Survival and Condition of Cold-Banked Juvenile Walleyes

Abstract Over their broad latitudinal distribution in nature, Walleye Sander vitreus have adapted to survive long winters in ice-covered lakes and for more than 5 months when water temperatures are less than required for growth (10°C). Thus, our hypothesis is that hatchery-reared fall-fingerling Walleyes may be maintained in hatchery confinement at low temperature for relatively long intervals with minimal requirement for feed and maintenance, i.e., cold banked (CB). Little information has been published, however, on survival and condition of CB fish to judge its merits. In this study, survival and condition of three cohorts (N = 1,538) of feed-trained juvenile Walleyes (181–192 mm total length, 47–58 g) are described after overwintering for 125–153 d in indoor culture tanks that were supplied with lake water of ambient winter temperature and pelleted feed. The mean for survival of three tanks of CB fish in each cohort was 85.8, 91.7, and 98.6% at corresponding mean water temperatures of 7.6, 8.3, and 6.8...