Distribution and Trophic Ecology of Bathylagus euryops (Teleostei: Microstomatidae) Along the Northern Mid-Atlantic Ridge

The distribution and trophic ecology of many deepwater fishes in the North Atlantic are well documented, particularly for commercially important species. However, few studies based on large-scale latitudinal and vertical gradients have been performed. In June 2004, the MAR-ECO (Census of Marine Life) research expedition aboard the R/V G.O. Sars sampled the deep-pelagic fauna over the northern Mid-Atlantic Ridge with the objective of quantitatively assessing the nekton associated with the ridge from Iceland to the Azores. Catch data revealed Bathylagus euryops to be the biomass dominant species and ranked 3rd in total abundance. Generally considered to be a relatively stable and homogenous environment, the deep sea contains a diversity of habitats that are often related to changes in topographic features and associated hydrography. In this paper, we explore the distribution of B. euryops as a function of depth, ridge section, and hydrographic region over a mid-ocean ridge system. Furthermore, trophic analyses revealed that gelatinous zooplankton represent a significant component of the diet of B. euryops, emphasizing that ecosystem processes of the northern MAR differ from ‘typical’ open ocean patterns