Empirical estimation of recreational exploitation of burbot, Lota lota, in the Wind River drainage of Wyoming using a multistate capture–recapture model

Abstract

Burbot, Lota lota (Linnaeus), is a regionally popular sportfish in the Wind River drainage of Wyoming, USA, at the southern boundary of the range of the species. Recent declines in burbot abundances were hypothesised to be caused by overexploitation, entrainment in irrigation canals and habitat loss. This study addressed the overexploitation hypothesis using tagging data to generate reliable exploitation, abundance and density estimates from a multistate capture–recapture model that accounted for incomplete angler reporting and tag loss. Exploitation rate μ was variable among the study lakes and inversely correlated with density. Exploitation thresholds μ 40 associated with population densities remaining above 40% of carrying capacity were generated to characterise risk of overharvest using exploitation and density estimates from tagging data and a logistic surplus-production model parameterised with data from other burbot populations. Bull Lake (μ = 0.06, 95% CI: 0.03–0.11; μ 40 = 0.18) and Torrey Lake (μ = 0.02, 95% CI: 0.00–0.11; μ 40 = 0.18) had a low risk of overfishing, Upper Dinwoody Lake had intermediate risk (μ = 0.08, 95% CI: 0.02–0.32; μ 40 = 0.18) and Lower Dinwoody Lake had high risk (μ = 0.32, 95% CI: 0.10–0.67; μ 40 = 0.08). These exploitation and density estimates can be used to guide sustainable management of the Wind River drainage recreational burbot fishery and inform management of other burbot fisheries elsewhere.