Growth Response of Juvenile Walleyes after Cold Banking

Abstract

AbstractThe natural geographical range of Walleye Sander vitreus extends to northern latitudes where lakes are often ice covered for 8 months. Their adaptation to long intervals at low temperature provides aquaculturists the opportunity to purposefully maintain Walleyes in confinement for several months at low temperatures with minimal feeding, i.e., a protocol termed cold banking (CB). To be successful, CB should not result in substantial mortality or loss of body condition, and after CB interval, fish should show a strong positive growth response. The objective of this study was to determine the growth response and condition of fingerling Walleyes cold banked, for 125 d at mean temperature of 6.9°C, in a 76‐d post‐CB (PCB) interval. Survival in the CB interval was 99%, and means of initial and final length, weight (4.5% loss), and relative weight (Wr) were not significantly different. After a 4‐d transition from 5.1°C to 19.2°C, some CB Walleyes were cultured in a water reuse aquaculture system at mean temperature of 22.6°C for 76 d. In the PCB interval, fish length increased 31%, and weight 170%, and Wr was 99.8. This study demonstrates that CB did not result in substantial mortality or weight loss, and Walleyes show a strong PCB growth response after cold banking.