The effect of temperature on growth of juvenile bloater

The bloater (Coregonus hoyi), which feeds mainly on invertebrates and in turn is eaten by lake trout (Salvelinus namaycush) and burbot (Lota lota), is a major trophic integrator in coldwater ecosystems in the upper Great Lakes. To better understand their thermal niche and habitat distribution, we acclimated groups of yearling bloater to 3, 5, 10, 15, 20, or 25°C and then fed them ad libitum for 35 days. Bloater increased in length and weight at all of the test temperatures and at the end of the study were heaviest and longest at 15–20°C. The specific growth rate was highest at 20°C and progressively lower at 15, 25, 10, 5, and 3°C. A curve fitted to the specific growth rate data indicated that the optimum temperature for growth was 18.6°C. Our results are in agreement with other published information on the thermal ecology of juvenile bloater.