Search

Growth and ultimate size can provide important population insights and a sound biological basis for setting length limits, which can be the best single regulation for preventing overexploitation of muskellunge (Esox masquinongy) populations. A system was developed, using cleithral age and total length at age confidence limits (CL) data, to determine reproductive and growth potential (ultimate size) for calculating and setting increased size limits based on minimum reproductive size (upper 99% CL at age at first maturity + 2 year) and minimum ultimate size (MUS) calculated from the lower 99% CL—minimum ultimate size limit (MUSL). MUS also provides a trophy standard and an index of relative size for comparing trophy potential of individuals within and among populations. Guidelines are provided for determining minimum sample size (mean ± 95% confidence interval = 12 ± 4) and minimum age (8-10 ± 2.0 year) required to produce valid von Bertalanffy growth trajectories. MUS, MUSL, and trophy standards for both length and estimated weight are provided for female and male muskellunge from 14 Ontario sources. Mean MUS, or trophy standard, for females was 115 ± 10.3 cm (MUSL range 75-135) and 11.1 ± 2.6 kg (2.5-17.5) and for males was 95 ± 7.5 cm (66-110) and 6.1 ± 1.3 kg (1.9-9.2). These indices can precisely define growth and growth potential for muskellunge populations and individuals and can be used to better manage and maintain or improve the quality of muskellunge populations and fisheries. [ABSTRACT FROM AUTHOR]

The muskellunge, Esox masquinongy, fishery in the St Lawrence River is believed to have declined significantly from historical levels and reached critically low levels during the 1970s. Over-exploitation caused by liberal angling regulations, and loss and alteration of critical spawning and nursery habitat probably contributed to this decline. In 1980, a St Lawrence River Muskellunge Management Work Group comprising resource managers and several advisors, including E.J. Crossman, to whom this symposium is dedicated, was created to address research and management needs. A trophy muskellunge management strategy was implemented including more restrictive harvest regulations, public education promoting "catch and release", and protection of spawning and nursery habitats. Age and growth information obtained from cleithra analysis indicated the need for increased size limits to adequately protect spawning stocks. Research efforts have developed a biological information base and monitoring tools to guide management decisions and evaluate responses. Over 100 spawning and nursery locations have been identified in US and Canadian waters leading to improved protection of critical habitats. An angler diary program shows a decline in the number of fish being harvested and a local muskellunge release award program implemented in 1987 has logged over 1000 releases of fish at least 44″ in length. Adult muskellunge monitoring in eleven spawning areas revealed an increase in mean total length of over 63 mm (>2.5 inches) after the regulation changes. Monitoring of age-0 muskellunge by use of seining surveys (1997-2005) indicates consistent reproductive success with the potential for several strong year-classes. Improvements in the muskellunge population and fishery are attributed to the progressive management action and a united community response. [ABSTRACT FROM AUTHOR]