Between 1987 and 2021, over 600 nearshore rocky bottom sites were sampled by scuba at 38 locations on the north Pacific Rim ranging from Bering Island, along the Aleutian Island chain and the Alaska Peninsula to southeast Alaska. Sites were plotted at random from along the coasts of islands or areas designated. Hard substrate was targeted. Most sites were sampled more than once, years or decades apart. Many sites in the western Aleutians were resampled several times as sea otter populations densities changed there. Each site was sampled using 20 quadrats along 20-25-foot depth contour. At a subset of sites, 40-foot depths were sampled. Divers counted kelps but non-motile invertebrates, Desmarestia spp. (acid weed), fleshy red algae, erect coralline algae, encrusting coralline algae, and encrusting Codium were each subjectively rated on a percent cover scale of 1 - 6 where 1 is 0 percent to 5 percent, 2 is 6 percent to 25 percent, 3 is 26 percent to 50 percent, 4 is 51 percent to 75 percent, 5 is 76 percent to 95 percent, and 6 is 96 percent to 100 percent. Quadrat size was 0.25 m2 at almost all sites but is specified in the data tables. At the same sites where kelps were counted, divers counted and collected sea urchins from quadrats placed at random distances along the same depth profile. Urchins were counted and collected from quadrats until either 20 quadrats were sampled or about 200 urchins were collected. Test diameters of collected urchins were measured and recorded on the surface. Sites included here are at Adak Island, Agattu Island, Akutan Island, Alaid Island, Amchitka Island, Anangula Island, Atka Island, Attu Island, Bering Island, Chiachi Island, Chuginadak Island, Hawadax (formerly Rat) Island, Kiska Island, Kodiak Island, Mitrofania Island, Nizki Island, Ogliuga Island, Sanak Island, Seguam Island, the Semidi Islands, Shemya Island, Sitkalidak Island, Skagul Island, Tanaga Island, Umnak Island, Unalaska Island, Unga Island, Yunaska Island; Amalik Bay, Kukak Bay, and Pavlov Bay on the Alaska Peninsula; Kachemak Bay on the Kenai Peninsula; and Torch Bay, Surge Bay, and Sitka Sound in Southeast Alaska. Site locations (SiteLocs.csv), sea urchin count data (UrchinCounts.csv), sea urchin size data (UrchinSizes.csv), and kelp count and bottom cover data (AKKelpData.csv) are presented in separate tables.
