Epibenthic community biomass in Aleutian Island kelp forests, June 2016 and July 2017 (Kelp Forest Ecosystem Engineer Loss project) (NCEI Accession 0277339)

Acquisition Description:
Sampling locations were from the Aleutian Archipelago nearshore between longitude 173.9 and -167.6 in June 2016 and July 2017. The average depth 17.5 ft.

To assess community structure at each site, two methods were used. First, to quantify the remainder of the epibenthic community, ten 0.25 m2 quadrats were haphazardly placed within each site. Within these quadrats, the percent bottom cover was visually estimated for bare substrate, kelp holdfasts, suspension feeders, pulvinate green algae (Codium spp.), and non-geniculate coralline algae - with differentiation made between Clathromorphum spp. and other encrusting coralline species.

Following visual estimation, all epibenthic organisms—excepting those strongly adhered to the substrate (e.g., barnacles, non-geniculate coralline algae, etc.)— were scraped from the substrate and placed in fine mesh collection bags for shipboard identification, and abundance and biomass determination. Second, three 10 m x 2 m swaths were placed haphazardly within each site. Within each swath, E. fistulosa stipes were counted, midwater and demersal fishes visually quantified by trained divers, and Also, all conspicuous, sparsely distributed large mobile invertebrates (i.e., sea stars, crab, and large gastropods with distributions assumed to be less than 1 per 2.5 m2, the total area covered by the above quadrats) were collected in fine mesh bags for shipboard abundance and biomass determination. Once onboard, organisms were identified to the lowest possible taxa, counted (if the species occur as discrete individuals) and weighed using hanging spring scales to determine biomass to the nearest .005 kg. Ambiguous or difficult to identify individuals were preserved in 10% formalin (for invertebrates) or pressed (for algae) for later identification.