Macrofauna associated with macroalgae in the Kongsfjord (Spitsbergen)

Abstract.

Macrofauna associated with six abundant macroalgal species was investigated in Kongsfjord, Spitsbergen, in order to qualitatively and quantitatively describe macroalgal epifauna composition. A total of 104 invertebrate species were identified, with bryozoans and amphipods representing the most abundant taxa. Analysis of similarity of epifaunal composition showed differences between algal species, and four groups could be distinguished: a Laminaria-Alaria group, a Ptilota-Phycodrys group, Desmarestia aculeata and Acrosiphonia aff. flagellata. Abiotic factors such as temperature and salinity were found to play a minor role in structuring epifaunal communities, while wave action and ice abrasion at least partially determine the epifauna on plants growing in the upper sublittoral. Major factors influencing composition of associated epifauna are the overall growth form and the three-dimensional thallus structure of macroalgae. None of the epifaunal species showed high host specificity. Patterns of dominating animal taxa and distribution among algal groups in Kongsfjord are similar compared to other biogeographic regions, although epifauna associated with Arctic macroalgae seems to be less rich in species.