Presence of food organisms in the prolarval environment as a factor in the growth and mortality of larval muskellunge (Esox masquinongy)

Three different feeding programs were used to assess the need for zooplankton in the environment of prolarval muskellunge. These were: (1) no zooplankton available to the larvae (filtered water) until 80% of them had become free‐swimming, with pond zooplankton introduced daily thereafter, (2) pond zooplankton introduced daily after hatching was 90% complete, and (3) Artemia nauplii (under 4 days old) introduced 3 times daily beginning with 90% hatch.

Neither mortalities nor dry weights differed significantly between treatments, indicating that presence of food organisms prior to swim‐up was not critical to survival or growth of muskellunge larvae under the conditions of this experiment. Artemia appear to be a satisfactory hatchery diet for larval muskellunge during their first 3 weeks of life.

Survival, growth and prey of Esocidae in experimental systems

Survival (July to November) of young‐of‐the‐year esocids stocked in 0.2‐hectare experimental ponds in Missouri was: muskellunge (Esox masquinongy), 24%; northern pike (Esox lucius), 58%; and the F1 hybrid of these two species (commonly called the “tiger muskie”), 74%. Survival of yearlings from April to September was: muskellunge, 80%; northern pike, 90%; and hybrids, 85%. Growth rate of yearlings of all three forms was rapid in late spring, declined to a seasonal low in July, and then increased until the ponds were drained in September. Average weight gain of the hybrids (719 g) during their second year of life in ponds was significantly greater than that of northern pike (617 g) or muskellunge (615 g). Maintenance diets (grams of food per gram of fish) calculated for fish in tanks (1.2 × 4.8 × 1.1 m) for 28‐day periods were as follows: northern pike, 0.23; muskellunge, 0.51; and hybrids, 0.62. Food conversion efficiencies in tanks were: northern pike, 29.0%; muskellunge, 25.0%; and hybrids, 22.0%. Non‐game species were more vulnerable than game fishes to esocid predation in tanks. An esocid can be stocked in addition to or as an alternative to largemouth bass (Micropterus salmoides), walleye (Stizostedion v. vitreum), or striped bass (Morone saxatilis) because of a faster rate of growth. The hybrids may be the most desirable form of the three esocids because of rapid growth rate, intermediate angling vulnerability, and ease of rearing in a hatchery compared to either parent species.

Influence of cisco (Coregonus artedi) on muskellunge (Esox masquinongy) mean length, population size structure and maximum size in northern Wisconsin lakes

Population size structure and maximum size of managed sportfish populations are dictated by abiotic, biotic, ecosystem, and anthropogenic influences. In their native ranges of northern Wisconsin, muskellunge (Esox masquinongy ) and cisco (Coregonus artedi ) are co‐adapted cool‐ and cold‐water species where cisco presence may influence population size structure and maximum size of muskellunge. We tested whether muskellunge size structure indices (length‐frequency distributions, proportional size distribution), mean length, and mean maximum length of muskellunge differed when cisco were present or absent in Ceded Territory of Wisconsin (CTWI) lakes during 2015–2018. Cisco presence had a positive influence on size structure and mean length of individual muskellunge within populations. In contrast, cisco presence had no influence on the mean maximum length of muskellunge observed in CTWI populations suggesting that other factors may be better predictors of this metric than cisco presence. In cisco lakes, mean muskellunge length was negatively correlated with mean cisco length suggesting that gape limitation may be a factor influencing population size structure and individual growth rates. Therefore, cisco populations with primarily large individuals may be unavailable to muskellunge as forage. Our results suggest that cisco are an important forage species for some aspects of muskellunge population ecology; however, other factors may also contribute to muskellunge population size structure and maximum size outcomes. As such, conservation of remaining cisco populations in Wisconsin is critical because they influence muskellunge population ecology in lakes where the species coexist. Future research is needed to better understand the interactions of cisco, abiotic and biotic factors, and anthropogenic influences on muskellunge growth dynamics.

Comparison of food consumption, growth and metabolism among muskellunge: An investigation of population differentiation

We conducted laboratory evaluations of food consumption, growth, and metabolic rate as functions of water temperature (5–27.5°C) to examine how the young of year in six populations of muskellunge Esox masquinongy (Kentucky, Minnesota, New York, Ohio, St. Lawrence River, and Wisconsin) from three drainages might perform under various thermal regimes. Relative food consumption (g·g−1·d−1) and growth (g·g−1·d−1) were similar among populations at lower temperatures (5 and 10°C, but at higher temperatures (15–27.5°C) fish from Wisconsin and Ohio had higher consumption and faster growth rates than fish from Kentucky and the St. Lawrence River. Metabolic rates increased with temperature from 0.08 mg O2·g−1·h−1 at 5°C to 0.25 mg O2·g−1·h−1 at 25°C, but few differences in metabolic rates were observed among populations at any temperature. Although we found bioenergetic differences among muskellunge from these populations, they could not be explained solely in terms of thermal adaptation or previously defined genetic groupings. Energetic differences among age‐0 muskellunge have important implications for conserving existing esocid populations and managing introduced populations.

Muskellunge (Esox masquinongy) feeding habits and habitat preferences in Lake St. Clair

Muskellunge (Esox masquinongy) are an economically and ecologically important species. Yet, our understanding of their feeding habits and habitat preference is limited and incomplete. This study addressed these shortcomings with muskellunge in Lake St. Clair. Muskellunge were captured by trolling on charter boats and electrofishing. Feeding habits were determined by comparing fish consumed to abundance of fish in the lake. Habitat preference was determined by spatially analyzing collected fish catch-per-unit-effort and lake conditions such as depth and submerged aquatic vegetation coverage. Overall, 167 muskellunge were sampled and 77% of them had empty stomachs. White bass (Morone chrysops) was the most common found prey species in their diet. Moronidae was the family composing the largest portion of their diet. Muskellunge were more abundant in water with greater depth. The entire lake appears to have suitable coverage of submerged aquatic vegetation with an average of 67%. In conclusion, muskellunge consumed small amounts of the main sport fish species in Lake St. Clair and likely have minimal impacts on those populations. The majority of Lake St. Clair has the preferred habitat for muskellunge and is likely to be a contributing factor to their large population.

The food and growth of the maskinonge (Esox masquinongy) in Canadian waters

Maskinonge from three regions were studied: the Lake of the Woods district in Ontario (called Western); the Kawartha Lakes and Georgian Bay district in Ontario (Central) and the St. Lawrence River district in Quebec (Easternmm. in length. The families Percidae, Catostomidae, Ameiuridae, Centrarchidae, Hiodontidae, Esocidae and Cyprinidae were represented, along with at least one ). Examination of 202 stomachs, 81 containing food, showed the maskinonge to be a general carnivore, preying mainly on fish over 150 Cambarus. The yellow perch, Perca flavescens, was the species eaten most frequently in all three regions. A common white sucker (Catostomus commersonnii) was found in a stomach of the hybrid E. masquinongy × E. luciusmm. fork length. Specimens of a . Examination of the teeth of each specimen showed that they were being continuously replaced throughout the summer season.Rate of growth varied with sex and locality. Females had a significantly faster rate of growth, both in length and in weight, than did males. Maskinonge from the Western Region were shorter and weighed less than fish of the same age from the other two regions. Maskinonge of the Eastern and Central Regions reached the legal size of 30 inches fork length during their fifth summer, but in the Western Region they did not attain this size until their seventh summer. The length-weight relationship appears to be the same in the Eastern and Central Regions, whereas maskinonge from the Western Region tended to be heavier than those of comparable lengths from the other two regions. In all regions the length-weight relationship was a straight line when plotted logarithmically, its slope being estimated as 3.26 in the Eastern Region. Sexual maturity occurs first between the ages of three and six years, or about 575 to 800 E. masquinongy × E. lucius hybrid appeared to be infertile. They did not differ from the maskinonge specimens in their length-weight relationships but made faster growth than did the maskinonge from the same region.

Diets of muskellunge in northern Wisconsin lakes. North American Journal of Fisheries Management

The muskellunge Esox masquinongy is an important sport fish in Wisconsin and elsewhere, but more information about its diet is needed to better understand its role in aquatic systems and its effects on other fish. Stomach contents were examined for 1,092 muskellunge (226–1,180 mm total length, TL) captured in the littoral zone from 34 Wisconsin water bodies from July 1991 to October 1994. Food occurred in 34.3% (N 5 375) of the stomachs, with most (74%) containing a single item. Overall, the proportion of muskellunge with food differed significantly among seasons, with the greatest proportion occurring in fall (69.0%), followed by summer (53.5%) and then spring (25.4%). Prey items consisted of 547 fish, representing 12 families and 31 species, along with 35 nonfish items; fish composed 98% of the diet. Relative importance values of diet items varied by taxa, season, and water body, but the main food items eaten by muskellunge in each season were yellow perch Perca flavescens and white sucker Catostomous commersoni. Black basses Micropterus spp., northern pike Esox lucius, walleye Stizostedion vitreum, cyprinids, and other taxa were less common in the diet. Prey fish ranged in size from 6% to 47% of muskellunge total length and prey length increased significantly as muskellunge size increased. Yet the size of prey in proportion to muskellunge size remained the same for all sizes of muskellunge. The results of this study indicate that, if readily available, yellow perch and catostomids will compose a large proportion of the muskellunge diet. Additional studies assessing muskellunge diet among lakes having different prey community types and assessing diet in deeper offshore areas of lakes are needed to better understand the role that muskellunge play in aquatic communities.

Feeding habits and diet of the muskellunge (Esox masquinongy): A review of predatory impacts on resident biota

The Muskellunge (Esox masquinongy) is known as a voracious apex predator. In instances where muskellunge are extending their range, either through intentional or inadvertent introduction and natural range extension, concerns have been identified about the potential negative impacts on resident fishes and aquatic biota. This review has been conducted to assemble information on muskellunge predatory habits and diet as well as interspecific competition with other species.

Muskellunge prey on a wide variety of organisms but prefer other fishes. Predation is based largely on whatever species in available at the preferred size. There is a considerable amount of evidence to indicate that Muskellunge prefer soft-rayed fishes and the availability of soft-rayed prey cound determine the degree of predation on other species.

Generally, there a few definitive studies to quantify impacts (if any) of Muskellunge on other fish species. There is very little evidence to indicate that Muskellunge have a significant negative impact on populations of other popular sport fish species including Walleye, Largemouth Bass and Smallmouth Bass. In fact, there are numerous instances where these fish species successfully co-habit the same waterbody. Since Muskellunge seldom occupy coldwater habitats, their interactions with coldwater fishes (i.e. salmonids and coregonids) are poorly understood. This is an area which requires future study.

Potential negative impacts of Muskellunge on other fish species are probably related to the size of waterbody and the composition of the resident fish community. Larger waterbodies and those waters having a diverse forage fish community seem to be relatively unaffected by the presence of Muskellunge. The presence/abundance of soft-rayed fish species likely reduces the predation on other resident fish species.

Other fish species can have negative impacts on the Muskellunge. Northern Pike are known to have a competitive advantage over Muskellunge where they coexist. Young Muskellunge are also subject to predation by other fishes including Largemouth Bass, Yellow Perch, Rock Bass and Walleye.

Based on this literature review several recommendations are offered. These are related to initiating more quantified studies to document impacts (if any) when Muskellunge are introduced or become established in new waters, utilizing new state-of-the-art techniques to determine diets and predatory-prey relationships amongst a broader range of fish community types (including salmonids and species at risk), and developing efforts to improve the public perception of Muskellunge.

Using movements and diet analysis to assess effects of introduced muskellunge on Atlantic salmon in the St. John River, New Brunswick

The muskellunge was introduced in the Saint John River system from stockings in a headwater lake in the 1970s. They have migrated down the system as far as the river’s first dam, Mactaquac Hydroelectric Facility, at Fredericton and appear to have established several reproducing populations along the river. This exotic invader represents a potential threat to the severely depleted Atlantic salmon stocks in the river. We radio-tracked muskellunge over a 2- year period in the middle reaches. Home ranges extended to ~100 km in both riverine and lacustrine areas, including 78% of individuals translocated upstream of the dam making their way back through the dam successfully. Downstream of the dam, home ranges were <25 km. No spawning areas were detected. An isotope analyses of diet indicated that the large sub-adults and adults had established the greatest proportion of their biomass in a more 15N depleted environment typical of areas farther upstream. Isotope mixing models could not accurately determine the proportion of Atlantic salmon smolts that may have been consumed by muskellunge, but anadromous salmon had £7% probabilities of being in the diet. A bioenergetics model suggested £5% of the annual food intake by muskellunge occurs during the smolt out-migration period. For the Saint John River, the impacts of growing numbers of muskellunge are multi-faceted creating a complex management challenge. Muskellunge appear to minimally increase predation risk for Atlantic salmon smolts while their increasing numbers are creating a growing recreational fishery and potential threat to the native fish community and ecosystem.