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Although many shark species display predictable and seasonal aggregations related to breeding activities, few studies have reported direct evidence of reproductive interactions of large sharks. In this context, the present study reports the first evidence of mating scars in female tiger sharks Galeocerdo cuvier at the Fernando de Noronha Archipelago (FEN), an oceanic remote insular system in the South Atlantic Ocean. Results from the records of seven wounded females suggest that mating activity may occur between February and August. These females measured between 267 and 372 cm in total length, which is aligned with previous studies reporting size at sexual maturity for Atlantic tiger sharks. Although some females exhibited healed wounds, three of them had fresh, open wounds. One of the females also had a swollen and red cloaca. We also report the first presumably gravid female tiger shark for the region. Although sporadic, the observations herein reported indicate the importance of FEN for tiger shark reproduction in western equatorial Atlantic waters. This finding is especially relevant as FEN has been identified as an important genetic hotspot for tiger sharks, with the largest global genetic diversity for the species. [ABSTRACT FROM AUTHOR]

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]

The bentfin devil ray (Mobula thurstoni) is a migratory elasmobranch species with a wide distribution range. Despite the recent increase in mobulid research, critical habitats and home ranges are still being identified for these threatened species. In the present study, photo and video records opportunistically gathered by SCUBA diving effort were used to identify individuals and habitat usage by M. thurstoni in a marine protected area in the western equatorial Atlantic Ocean, Fernando de Noronha Archipelago (FNA). The bentfin devil ray was identified in five distinct records, in different years and sites around the archipelago. All the males showed developed claspers, suggesting mature individuals using the area. The UNESCO heritage site of FNA is considered an area of high biological importance, containing essential habitats for several species of fish, turtles and marine mammals. However, habitat usage by devil ray species is poorly reported in the region; therefore, the present study presents the first report of M. thurstoni at FNA, which adds the fifth mobulid ray species recorded in the region. Additionally, these results correspond to the second record of living specimens of M. thurstoni in Brazilian jurisdictional waters, highlighting new information on the species' distribution and the home range of mobulids in Brazil. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyse the feeding habits and trophic interactions between four oceanic predatory fish around the Fernando de Noronha Archipelago (FNA), Brazil, in the western equatorial Atlantic (3.86°S/32.42°W), internationally recognized as an environment of high economic and ecological value. For this purpose, biological samples of yellowfin tuna (Thunnus albacares), wahoo (Acanthocybium solandri), barracuda (Sphyraena barracuda) and dolphinfish (Coryphaena hippurus) were collected for stomach content and stable isotope analysis. Values of the index of relative importance revealed varied diets, with a strong presence of teleost fishes (Diodontidae and Exocoetidae) for all species, with yellowfin tuna having a greater diversity of food items. Despite being generalists/opportunists, the feeding strategy of these predators showed a tendency towards a specialized diet in the use of the available resources around the FNA. They presented a narrow trophic niche width (Levin's index, Bi < 0.6) and low overlap between species, except between barracuda and wahoo (MacArthur and Levin's, R0 = 0.72). Isotopic compositions had broad values of δ13C and δ15N, and were significantly different between species. Our results provide information about the four species' trophic organization and suggest that the predators avoid competition by preying on different prey, thus allowing their coexistence. [ABSTRACT FROM AUTHOR]

Predation from the invasive Indo‐Pacific lionfish is likely to amplify declines in marine fishes observed in multiple ocean basins. As the invasion intensifies and expands, there is an urgent need to identify species that are most at risk for extirpation—and possible extinction—from this added threat. To address this gap and inform conservation plans, we develop and apply a quantitative framework for classifying the relative vulnerability of fishes based on morphological and behavioural traits known to influence susceptibility to lionfish predation (e.g. body shape, water column position and aggregation behaviour), habitat overlap with lionfish, and degree of geographic range restriction. Applying the framework to fishes across the invaded Caribbean Sea and ahead of the invasion front in the southwestern Atlantic revealed the identity of at least 77 fishes with relatively small ranges that are likely to be most affected by lionfish predation. Trait‐based vulnerability scores significantly predict the probability of fishes appearing within the diets of lionfish across the invaded region. Spatial richness analyses reveal hotspots of vulnerable species in the Bahamas, Belize and Curaçao. Crucially, our framework identifies 29 vulnerable fishes endemic to Brazil, which has not yet been colonized by lionfish. Of these, we suggest reefs around offshore island groups occupied by a dozen highly vulnerable and range‐restricted species as priorities for intervention should lionfish spread to the region. Observations of the rate of lionfish spread across the invaded range suggest that an average of 5 years (with a median of nearly 2 years) elapses from first sighting to maximum observed densities. This lag may allow managers to mobilize plans to suppress lionfish ahead of an invasion front in priority locations. Our framework also provides a method for assessing the relative vulnerability of cryptobenthic and/or deep‐reef fishes, for which population‐monitoring data are limited. [ABSTRACT FROM AUTHOR]

Hotspots identification can be used to establish protected or priority areas for conservation at different geographic scales. We aimed to determine if San Andres, Providencia and Santa Catalina Archipelago could be considered as a hotspot of elasmobranch diversity within the Greater Caribbean. For that, we updated the elasmobranch species richness and analyze its distribution pattern, evaluated the assembly structure and composition and estimated the occurrence probability of the more abundant species of the Archipelago. A total of 46 species, 33 of sharks and 13 of batoids were recorded, with 8 categorized as threatened by IUCN. Quadrants of San Andres and Providencia islands presented the highest richness with 16 species. Oceanic environments differed significantly in composition and abundance from the other four large areas evaluated. Northern banks were the most favorable environments for large-sized pelagic sharks while San Andres and Providencia Islands were for batoids; this difference could be due to the pelagic and benthic habits, respectively, and their relation with availability of substrate, food and sheltered areas. Our study confirmed that the Archipelago has at least 21% of the total richness of the northwestern Atlantic region, 43% of that of the Greater Caribbean and 49% of that registered in the Colombian Caribbean Coast, suggesting that the Archipelago is a potential richness hotspot in the Caribbean region. This high elasmobranch diversity could be due, among others, to its status as a Biosphere Reserve, to its high diversity of habitats and more recently to the establishment of the shark fishing ban. [ABSTRACT FROM AUTHOR]