Frontiers in Marine Science (Nov 2015)
Deepwater ichthyofauna communities of two seamounts from the eastern Atlantic Ocean: results from exploratory surveys
Abstract
Deepwater fish communities were sampled during exploratory surveys on two seamounts of the north- and central eastern part of the Atlantic Ocean. Demersal fishes from Ampère Seamount, located between Madeira and the Portuguese mainland, were sampled during the P384 cruise of R.V. Poseidon in May 2009 and the M83/2 cruise of R.V. Meteor in November/December 2010, covering water depths from 60 to 4,400 m. A total of 239 fishes were collected; three chondrichthyan species and 31 teleosts in 21 families were identified. The assemblages showed a vertical zonation with little overlap, but indications for an affinity of species to certain water masses were only vague. Although most of the species present new records for Ampère Seamount, all of them have been known for the NE Atlantic and endemic species were not found. Senghor Seamount is an important fishing ground around the Cape Verde archipelago in the central eastern Atlantic. During the cruises M79/3 of R.V. Meteor in September/October 2009 and P423 of R.V. Poseidon in December 2011, a total of 106 deep-sea fishes of 28 species belonging to 18 families were caught on the seamount summit, along the slopes and on the adjacent abyssal plane. We accounted 6 new records for the Cape Verde deep-sea fish fauna. Most species have been known from other areas of the Atlantic Ocean, but these findings are an important contribution to our understanding of the distribution of deepwater fish species. The co-occurrence of northern and southern fish species at Senghor Seamount, or the Cape Verde area in general, can be attributed to the large-scale hydrographic regime with two water masses merging at the Cape Verde Frontal Zone, the North Atlantic Central Water and the South Atlantic Central Water. In general, differences between the adjacent abyssal plain and seamount slopes and summit point to the role of substrate type and habitat complexity in shaping community composition. Additionally, similarities between the fish fauna associated to other Atlantic seamounts supports the hypothesized key role of these physiographic features for species dispersion.
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