Baited camera observations of deep-sea demersal fishes of the northeast Atlantic Ocean at 15-28°N off West Africa

For the first time the autonomous free-fall vehicle AUDOS was deployed at low latitudes in the northeast Atlantic Ocean. Observations of deep demersal fishes attracted to baited cameras were made at three stations near upwelling areas off West Africa: Canaries (27°20′N, 16°59′W), Cape Verde Terrace (17°45′N, 20°30′W), and Cape Verde Abyssal Plain (15°00′N, 20°30′W). The grenadier Coryphaenoides (Nematonurus) armatus was the main species attracted to the bait. Other fish species observed at bait were the eel Histiobranchus bathybius, a zoarcid, and the ophidiids Barathrites iris and Spectrunculus grandis. A comparison was made between this study area and the stations Porcupine Abyssal Plain (48°50′N, 16°30′W), which is eutrophic, and Madeira Abyssal Plain (31°00′N, 20°00′W), which is oligotrophic. These are situated on either side of a proposed faunal divide at 40°00′N with a high abundance of large species of rattails to the north and lower biomass of smaller fish species to the south. This study revealed a high abundance of large C. (N.) armatus at 17°00′N, which is a violation of this putative zoogeographic divide. It is suggested that high primary productivity and upwelling off West Africa sustain this assemblage of deep demersal fishes.