Filters: Tags: sea urchins and sand dollars (X)
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The data consist of counts of sea urchins in quadrats from over 600 nearshore rocky bottom sites that were sampled by scuba between 1987 and 2021. The sites are from 38 locations on the north Pacific Rim ranging from Bering Island, along the Aleutian Island chain and the Alaska Peninsula to Southeast Alaska. At each site, divers counted and collected sea urchins from quadrats placed at random distances mostly along a 20-25-foot depth contour. At a subset of sites, 40-foot depths were targeted. Urchins were counted until either 20 quadrats were sampled or about 200 urchins were collected. Quadrat size is specified in the data table but was 0.25 m2 at almost all sites. At the same sites where urchins were counted,...
Categories: Data;
Tags: Russia,
Southeast Alaska,
Southwest Alaska,
Western Aleutian Islands,
benthic ecosystems,
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),...
Four data sets are included here to aid in assessing the influence of substrate complexity on kelp forest ecosystem stability. One data set consists of counts of a suite of kelps and benthic invertebrates on permanent band transects (swaths) at six long-term monitoring sites from 1980-2018. A second data set consists of total counts of adult California sheephead (Semicossyphus pulcher), an important sea urchin predator, on these sites from 1981-2018. The third data set gives an index of the relative substrate rugosity in the form of replicate distances along the bottom profile of each permanent swath. Finally, bottom temperatures recorded from 2015-2019 show the relatively homogenous water mass that encompasses...
The data represent counts of individuals of a suite of kelp and macroinvertebrate species on fixed 10-meter by 2-meter benthic transects on permanent subtidal monitoring sites around San Nicolas Island between 1980 and 2018. There were six sites, each of which had five 20 square meter band transects. The sites were usually monitored twice per year, most often in October and April. The species list is as follows: Stephanocystis osmundacea (formerly Cystoseira osmundacea), Laminaria spp., Eisenia arborea, Pterygophora californica, Macrocystis pyrifera greater than 1 m tall, Macrocystis pyrifera less than 1 m tall, Juvenile Laminariales (genus uncertain), Mesocentrotus franciscanus (formerly Strongylocentrotus franciscanus),...
Categories: Data;
Tags: Attached Sea Urchins,
Benthic Macroalgae,
California,
Northeast Pacific,
Pacific,
The data consist of test diameters of sea urchins collected from quadrats from over 600 nearshore rocky bottom sites that were sampled by scuba between 1987 and 2021. The sites are from 38 locations on the north Pacific Rim ranging from Bering Island, along the Aleutian Island chain and the Alaska Peninsula to Southeast Alaska. At each site, divers counted and collected sea urchins from quadrats placed at random distances mostly along a 20-25-foot depth contour. At a subset of sites, 40-foot depths were targeted. Urchins were counted until either 20 quadrats were sampled or about 200 urchins were collected. Collected urchins were measured on the surface with plastic vernier calipers. Quadrat size is specified in...
Categories: Data;
Tags: Russia,
Southeast Alaska,
Southwest Alaska,
Western Aleutian Islands,
benthic ecosystems,
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