The Western Central Atlantic (WCA) hosts a population of manta rays whose distribution and habitat preference is poorly understood. Addressing this lack of knowledge will be essential to aid the effective implementation of targeted conservation measures. Here, we use ensemble ecological niche modeling to predict the monthly distribution of manta rays in the WCA using multiple sources of species occurrence data, and consequently identify core areas, which represent suitable habitat in all months of the year. Models suggest a seasonal cycle of expansion and contraction of suitable habitat from coastal areas in spring‐summer, to open ocean in autumn‐winter. Core areas are concentrated along the coast of the USA, Mexico, and Venezuela. Only 24% of predicted suitable habitat is encompassed by the present regional network of MPAs, and is intersected by numerous, heavily trafficked shipping lanes. Manta rays are slow‐growing animals that only produce a limited number of offspring; as such, this species is sensitive to even moderate increases in mortality rates. For this reason, the existing regional network of MPAs may offer them limited protection. As manta rays in the WCA are challenged by a complex landscape of threats and protective measures, future marine conservation planning in the region should explicitly address the conservation of manta rays, focusing on areas identified as key habitats for the species.
The oceanic manta ray (Mobula birostris) is a circumglobally distributed species, but little to no information exists for many parts of their range. The eastern central Atlantic Ocean is a particularly data-deficient area, where manta ray presence has seldom been reported and regional descriptions of the distribution, movement, and connectivity of populations are unavailable. This study makes use of satellite telemetry, coupled with ecological niche modeling, to provide the first description an oceanic manta ray population in the region based on observations from Cabo Verde, and describes the most likely distribution of the species in the region. Repeated surveys between 2015 and 2019 and data from 11 satellite-tracked individuals revealed a reliable and continued presence of manta rays in the archipelago, although the number of sightings was considerably lower than those reported for some of the major aggregation sites for the species and no individual was ever re-sighted. Ecological niche modeling indicates suitable habitat for manta rays exists in Cabo Verde for most of the year, though in considerably higher extent during the summer months. The model furthermore suggests possible seasonal connections between the archipelago and the wider Gulf of Guinea. The role of Cabo Verde in the life-history of oceanic manta rays in the region remains to be elucidated, though the low abundance and re-sighting frequency, coupled with modeling suggesting expanding and contracting suitable habitat, suggests that Cabo Verde might be a key stop-over along a potentially longer movement corridor.
The study presents the first national assessment of a nurse shark (Ginglymostoma cirratum) population, conducted using a combination of transect surveys and baited remote underwater videos (BRUVs). Density of nurse sharks in Belize was found to be higher in reefs than in lagoons, and in the atolls furthest away from the mainland and human settlements. Only large and old protected areas were found to have a positive impact on nurse shark abundance. Absolute abundance of nurse sharks was estimated using distance sampling analysis, giving a total nurse shark population in the range of 3,858 to 14,375 sharks. Thanks to a vast area of suitable habitat for nurse sharks in the country and legislation already in place for the safeguard of the species, Belize could represent an important hotspot for nurse sharks in the Western Atlantic. The data presented here hence offers a baseline for the long-term monitoring of the Belizean nurse shark population and improves our understanding of nurse shark abundance and distribution in the wider Caribbean basin.
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