Browsing by Author "Aguilar, Ricardo"
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- Identifying habitats of conservation priority in the São Vicente submarine Canyon in Southwestern PortugalPublication . Nestorowicz, Iga-Maria; Oliveira, Frederico; Monteiro, Pedro; Bentes, Luis; Sales Henriques, Nuno; Aguilar, Ricardo; Horta E Costa, Barbara; Gonçalves, Jorge Manuel SantosIdentifying vulnerable marine habitats is fundamental to promote evidence-based management and a sustainable use of our oceans. Although progress in the mapping of marine benthic habitats has been made, complex ecosystems such as submarine canyons remain largely unexplored, hampering evidence-based management from taking place in these ubiquitous features worldwide. Data from a remotely operated vehicle (ROV) survey in the upper São Vicente Submarine Canyon in southwestern Portugal from 2011, was analysed to carry out a comprehensive assessment of megabenthic habitats, particularly those of conservation concern occuring between 90 and 560 m. Underwater videos from three exploratory dives, covering a total of 8.8 kilometers, were analyzed through multivariate and visual assessments, and the identified habitats were assessed against a set of criteria derived from current definitions of priority habitats. Thirteen potential priority habitats were characterized, out of which four distinct “coral gardens” and one “deep-sea sponge aggregation” are aligned with OSPAR definitions of priority habitats, and one corresponds to the habitat of a strictly protected sea urchin listed in the Habitats Directive. Three circalittoral sponge aggregations were also suggested based on the abundance of indicator species. The specific composition and diversity of priority habitats as described here, has not yet been described in any other canyon in the NE Atlantic region. Depth was revealed to be particularly important for the distribution of habitats, followed by relief and substratum. The approach presented in this study contributes to improve the understanding about submarine canyons, which is paramount to implement knowledge-based protection measures. Furthermore, it can be used to support future mapping efforts of deep-sea environments such as submarine canyons.
- Marine litter in the upper São Vicente submarine canyon (SW Portugal): abundance, distribution, composition and fauna interactionsPublication . Oliveira, Frederico; Monteiro, Pedro; Bentes, Luis; Sales Henriques, Nuno; Aguilar, Ricardo; Gonçalves, J. M. S.Marine litter has become a worldwide environmental problem, tainting all ocean habitats. The abundance, distribution and composition of litter and its interactions with fauna were evaluated in the upper S. Vicente canyon using video images from 3 remote operated vehicle exploratory dives. Litter was present in all dives and the abundance was as high as 3.31 items100m(-1). Mean abundance of litter over rock bottom was higher than on soft substrate. Mean litter abundance was slightly higher than reported for other canyons on the Portuguese margin, but lower in comparison to more urbanized coastal areas of the world. Lost fishing gear was the prevalent type of litter, indicating that the majority of litter originates from maritime sources, mainly fishing activity. Physical contact with sessile fauna and entanglement of specimens were the major impacts of lost fishing gear. Based on the importance of this region for the local fishermen, litter abundance is expected to increase.