Examination of Muskellunge overwinter survival and growth in an earthen extensive culture pond

Abstract

The demand to produce larger Muskellunge to meet stocking purposes and objectives has required hatchery facilities to hold these fish through multiple life stages. Rearing of advanced Muskellunge fingerlings at the North Platte Hatchery required insertion of a passive integrated transponder tag (PIT), which also created an opportunity to track the growth and survival of these fish that were held overwinter in an extensive culture pond. This study PIT tagged 806 fingerling Muskellunge in October 2021 that were placed in a 0.1‐ha earthen pond. In March 2022 the pond was drained, and individual survival and growth were recorded. The observed overwinter survival (91.9%) was satisfactory to meet most production goals, but observed growth was minimal (21.7 ± 0.2 mm). The fall mean length of surviving Muskellunge (267.8 ± 0.9 mm) was significantly greater (t = 5.12; p ≤ 0.001) than the fall mean length of overwinter mortalities (251.4 ± 3.1 mm). Differential growth was observed with smaller individuals exhibiting greater growth during the winter, which dampens length variability within the stocked cohort. Future use of extensive culture ponds for advanced age‐1 Muskellunge production should consider the lengths desired by managers along with the associated costs of alternative production methods. This study provides expectations of overwinter survival and growth for these hatchery products.