Differences in demersal fish biodiversity, abundance and biomass around the MAR have previously been explored in terms of depth and latitudinal... » More

Differences in demersal fish biodiversity, abundance and biomass around the MAR have previously been explored in terms of depth and latitudinal gradients, however, this is the first study to examine demersal fish distributions at a restricted depth range in the bathyal zone at different locations on the MAR. As a result of sampling difficulties comparatively little work has been carried out on the Mid-Atlantic Ridge (MAR) compared to other regions in the North East Atlantic. Demersal fish trawl data was collected on two ECOMAR cruises onboard the RRS James Cook (2007, 2009). The trawls were conducted at three sites on the MAR allowing comparisons of the demersal fish communities north and south of the Charlie-Gibbs Fracture Zone and across the ridge east to west. All trawls were conducted at a restricted depth of 2500 m. Results from the MAR are compared to published data for the Porcupine Seabight, to investigate distribution differences between the continental slopes and the relatively isolated MAR. Differences in biodiversity, abundance and biomass of individual species were identified between sites on the ridge and between the MAR and the PSB indicating that there are differences in the distribution of species, and hence community structure, between sites.

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