Small-scale fisheries play a critical role in food security and contribute to nearly half of reported global fish catches. However, the status of most small-scale fisheries stocks is still poor. In data-limited situations, length-based methods have been widely applied to estimate reference points and to understand stock status. This study applied three different length-based assessment methods (length-based indicators—LBI, length-based spawning potential ratio—LBSPR, and the length-based Bayesian biomass approach—LBB) to predict fisheries stock sustainability in the Azores. Overall, the three methods showed robustness for 15 out of 18 stocks assessed and agreed on their exploitation status. The results showed that 45% of the Azorean stocks were classified assustainable stocks, 33% possiblerebuilding/overfishedand 22%overfishing/overfishedstock status. Sensitivity analysis showed that biases on the source of initial life-history parameters, especially the asymptotic length (L∞) and the ratio of natural mortality and growth coefficient (M/k), have a stronger influence on the reference points of conservation of mature individuals (LBI), spawning potential ratio and fishing mortality (LBSPR) and the biomass relative to the maximum sustainable yield (LBB). Furthermore, sensitivity analysis indicated that, among the three methods, LBI is more robust. Our findings provide some management recommendations such as (1) catches and effort should be reduced; (2) minimum landing size should be increased; (3) minimum hook size should be increased, to be applied mainly for those stocks classified as possiblerebuilding/overfishedandoverfishing/overfishedstock status.Graphical abstract

Elasmobranchs are a vulnerable resource, more susceptible to overfishing than most teleosts, and their assessment is complicated due to a general lack of information about their fisheries, biology and ecology. This study aimed to analyse all fishery and survey data available for elasmobranchs caught over the past c. 25 years around the Azores (NE Atlantic) to provide a baseline information, which can be used to inform stock assessment and management strategies. Elasmobranch species covered pelagic, benthopelagic and demersal habitats, from shallow to deep-water strata in areas around the islands and seamounts. These species are taken accidentally as by-catch of three main fisheries: swordfish fishery, black scabbardfish fishery and demersal bottom longline fishery. The latter represents one of the most important fishing activities in the Azores, and frequent elasmobranch by-catches include Raja clavata, Galeorhinus galeus, Deania calcea, D. profundorum, Etmopterus pusillus and E. spinax. A slight reduction in the abundance indices of these species was observed, despite the implemented technical measures (e.g. minimum size, zero catch). Little is known about resource dynamics for the Azorean region and no analytical assessments have been conducted. This study highlights the vulnerability to overfishing of these resources and the urgent need to develop management strategies.

Small-scale fishing is a multi-gear activity that focuses on a wide range of species. As there is a considerable diversity of species, it is often difficult to keep track of all of those that are caught, and due to the lack of data or poor quality, most stock statuses are currently unknown around the world. Therefore, local ecological knowledge provided by fishers has been regarded as a valuable source of information to bridge these crucial gaps. This study assesses the vulnerability status of 22 fishing stocks in the Azores, through productivity and susceptibility analyses (PSAs) using two independent data sources: conventional scientific knowledge and fishers’ knowledge data. We created four PSAs with separate and integrated data sources. Although we found some differences in the vulnerability scores and rankings, the risk outputs of the PSAs using independent and integrated sources of data generally match, reflecting a similar pattern trend. The findings of this work suggest that integrating FK may be an alternative to provide good fisheries’ assessment outcomes in the absence of CSK. Overall, this research supports the inclusion of fishers’ knowledge in vulnerability assessments as not only beneficial in the absence of data, but also as a supplement to data that can improve management advice.