Lure-size Restrictions in Recreational Fisheries

Length and possession (creel or bag) limits are among the most commonly used regulations for management of recreational fisheries. Although several types of length limits (e.g., minimum, maximum, protected slot, and inverse slot) are used to manage fisheries, all require that anglers release certain sizes of fish. Daily possession limits also require release of captured fish after anglers’ catches reach prescribed limits. Depending on environmental conditions such as water temperature (Muoneke 1992) and dissolved oxygen concentration (Hickman 1998), angler handling (Cooke et al. 2001), bait type (e.g., live bait versus artificial lures) (Clapp and Clark 1989; Diggles and Ernst 1997), bait orientation (Broadhurst and Hazin 2001), and hook type (Klein 1965; Matlock et al. 1993), a variable proportion of released fish does not survive capture, handling, and release. Mortality rates of released fish often are acceptable but typically are believed to be “high,” warranting management attention, when they exceed 20% (Muoneke and Childress 1994). The success of length limits in attaining their intended purposes depends on the survival of released fish (Muoneke and Childress 1994). Although mortality of angler caught and released fish can be very low (Dunmall et al. 2001; Diggles and Ernst 1997), it may be excessive at certain times of the year or for fish captured under specific circumstances. For example, Wilde et al. (2000) reported that mortality of striped bass (Morone saxatilis) could exceed 30% (artificial lures) to 40% (natural baits) during summer when water temperatures exceed 25•C. Mortality of red snapper (Lutjanus campechanus) increases with depth of capture, with a mortality rate of 44% observed among fish captured at 37 to 40 m (Gitschlag and Renaud 1994). Similarly, mortality of yellow perch (Perca flavescens) (Keniry et al. 1996) and largemouth bass (Micropterus salmoides) (Feathers and Knable 1983) is related to depth of capture, and can exceed 50% among fish captured from depths greater than 15 m (yellow perch) or 27 m (largemouth bass). Anglers targeting these species may catch and release a substantial number of fish, which are subject to a high rate of catch-and-release mortality, before catching their limits of legal-length fish. Under these conditions, catch and release is inconsistent with Armstrong et al.’s (1990) concept of good fisheries management, which requires that fishing gears catch target-length fish while allowing nontarget-length individuals to escape unharmed. Further, high rates of mortality are difficult to defend in light of the ongoing debate about the ethical status of catch-and-release fishing (de Leeuw 1996; Balon 2000; Aas et al. 2002). The size of prey that predatory fishes can capture and consume is directly related to predator length and gape (Werner 1974; Dennerline and Van Den Avyle 2000; Hartman 2000). Because most recreationally important fishes are carnivorous, these relationships between predator length and prey size suggest that, on average, the size of baits or artificial lures used by recreational anglers might be regulated to manipulate length of fish captured (Miranda and Dorr 2000). Catch rates of commercial fishing gears for undersized fish which, must be discarded and which reduce fishing efficiency for larger, more valuable individuals, can be reduced by using larger baits (Løkkeborg 1990; Løkkeborg and Bjordal 1995; Huse and Soldal 2000), hooks (Cortez-Zaragoza et al. 1989; Otway and Craig 1993), and lures (Orsi 1987; Orsi et al. 1993). Further, catch rates of larger fish may be unaffected (e.g., Willis and Millar 2001), or may even increase because of increased gear efficiency (Ralston 1990) and reduced competition between small and large fish (Løkkeborg and Bjordal 1992). In this article we provide an experimental evaluation of the potential use of lure-size restrictions to reduce the catch of undersized fish as a means for indirectly implementing, or reinforcing, a minimum-length limit. We use computer simulations to further explore the relationship between largemouth bass population size structure and lure-size effects on the length of fish caught. Because lure color may affect catch rates (Hsieh et al. 2001) we also present results from an experimental assessment of Lure-size Restrictions in Recreational Fisheries