Few studies have described the effects of disturbance and recovery of deep-sea benthic communities. Here, we present the first study exploring recovery of a deep-sea sponge ground in the Norwegian Arctic. The effects of a single bottom trawl on two distinct benthic communities were investigated by comparing the disturbed area to nearby control areas four years after disturbance using video imagery. Overall, megafaunal (>1 cm) densities in the first trawl mark (~600 m depth) were 12.86±1.19 individuals mˉ², significantly lower than in control areas (26.6±1.27 individuals mˉ²). On the second, deeper trawl mark (~1400 m depth), the densities of megafauna were 0.26±0.02 individuals mˉ², significantly lower than control areas (0.52±0.06 individuals mˉ²). Many epibenthic taxa were significantly impacted by the trawl, including Hexactinellids, Craniella infrequens, Lissodendoryx complicata, Haliclonia sp, Stylocordyla borealis, Gersemia rubiformis, anemones, and ascidians. However, we found some species to be equally abundant between transects. We speculate that this is due to trawl survival, not recovery, since trawl effectiveness is known to vary. Multivariate analyses revealed a distinct separation between disturbed and control communities for both sites, with trawling causing 30-48% of the variation. Furthermore, in the shallower site, the disturbed area had considerably less spicule mat than control areas. Overall, our results suggest that four years is not enough for an Arctic, deep-sea sponge ground to fully recover from a trawling disturbance.
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