Structure and zonation of demersal fish assemblages off the Azores Archipelago (mid-Atlantic)

• Published in: Marine ecology. Progress series (Halstenbek) Vol. 324; pp. 241 - 260
• Main Authors: Menezes, Gui M., Sigler, Michael F., Silva, Helder M., Pinho, Mario R.
• Format: Journal Article
• Language: English
• Published: Oldendorf Inter-Research 23-10-2006
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Archipelagos; Biological and medical sciences; Fauna; Fundamental and applied biological sciences. Psychology; Lean fishes; Longline fishing; Marine; Marine ecology; Marine fishes; Pisces; Sea water; Sea water ecosystems; Seamounts; Species; Species diversity; Synecology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Azores; Atlantic Ocean Islands; ANE, Atlantic, Azores; Benthic organism; Water masses; Zonation; Azores Archipelago; Island; Demersal fish assemblages, Islands; Marine environment; Vertebrata; Animal community; Pisces; Fish distribution; Seamount; Seamounts
• ISSN: 0171-8630; 1616-1599
• DOI: 10.3354/meps324241

The assemblages of the demersal fish fauna of the Azores Archipelago are described from longline surveys that extended from the coastline to 1200 m water depth. A total of 104 fish species from 47 different families were caught, and despite the changes of biogeographic affinities with depth, most species caught are of subtropical origin (mainly from the Eastern Atlantic/Mediterranean areas) or have a broad geographic distribution. Four large-scale fish assemblages following a depth-aligned structure were found: a shallow-shelf/shelf-break assemblage at depths < 200 m, an upper-slope assemblage at 200–600 m, a mid-slope assemblage at 600–800 m and a deep mid-slope assemblage at 800–1200 m. Within the main shallow assemblage, 4 small-scale fish assemblages were found: an inner-shelf-island assemblage, an outer-shelf-island assemblage, a seamount/island-shelf/shelf-break assemblage and a transitional shelf/break assemblage. The bathymetric delineation of the mid-slope assemblages coincides with the known distributions of the North Atlantic Central Water (NACW), Mediterranean Water (MW) and the upper influence of the intermediate waters in the region: the northern sub-polar waters (Subarctic Intermediate Water [SAIW], the Labrador Sea Water [LSW]) and the Antarctic Intermediate Water (AAIW). The delineation of the shallow small-scale fish assemblages appears to be determined by small-scale environmental factors (e.g. bottom characteristics, seamounts or island areas).