Epibenthic megafauna associated with sponge grounds formed by the unique glass sponge Vazella pourtalesii in Emerald Basin, Nova Scotia, Canada

Abstract

Large, dense aggregations of sponges or “sponge grounds” have seen a surge of scientific interest in recent years. The pivotal ecological functions of sponges may warrant conservation measures that have been neglected in the past. The slow growth and low recovery potential of some deep-sea sponges, combined with their fragile morphologies, contributes to vulnerability to mobile fishing gear, particularly bottom trawling. The largest monospecific aggregation of Vazella pourtalesii, the Russian hat, was recently described off the Scotian Shelf between 75-275 m depth, extending over 8,500 km2 . Here I describe and compare the epibenthic megafauna inside and outside sponge grounds, and, if the condition (live, dead and damaged) of Vazella pourtalesii has an effect on the local biota and its composition. Building on previous work, I also account for the effect of substrate to see if Vazella pourtalesii enhances local biota, as previous work has shown. The results suggested that Vazella pourtalesii had a positive influence on local epibenthic megafauna, as well as the community compositions; however, more data is needed to provide a complete answer. This research will aid managers in the future, by helping to untangle the intricacies of this interesting habitat so as to avoid further significant adverse impacts.