Fisheries Management and Ecology最新文献

Composition, size distribution, structure, and function of deep-sea marine communities must be understood before they are impacted by anthropogenic effects. The deep-sea ecosystem of the Colombian Caribbean Sea is unexploited with no fishing activity ever registered. We quantified the current state of the marine community using body size distribution (size-spectra), size-based indicators, minimum length (L_MIN), maximum length (L_MAX), average length (L_mean), standard deviation of length (L_SD), 10th and 90th percentiles of the length distribution, Shannon–Wiener diversity (H′), and Pielou's evenness (J′) to generate a baseline of potential ecological indicators that contribute to management and conservation of the Colombian bento-demersal community of deep-sea marine ecosystem. Sampling was in the Colombian Caribbean Sea at 58 stations during four samplings in August and December 2009, 21 stations in March and May 2010, and 45 stations from August to December 2020, using the swept area method, at depths of 200–550 m. Catches included >50% families and species of fish, followed by 27 families (30%) and 33 and species (37%) of crustaceans. Chondrichthyes included 14% families and 9–11% species. Cephalopods included 2–3% families and 1–4% species. Size-spectra analysis confirmed expected values for unexploited communities in three sampling years for teleostei, crustacea, and whole community.

Few studies have acknowledged and quantified the economic contribution in expenditures of recreational fisheries. Additional economic value attributed to fishers' willingness to pay (WTP) for recreational fisheries in excess of expenses was estimated for 33 countries in Europe. Benefit transfer was used in a meta-regression analysis of 184 studies and 1001 observations of WTP per day for recreational fisheries. Most studies of fishing were in the USA, but also in Europe, Australia, New Zealand, South America and Canada. Mixed-effects regression models were estimated with income, climate variables, population density and study characteristics as explanatory variables. Income and temperature positively affected WTP per day. Benefit transfers with these variables and different transfer methods among European countries showed that the estimated total WTP could amount to 11.4 billion USD (purchasing power parity corrected to 2020 prices). Variation in WTP per day was large, and ranged 9–62 USD among countries and transfer methods. For several countries, WTP for recreational fisheries exceeded 0.1% of gross domestic product.

The age-structured assessment model available in the MSEtool R package assesses stock status and exploitation for varying data availability, from limited to rich datasets. We investigated model accuracy in relation to data availability, population exploitation levels, initial population assumption and fishery selectivity misspecification. Estimates were accurate in all conditions when data were available for a stock in an unfished state. However, for estimates to be accurate without complete exploitation data, total catch and abundance index data needed to span more than two stock generations. When the data time series was shorter than two generations, fishery mean lengths spanning one generation improved relative estimates (e.g. depletion), but precise estimates of unfished recruitment required fishery age- or length-structured data.