Holdfast associated epifauna in Hornsund fjord kelp forest.

Citation: Ronowicz Marta, Legeżyńska Joanna, Kukliński Piotr, Włodarska-Kowalczuk Maria (2025) Holdfast associated epifauna in Hornsund fjord kelp forest. [dataset] IOPAN geonetwork

Material was collected by SCUBA divers at three sites in Hornsund fjord (Isbjørnhamna - Gla1, Hyrneodden – Gla2, and Hofferpynten - NoGla) located at different distances from glacier outflows in July 2003. At each site, the three most common kelp species (Laminaria digitata – L.dig, Saccharina latissima – S.lat, and Alaria esculenta – A.esc), together with their associated fauna, were sampled at depths of 5 and 10 m. Algae were cut from the substratum, placed in bags, and fixed in 4% buffered formaldehyde (265 algal specimens in total). Kelp age was estimated by counting annual growth rings in thin transverse sections of the stipe taken just above the holdfast, following the method described by Kain (1963) for Laminaria hyperborea. Macrobenthic fauna associated with kelp holdfasts were identified to the lowest possible taxonomic level. Both mobile and sessile organisms were counted. Mobile fauna (e.g. crustaceans) may have been underestimated, as some individuals could have escaped during sample collection despite careful handling. Hydrozoans were counted as single individuals when the number of colonies could not be determined precisely; therefore, their abundance may also be biased and underestimated.

Three sites:
Gla1 - Isbjørnhamna (76.995354 N, 15.552810 E)
Gla2 - Hyrneodden (77.024350 N, 16.047185 E)
NoGla - Hofferpynten (76.947155 N, 15.765279 E)