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The global overfishing scenario of the historically exploited marine stocks have generated concern and encouraged the search for new potentially exploitable fisheries resources. In this sense, shrimps are potential alternative resources to be exploited, given their high diversity and stock resilience. This study had an objective to estimate life-history traits and analyse yield and abundance fishing levels to see whether Plesionika edwardsii shrimp is vulnerable to overexploitation or not in the mid-North Atlantic (Azores region, ICES Subdivision 10a2). The females showed larger L∞ (asymptotic length) and k (coefficient of growth; L∞ = 27.3 mm, k = 0.75 year−1) than did males (L∞ = 24.58 mm, k = 0.73 year−1). The mortality rates of males (Z = 1.00 year−1; M = 0.84 year−1) and females (Z = 0.92 year−1; M = 0.85 year−1) were very similar. In terms of longevity, the males (3.47 year−1) survived longer than did females (3.34 year−1). Depletion experiments showed a fast and straight-forward decline of CPUEs (3, 5 and 9 days), confirming a low mobility and vulnerability to high fishing efforts. The maximum sustainable yield (MSY) estimates (5.4–10.7 tonnes (Mg) year−1) showed a low annual sustainable catch. These values combined with the life-history characteristics indicated that this stock is less resilient and highly vulnerable to overfishing.

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 as sustainable stocks, 33% possible rebuilding/overfished and 22% overfishing/overfished stock 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 possible rebuilding/overfished and overfishing/overfished stock status. Graphical abstract

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.

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 ...

Simple Summary The growing scarcity of continental shelf and epipelagic oceanic fishes has led to commercial fishing in deeper waters. With this spatial expansion in fishing efforts, some vulnerable deep-sea species have been increasingly captured. To reduce fishing-induced impacts on these resources, information on population traits is required by fishery scientists to produce adequate management advice. In the Northeast Atlantic, the common mora Mora moro has become the main fish species caught by bottom longliners operating in deep waters between 600 and 1200 m. Information about the biology and exploitation status of this species is scarce. This study unravels and highlights important and crucial aspects of the habitat preferences, life-history traits (sex ratio, timing of reproduction, size at maturity, growth pattern, and mortality rates), size structure, and abundance of the M. moro based on scientific surveys and commercial fisheries in the Azores region. Results highlight its vulnerability to overfishing due to its large size, slow growth, low natural mortality, long life span, and late maturity. Abstract With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

Survey data from the Azores is used for fisheries stock assessments under the ICES Working Group on the Biology and Assessment of Deep-sea Fisheries Resources (WGDEEP) covering deep open ocean areas. The Azores research cruise using bottom longlines for abundance estimation is probably unique in the Northeast Atlantic Ocean. This study analyzed data from annual Azorean bottom longline surveys (ICES subdivision 10a2) from 1996 to 2018 to calculate abundance indices of commercial demersal species, to estimate the statistical significance of the annual changes in the abundance estimates, and to examine the possible factors that cause this variability. The catch rates of these surveys appear to provide accurate indices of abundance for most of the commercially important demersal species. The observed inter-annual variability of the survey abundance estimates can be explained by survey effort distribution, fishery dynamics, aggregation patterns of some species, habitat preferences, fish movements, and environmental effects. However, other factors can affect these estimates (soak time, gear saturation and competition for hooks) and we recommend that additional studies be undertaken to understand these effects.

This paper summarises the detailed information on catch, fork length, weight, sex and maturity of alfonsinos Beryx splendens and Beryx decadactylus collected from targeted surveys in Azores waters, complemented by fishery data, over the past c. 20 years. To date, it was not possible to define if the Azorean component of the population can be considered as a discrete local management unit. The reason for this is the lack of available information for these resources covering the entire spatial distribution of the species in the North Atlantic Ocean. Additionally, there are some conflicts between the different genetic results available, poor understanding about the species movements and data from the Azores show some discrepancies in aspects of reproduction. Consequently, there is no analytical assessment for this resource and the stock of Beryx spp. is currently managed based on the precautionary approach. Outputs of recent analyses are presented in this study and possible assumptions and strategies for the assessment are discussed.

To obtain important baseline information about population dynamics and to provide valuable insights about the possible effects of artisanal fishing on the demersal fish community, this study had three specific objectives: (1) to update the annotated list of demersal teleost species occurring in the Azores (mid-North Atlantic); (2) to describe their depth distribution and related fishery information; and (3) to evaluate annual changes in their observed abundance and length composition. To do this, a time series with about 25 years of scientific data from the commercial fishery and surveys was analyzed. The demersal teleost community was represented by 213 species, predominantly deep-water species, reflecting the main marine habitat in the Azores region. Fishery takes place mainly in the intermediate strata (200–600 m), where the most commercially important species occur. No changing in the fork length (LF) distribution toward small individuals caused by size-selective fishing was detected in this study. The high variability observed in the LF data indicates the need for more accurate studies considering alternative statistical analyses (e.g., generalised linear models) to examine the possible factors (e.g. depth coverage, gear configuration, soak time, and fishing area) that cause this variability. On the other hand, the abundance indices of some commercially important species appear to have declined (Phycis phycis, Pontinus kuhlii, Conger conger, Beryx splendens and B. decadactylus), while others appear to be more stable (Helicolenus dactylopterus) or even increasing (Mora moro). Although the available data are insufficient for a formal assessment on the status of exploited populations, the long-term analysis of commercial landings and survey data was used as a basis to assess deep sea demersal teleost fisheries of the Azores, under a precautionary approach.