Growth, ingestion rates and metabolic activity of walleye in lakes with and without lake herring
Abstract:Growth efficiencies, ingestions rates and activity levels of walleye Sander vitreus were compared in lakes with and without lake herring Coregonus artedi. Yellow perch Perca flavescens were the main prey in lakes without lake herring. Walleye were sampled in September and October from 38 lakes in Ontario in 1998 and 1999, using multimesh monofilament gillnets. Ingestion rates were estimated from annual increments in somatic mercury and body mass, and the mercury content of yellow perch and lake herring. Walleye had higher growth efficiencies, and lower ingestion and activity rates in lakes with lake herring. Lake herring grow larger than yellow perch and therefore could provide more profitable prey for larger walleye. The results are consistent with optimal foraging theory that predicts that walleye feeding on optimal prey sizes should grow more efficiently, if the ratio of feeding benefit (energy) to cost (search and seizure) is a function of the ratio of predator and prey size.
Document Type: Regular Paper
Affiliations: 1: Erindale College, Biology Department, University of Toronto at Mississauga, 3359 Mississauga Road North, Mississauga, Ontario, L5L 1C6, Canada, 2: Cooperative Freshwater Ecology Unit, Department of Biology, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada and 3: Ontario Ministry of the Environment, Biomonitoring Section, 125 Resources Road, Etobicoke, Ontario, M9P 3V6, Canada
Publication date: November 1, 2004