Graduation Date
Summer 2019
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Fisheries
Committee Chair Name
Dr. Mark Henderson
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Dr. Andre Buchheister
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Dr. Sean Craig
Third Committee Member Affiliation
HSU Faculty or Staff
Subject Categories
Fisheries
Abstract
Oyster aquaculture has had a commercial presence in Humboldt Bay for nearly 60 years and has experienced changes in scope and methodology as the industry has grown. The traditional method of bottom-culture oyster beds has been phased out, with longline oyster aquaculture becoming the common replacement. However, this transition has preceded much of the research regarding potential impacts to the broader ecosystem. The benthic invertebrate community of Humboldt Bay is a vital food source for many commercially important fishes, as well as for the many shorebirds that utilize Humboldt Bay. The importance of the invertebrate community to the ecosystem highlights the need to investigate how off-bottom culture affects invertebrate community composition. During the summer of 2017 and the winter of 2017/18, I collected benthic and epibenthic invertebrate samples from Humboldt Bay’s North Bay. I then used multivariate analyses to compare the invertebrate community composition between eelgrass and mudflat habitats with and without aquaculture. I found that invertebrate communities responded most to the presence of structure and were not significantly different between aquaculture and eelgrass habitats. Transects conducted to measure eelgrass cover revealed significantly lower eelgrass coverage and shoot count when aquaculture was present. Eelgrass beds are important refuge areas for many juvenile fish species, as well as a vital food source for many migrating water birds. This study found that the benthic invertebrate communities were comparable between aquaculture and eelgrass habitats but that eelgrass densities were reduced in aquaculture habitats, which should be considered when managing current and future oyster aquaculture in Humboldt Bay.
Citation Style
TAFS
Recommended Citation
Coe, Hannah C., "Effects of longline oyster aquaculture on benthic invertebrate communities in Humboldt Bay, California" (2019). Cal Poly Humboldt theses and projects. 301.
https://digitalcommons.humboldt.edu/etd/301