery component among anglers.  Regulations are required to prevent recruitment overfishing in in some Murray cod populations, and there is work underway to re-assess length limits for Murray cod to optimize multiple goals of sustainability and angler satisfaction.  Both largemouth bass and Murray cod fisheries have closed season regulations to protect spawning fish, but the effectiveness of these regulations has received little evaluation.  Thus, the utility of regulations differs substantially between largemouth bass and Murray cod fisheries, owing to differences in angler behavior and attitudes regarding harvest.  Angler education may be the only way to improve the utility of length regulations for largemouth bass by increasing angler harvest.  Experimental evaluations of size limits and closed seasons are needed to understand the merit of these regulations in both fisheries.