Evaluating recreational fisheries for an endangered species: a case study of taimen,

Abstract: Understanding the tradeoff between exploitation and conservation is difficult in data-poor situations, which are typical for most recreational fisheries, even in developed countries. In a developing country where the target species is en-dangered, the stakes are higher and the management resources are fewer. We combined a mark–recapture experiment, life history invariants, and meta-analysis to parameterize a delay-difference model for a population of the endangered giant Eurasian trout (taimen, Hucho taimen) in northern Mongolia. The model allowed us to evaluate the impacts of a recrea-tional fishery for taimen based on a suite of population characteristics including equilibrium abundance, biomass, and mean weight. The Bayesian framework and Monte Carlo simulations combine disparate sources of information while keep-ing track of uncertainty as it propagates through the model. In the case of taimen in the Eg–Uur watershed, the existing catch–release recreational fishery has likely reduced taimen abundance, biomass, and mean weight by less than 10 % com-pared with levels predicted in the absence of recreational fishing. In comparison, if all taimen caught in this fishery were retained (as they are elsewhere in Mongolia), there is a 57 % chance that such harvest levels, if maintained, would lead to the eventual extirpation of the population. Résume ́ : Il est difficile de comprendre le compromis entre l’exploitation et la conservation dans les pêches sportives lors-qu’il y a peu de données, ce qui est très souvent le cas, même dans les pays développés. Dans un pays en voie de dével-oppement lorsque l’espèce cible est menacée, les enjeux sont plus importants et les ressources de gestion moindres. Nou