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Sharks play a key role in the structure and functioning of marine ecosystems. More ecological information is essential to implement responsible management and conservation actions on this fauna, particularly at a regional level for threatened species. Mustelus mustelus is widely found in the eastern Atlantic Ocean and catalogued as "Vulnerable" by the IUCN European assessment. In this study, data on the distribution and population structure of this species across the islands of the Canarian archipelago, located along an east to west gradient in the north‐eastern Atlantic, were collected by taking advantage of "Local Ecological Knowledge," in terms of sightings in coastal waters and long‐term imprints on the local gastronomic heritage, and decadal fisheries landings. Both sources of quantitative data (sightings and fisheries landings) demonstrated that adults of M. mustelus has a significantly larger presence in the eastern and central, than in the western islands of the archipelago. This is also reflected on local gastronomic legacies, with a larger number of recipes in the eastern and central islands. Adult smooth‐hound sharks were significantly more observed in sandy and sandy‐rocky bottoms, with individuals seen throughout the entire year, whereas juveniles aggregate on very shallow waters in spring and summer. Such aggregations require a special management strategy, as they play a key role in critical life stages; these sites should be protected from human perturbations. We also suggest a temporal fishing ban between April and October, when individuals tend to concentrate on nearshore waters. Because of the large differences in presence of this shark among the Canary Islands, management of the species should be adapted to the specific peculiarities of each island, rather than adopting a management policy at the entire archipelago‐scale. Overall, this study sets the basis for further investigation to promote conservation of this vulnerable shark in the study region. [ABSTRACT FROM AUTHOR]

Batoids, distributed from shallow to abyssal depths, are considerably vulnerable to anthropogenic threats. Data deficiencies on the distribution patterns of batoids, however, challenge their effective management and conservation. In this study, we took advantage of the particular geological and geomorphological configuration of the Canary Islands, across an east‐to‐west gradient in the eastern Atlantic Ocean, to assess whether patterns in the occurrence and abundance of batoids varied between groups of islands (western, central, and eastern). Data were collected from shallow (<40 m, via underwater visual counts and by a local community science program) and deep waters (60–700 m, via ROV deployments). Eleven species of batoids, assessed by the IUCN Red List of Threatened Species, were registered, including three "Critically Endangered" (Aetomylaeus bovinus, Dipturus batis, and Myliobatis aquila), three "Endangered" (Gymnura altavela, Mobula mobular, and Rostroraja alba), two "Vulnerable" (Dasyatis pastinaca and Raja maderenseis), and two "Data Deficient" (Taeniurops grabata and Torpedo marmorata). Also, a "Least Concern" species (Bathytoshia lata) was observed. Overall, batoids were ~1 to 2 orders of magnitude more abundant in the central and eastern islands, relative to the western islands. This pattern was consistent among the three sources of data and for both shallow and deep waters. This study, therefore, shows differences in the abundance of batoids across an oceanic archipelago, likely related to varying insular shelf area, availability of habitats, and proximity to the nearby continental (African) mass. Large variation in population abundances among islands suggests that "whole" archipelago management strategies are unlikely to provide adequate conservation. Instead, management plans should be adjusted individually per island and complemented with focused research to fill data gaps on the spatial use and movements of these iconic species. [ABSTRACT FROM AUTHOR]

Aim: The influence of niche and neutral mechanisms on the assembly of ecological communities have long been debated. However, we still have a limited knowledge on their relative importance to explain patterns of diversity across latitudinal gradients (LDG). Here, we investigate the extent to which these ecological mechanisms contribute to the LDG of reef fishes. Location: Eastern Atlantic Ocean. Taxon: Reef‐associated ray‐finned fishes. Methods: We combined abundance data across ~60° of latitude with functional trait data and phylogenetic trees. A null model approach was used to decouple the influence of taxonomic diversity (TD) on functional (FD) and phylogenetic (PD) diversity. Standardized effect sizes (SES FD and SES PD) were used to explore patterns of overdispersion, clustering and randomness. Information theoretic approaches were used to investigate the role of large‐ (temperature, geographic isolation, nitrate and net primary productivity) and local‐scale (human population and depth) drivers. We further assessed the role of demographic stochasticity and its interaction with species trophic identity and dispersal capacity. Results: Taxonomic diversity peaked at ~15°–20°N, with a second mode of lower magnitude at ~45°N; a pattern that was predicted by temperature, geographic isolation and productivity. Tropical regions displayed a higher proportion of overdispersed assemblages, whilst clustering increased towards temperate regions. Phylogenetic and functional overdispersion were associated with warmer, productive and isolated regions. Demographic stochasticity also contributed largely to community assembly, independently of ecoregions, although variation was dependent on the trophic identity and body size of species. Main conclusions: Niche‐based processes linking thermal and resource constraints to local coexistence mechanisms have contributed to the LDG in reef fishes. These processes do not act in isolation, stressing the importance of understanding interactions between deterministic and stochastic factors driving community structure in the face of rapid biodiversity change. [ABSTRACT FROM AUTHOR]

Seagrass meadows are crucial habitats on nearshore areas, which are exposed to human disturbances that frequently cause seagrass loss. Although demographic and mapping data have been widely used in long‐term monitoring programmes, the integration of multi‐locus genotype data through time remains rare.The present work links, for the first time, landscape, demographic, and genetic data for a seagrass, so as to explore long‐term responses to persistent human impacts. The temporal patterns in meadow area, shoot density, and clonal and genetic diversity of three Cymodocea nodosa meadows were compared: in one meadow directly affected by the construction of an industrial port and in two control areas. The hypothesis tested was that seagrass deterioration and subsequent habitat loss at the affected meadow would be associated with a reduction of seagrass clonal and genetic diversity.The results show significant reductions in both meadow area (from approx. 21 to 1.5 ha) and shoot density (from approx. 1,800 to 400 shoots per m2) at the impacted meadow, with concurrently reduced clonal and allelic richness (by approx. 22%), as well as heterozygosity (HLmean, approx. 21%; Hobs, approx. 12%). These descriptors, however, remained stable, or even increased, in the controls.Importantly for seagrass management, multi‐disciplinary analysis made it possible to link slower, large‐scale, landscape and genetic degradation processes with faster demographic deterioration on an intermediate meadow scale. Multi‐locus genotype data were also crucial for revealing long‐term degradation processes at the genetic level, which is undetectable by traditional monitoring techniques.In summary, this holistic approach provides a valuable framework for long‐term seagrass monitoring programmes to detect cumulative signals of seagrass meadow degradation across a range of scales. [ABSTRACT FROM AUTHOR]

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