Deep-sea pelagic nekton biomass estimates in the North Atlantic: horizontal and vertical resolution of revised data from 1982 and 1983

Vertical and horizontal biomass distribution was calculated from pelagic ichthyofauna samples from hauls from 250 m to 3200 m depth in the North Atlantic. Sampling was carried out with a commercial Engel midwater trawl in 1982 and 1983 from 43°N to 59°N, and from the mid-oceanic region towards the European continental shelf. Revised pelagic biomass estimates obtained from the continental slopes off western Ireland and the Rockall Bank and from the subtropical North Atlantic were in accordance with published data, resulting in overall estimates of 25 g per 1000 m3 and 3.3–3.4 g per 1000 m3, respectively. However, over the Mid-Atlantic Ridge from 45°N to 50°N high biomass figures were found, particularly for the abyssopelagic zone (18–20.5 ± 2.8 g per 1000 m3), which are considerably higher than previously reported.