© 2006 International Council for the Exploration of the Sea
Variation in the catchability of yellow perch (Perca flavescens) in the fisheries of Lake Erie using a Bayesian error-in-variable approach
a Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University Blacksburg, VA 24061-0321, USA
b Ontario Commercial Fisheries' Association Box 2129, 45 James Street, Blenheim, ON N0P 1A0, Canada
c Department of Integrative Biology, University of Guelph Guelph, ON N1G 2W1, Canada
*Correspondence to Y. Jiao: tel: +1 540 2315749; fax: +1 540 2317580. e-mail: yjiao{at}vt.edu.
Catch per unit effort (cpue) from fisheries, and abundance or biomass indices from fishery-independent surveys are often used to infer the dynamics of exploited populations. To do this, cpues and survey indices are usually assumed to be proportional to population size or biomass. Four sources of data on the cpue of yellow perch (Perca flavescens) in Lake Erie were available to evaluate this assumption: commercial gillnet and trapnet fisheries, an angling fishery, and a fishery-independent gillnet survey. The relationships between fisheries cpue and population biomass (estimated from an age-structured model), and between fisheries and survey cpues were analysed by error-in-variable (EIV) models because of the absence of independent estimates of population size. Cpues were not proportional to population size, estimated by biomass. Catchabilities varied widely among fisheries (gear types), time period, and areas (management units) within Lake Erie. A spatial EIV model showed that the migrations among management units were considerable. The whole-lake spatial EIV model showed that cpues were not proportional to population size.
Keywords: Bayesian, catchability, error-in-variable, Lake Erie, yellow perch
Received 15 February 2006; accepted 16 July 2006.