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Kelp and sea urchin data obtained by SCUBA at shallow nearshore sites along the North Pacific Rim from Bering Island to Southeast Alaska obtained over multiple decades beginning in 1987

Metadata Updated: October 2, 2025

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.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources

Dates

Metadata Created Date September 14, 2025
Metadata Updated Date October 2, 2025

Metadata Source

Harvested from DOI USGS DCAT-US

Additional Metadata

Resource Type Dataset
Metadata Created Date September 14, 2025
Metadata Updated Date October 2, 2025
Publisher U.S. Geological Survey
Maintainer
Identifier http://datainventory.doi.gov/id/dataset/usgs-6573948fd34e952b227443cf
Data Last Modified 2023-12-14T00:00:00Z
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://ddi.doi.gov/usgs-data.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id 8e960b68-bb69-4ebc-8ac8-4988d2ea4b41
Harvest Source Id 2b80d118-ab3a-48ba-bd93-996bbacefac2
Harvest Source Title DOI USGS DCAT-US
Metadata Type geospatial
Old Spatial 179.5000, 51.4000, -135.2000, 59.8000
Source Datajson Identifier True
Source Hash f6b3c29701eb695b5caf012ce0d262c4ef45e60dcaca627919e869acc9228130
Source Schema Version 1.1
Spatial {"type": "Polygon", "coordinates": 179.5000, 51.4000, 179.5000, 59.8000, -135.2000, 59.8000, -135.2000, 51.4000, 179.5000, 51.4000}

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