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The Effect of Sea Otter Predation and Habitat Structure on Nearshore Crab Assemblages in Southeast Alaska.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	The Effect of Sea Otter Predation and Habitat Structure on Nearshore Crab Assemblages in Southeast Alaska./
作者:	Cates, Rebecca Jeanette.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2022,
面頁冊數:	77 p.
附註:	Source: Masters Abstracts International, Volume: 83-10.
Contained By:	Masters Abstracts International83-10.
標題:	Ecology. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29061723
ISBN:	9798426816756

The Effect of Sea Otter Predation and Habitat Structure on Nearshore Crab Assemblages in Southeast Alaska.
Cates, Rebecca Jeanette.

The Effect of Sea Otter Predation and Habitat Structure on Nearshore Crab Assemblages in Southeast Alaska. - Ann Arbor : ProQuest Dissertations & Theses, 2022 - 77 p.

Source: Masters Abstracts International, Volume: 83-10.

Thesis (M.S.)--University of Alaska Fairbanks, 2022.

This item must not be sold to any third party vendors.

Sea otter Enhydra lutris predation has resulted in conflict with humans for shared marine resources, as sea otters reduce the abundance and size of nearshore crabs. Several species of crab in Southeast Alaska are prey for sea otters including Cancer magister, a highly valued commercial and subsistence species, as well as Cancer gracilis, Cancer productus, and Telmessus cheiragonus, species that are abundant in the nearshore and of ecological and subsistence importance. Understanding the influence of sea otters and habitat structure on valuable crab species is of particular importance in Southeast Alaska as the abundance and range of sea otters expands across important crab nursery habitat. We 1) conducted breakpoint analyses to identify sea otter density thresholds that affect the abundance and biomass of nearshore crab species, 2) used a two-factor type III Analysis of Variance (ANOVA) to test the impact of sea otter presence and year on crab size, and 3) used general linearized models (GLM) to test the impacts of sea otter density and habitat structure on crab species abundance and size distribution. We found evidence of sea otters decreasing crab species' abundance, biomass, and size. C. magister, C. gracilis, and C. productus experienced a significant decline in size in the presence of sea otters, while T. cheiragonus size did not differ as a function of sea otter presence. We found a significant decrease in biomass in C. magister and in biomass and abundance in C. productus, associated with increasing sea otter density. Different responses across crab species are likely attributed to size distributions and sea otter foraging behavior. Habitat characteristics, such as eelgrass biomass and shoot density, had a small influence on crab abundance and size that depended on the species of crab. These results suggest that populations of large crabs do not persist in the presence of sea otters, small crabs may co-occur with sea otters, and eelgrass biomass and density marginally influence crab abundance and size.

ISBN: 9798426816756Subjects--Topical Terms:

516476
Ecology.
Subjects--Index Terms:

Dungeness crab

The Effect of Sea Otter Predation and Habitat Structure on Nearshore Crab Assemblages in Southeast Alaska.
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500 $a Source: Masters Abstracts International, Volume: 83-10.
500 $a Advisor: Eckert, Ginny L.
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520 $a Sea otter Enhydra lutris predation has resulted in conflict with humans for shared marine resources, as sea otters reduce the abundance and size of nearshore crabs. Several species of crab in Southeast Alaska are prey for sea otters including Cancer magister, a highly valued commercial and subsistence species, as well as Cancer gracilis, Cancer productus, and Telmessus cheiragonus, species that are abundant in the nearshore and of ecological and subsistence importance. Understanding the influence of sea otters and habitat structure on valuable crab species is of particular importance in Southeast Alaska as the abundance and range of sea otters expands across important crab nursery habitat. We 1) conducted breakpoint analyses to identify sea otter density thresholds that affect the abundance and biomass of nearshore crab species, 2) used a two-factor type III Analysis of Variance (ANOVA) to test the impact of sea otter presence and year on crab size, and 3) used general linearized models (GLM) to test the impacts of sea otter density and habitat structure on crab species abundance and size distribution. We found evidence of sea otters decreasing crab species' abundance, biomass, and size. C. magister, C. gracilis, and C. productus experienced a significant decline in size in the presence of sea otters, while T. cheiragonus size did not differ as a function of sea otter presence. We found a significant decrease in biomass in C. magister and in biomass and abundance in C. productus, associated with increasing sea otter density. Different responses across crab species are likely attributed to size distributions and sea otter foraging behavior. Habitat characteristics, such as eelgrass biomass and shoot density, had a small influence on crab abundance and size that depended on the species of crab. These results suggest that populations of large crabs do not persist in the presence of sea otters, small crabs may co-occur with sea otters, and eelgrass biomass and density marginally influence crab abundance and size.
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653 $a Dungeness crab
653 $a Enhydra lutris
653 $a Fisheries management
653 $a Predation
653 $a Red Rock Crab
653 $a Species recovery
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