(Français) Contribution de la station piscicole de Lachine à l’étude du maskinongé No. 1

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En 1949, sur la recommandation de l’Association des Pêcheurs et des Chasseurs du lac Saint-Louis, et sous l’impulsion de Ted Glendenning, le Département de la Chasse et de la Pêche entreprenait un expérience, sous la direction du Docteur Gustave Prévost, à savoir s’il nous était possible de pratiquer l’élevage du maskinongé en s’alimentant de l’eau naturelle du fleuve et dont le but était le repeuplement des eaux de la région de Montréal.

Contribution de la station piscicole de Lachine à l’étude du maskinongé – Juillet 1961

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.

Age et croissance du masquinonge (Esox masquinongy) dans quatre lacs du Québec

Specimens were taken from two lakes where maskinonge is indigenous: Lake Saint-François (188 specimens) and Lake Saint-Louis (109 specimens), and from two others where it was introduced: Lake Saint-Joseph (44 specimens) and Lake Ouareau (12 specimens). The ages were determined from scales reading. Growth in length and in weight was identical for males and females from lakes Saint-François and Saint-Louis and there was no difference in growth observed in these same two lakes. Growth, however, was very different in lakes Saint-Joseph and Ouareau: during their 11th summer for instance, maskinonges from lakes Saint-François and Saint-Louis measured 1112 g. Our results are compared with those in the literature. mm and weighed 5669 g and those from Lake Ouareau measured 914 mm and weighed 8854 g whereas those from Lake Saint-Joseph measured 1024 mm, and weighed 10,511.

Effects of angler harvest on adult muskellunge growth in Escanaba Lake, Wisconsin, 1956-2016

The behavior of anglers targeting Muskellunge Esox masquinongy in Wisconsin has changed over time from being harvest oriented to catch‐and‐release oriented. Our objectives were to use the long‐term tagging data set (1956–2016) available on the Muskellunge population of Escanaba Lake, Wisconsin, to characterize sex‐specific age structure, length at age, and survival in relation to a potential change in angler harvest. We hypothesized that (1) angler harvest has changed over time, (2) age structure and length at age have changed in relation to the change in angler harvest, and (3) annual survival has changed over time in relation to changes in angler harvest. A breakpoint analysis revealed distinct changes in angler total harvest over time, occurring in 1995 and 2011. Muskellunge harvest (1956–1994) was significantly higher (29.7 ± 15.9 fish/year [mean ± SD ]) than that observed during 1995–2010 (6.5 ± 2.9 fish/year) and 2011–2016 (0.83 ± 1.1 fish/year). Sex‐specific growth did not differ between fishery type (i.e., high and low harvest). However, there was evidence that the asymptotic length of female Muskellunge was higher during the high harvest fishery. The top model in program MARK suggested that survival (S ) differed by fishery type; i.e., S high ± SD = 0.72 ± 0.01 and S low ± SD = 0.99 ± 0.006. Exploitation was the primary component of annual mortality. Natural and discard mortality could not be differentiated. Natural and discard mortality was 9.2 ± 11%/year during the high harvest fishery and 4.9 ± 5.9%/year during the low harvest fishery. Reductions in Muskellunge exploitation led to increased survival and no apparent change in length at age. These results from Escanaba Lake suggest that the lack of harvest leading to an unexploited Muskellunge fishery may result in population stability, improved age structure distribution, and adult survival, but could potentially hinder management actions meant to further increase population density or growth potential to trophy size.

Historical trends in body growth of five Ontario muskellunge populations

Muskellunge management (Esox masquinongy) in Ontario has primarily focused on harvest control through minimum size limits, requiring information on the growth potential, responses and variability of populations. We examined historical muskellunge body growth trends as recorded in the cleithrum bone from five muskellunge populations, including two populations with extended data sets (overall n=456). Two measures were digitally collected – an index of annual growth and cleithrum size at age eight – and linearly regressed against log-transformedmean daily summer temperatures. There were no significant correlations between temperature and annual growth (p = 0.120 to 0.762)

Relative weight as a condition index for muskellunge

Weight-length data were obtained for 45 muskellunge (Esox masquinongy) populations (N=4,343) from 16 states to develop a standard weight (Ws) equation that would allow calculation of relative weight (Wr) values. We developed a 75-percentile equation using the regression-line-percentile method. The proposed equation, based on all fish combined, is log10 Ws(g) = −6.066 + 3.325 log10TL(mm). The English equivalent for this equation is log10Ws(lb) = −4.052 + 3.325 log10TL(in). This equation is useful for 38 cm and longer muskellunge, and there was no evidence of consistent trends in increasing or decreasing Wr with increasing fish length. Because muskellunge can be sexed based on external characteristics, we also developed separate Ws equations for male and female muskellunge. However, Wr values calculated with the combined equation were quite similar (Wr values within 1–2) to those for values calculated from the female-only Ws equation. Values calculated with the male-only Ws equation were slightly more variable.

Comparison of growth rates for native and hatchery-stocked populations of Esox masquinongy in Nogies Creek, Ontario

Recent techniques have contributed to a more accurate determination of age by the scale method and a new growth curve for the maskinonge in Nogies Creek has been constructed. Hatchery fish, planted as fingerlings, show similar growth for 4 summers after which their growth rate rapidly falls away from that for the native fish. The hatchery fish require 3 years more than the native fish to reach legal length. A reduction in the annual growth increment for tagged fish ranges from 25% (age IV) to 80% (age VI) of that attained by untagged fish. No significant divergence in the length–weight relationship was observed in the slower growing hatchery fish.

Comparison of the use of cleithra to the use of scales for age and growth studies

Cleithra and scales were obtained from each of 110 muskellunge captured by anglers in the Niagara River. The results obtained from cleithral age‐and‐growth analysis were compared to those from a similar scale analysis. Ages agreed on 87% of the sample. When ages disagreed, it was most often judged that the cleithral age was correct. Fish older than IX+ years could not be aged from scales, but cleithra were useful for fish as old as XVI+ years. Lengths back‐calculated from the two techniques were statistically (95% level) equivalent at all ages except age I.