An ecological context for evaluating the factors influencing muskellunge stocking success

From an ecological perspective, predation, competition or resource partitioning, and abiotic factors interact to affect species distribution and abundance. To make management recommendations, I review research dealing with the relative influence of these factors in determining stocking success of muskellunge Esox masquinongy. Survival of stocked muskellunge is affected by losses to resident predators. Prey preference and composition are also important, and better muskellunge survival and growth occurs in systems with soft-rayed or fusiform prey rather than in centrarchid-dominated systems. However, potential for competition with resident fishes has not been carefully considered. Abiotic factors, particularly temperature, can influence stocking mortality and subsequent growth. Survival increases with size and is maximized with large muskellunge fingerlings (>240 mm), but cost-effectiveness can vary substantially with predator and prey populations. Hatchery rearing techniques can also affect muskellunge stocking success. Pellet-reared fish have lower survival than minnow-reared fish because predation mortality is higher, but both groups exhibit similar food consumption and growth. The parental population can affect survival and growth because temperature-related differences in bioenergetic variables occur among muskellunge populations. In addition to compromising genetic integrity, the mixing of populations with different physiological characteristics may have negative consequences for native populations. Thermal regimes of recipient waters should be considered in choosing the most appropriate population for stocking outside the native range. Muskellunge stocking should be pursued within an ecological context that integrates the relative importance of predation, competition, and abiotic factors. This framework provides a guide for making management decisions concerning populations, hatchery rearing techniques, sizes, and timing of muskellunge introductions into systems with specific characteristics.