Bathyal demersal fishes of Charlie-Gibbs Fracture Zone region (49–54°N) of the Mid-Atlantic Ridge: II. Baited camera lander observations

Nicola J Cousins,Thomas D Linley,Alan J Jamieson,Philip M Bagley,Hannah Blades,Tetrienne Box,Rosanna Chambers,Alexander Ford,Mark A Shields,Imants G Priede

doi:10.1016/j.dsr2.2013.08.002

Nicola J Cousins, Thomas D Linley + Show 8 more

Open Access

https://doi.org/10.1016/j.dsr2.2013.08.002

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Abstract

Demersal fishes appearing at baited cameras at 2500m depth either side of the axis of the Northern Mid-Atlantic Ridge (MAR) at 54°N and 49°, north and south of the Charlie Gibbs fracture Zone respectively, showed significant differences in species composition between north and south. A total of 19 taxa were observed, with Hydrolagus affinis, Bathyraja richardsoni, Halosauropsis macrochir, Histobranchus bathybius, Synaphobranchus kaupii, Coryphaenoides armatus, Corphaenoides brevibarbis, Coryphaenoides mediterraneus/leptolepis, Antimora rostrata and Spectrunculus crassa occurring at all locations. The total species assemblage comprised 40% of species captured by trawl at the same locations indicating a high proportion of scavenging species on the MAR. The most abundant was C. armatus showing shorter arrival times and larger body size in the north, suggestive of higher population density and higher food availability. The next most abundant species A. rostrata however showed faster arrival in the south but larger size in the North. No differences could be discerned between stations at the same latitude east and west of MAR axis.

Highlights

The Mid-Atlantic Ridge (MAR) is the most significant topographical feature in the North Atlantic Ocean providing extensive bathydemersal habitat in an otherwise abyssal central NorthAtlantic basin (Niedzielski et al, 2013)
There was no significant difference in species composition either side of the MAR and population densities of A. rostrata and C. armatus were similar
The current study reveals a diverse scavenging fish assemblage present on the MAR through a series of lander deployments over three sampling seasons

Summary

Introduction

Atlantic basin (Niedzielski et al, 2013). Demersal fish community composition on the MAR has been extensively explored using trawls (Bergstad et al, 2008), long lines (Fossen et al, 2008) and baited cameras (King et al, 2006) over wide latitudinal and depth ranges. Depth and latitude were consistently found to be the primary determinants of species composition at any given location (Bergstad et al, 2008, Fossen et al, 2008, King et al, 2006). The CGFZ allows water to circulate between the eastern and western North Atlantic basins (Read et al, 2010, Miller et al, 2013).

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