Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 9039
Title: Urbanization-related distribution patterns and habitat-use by giant Pacific octopus (Entroctopus dofleini)
Author: Eliza Heery, Amy Y. Green, Blake E. Feist, Kenneth P. Sebens
Publication Year: In press
Journal: Urban Ecosystems
DOI: 10.1007/s11252-018-0742-1

Urbanization is a process that heavily alters marine and terrestrial environments, though terrestrial urban ecosystems have been studied far more intensively. Terrestrial studies suggest that urbanization can facilitate mesopredators by enhancing food and shelter resources and reducing predation pressure from apex consumers. This in turn has considerable consequences for ecological communities. We evaluated spatial distribution patterns and habitat-use of the marine mesopredator, giant Pacific octopus (Enteroctopus dofleini), relative to terrestrial urbanization intensity in Puget Sound, Washington, USA. Using field surveys and citizen-contributed data for E. dofleini, we examined whether: (1) Distribution was related to urbanization, (2) Abundance was related to the extent of benthic anthropogenic debris, and (3) Diet differed as a function of urbanization and den cover. Our results suggest that urbanization impacts may differ with depth. Mixed-effects logistic regression model estimates for the probability of occurrence increased with urbanization in deep-water (> 24 m), and decreased with urbanization in shallow water (< 18 m). Accompanying field surveys indicated that E. dofleini abundance was correlated with the number of benthic anthropogenic debris items, and that E. dofleini diets were not affected by urbanization intensity or den cover. Though E. dofleini may be synanthropic within certain urban environments, the mechanisms driving this pattern likely differ from those affecting common urban mesopredators on land, with den provisioning from man-made structures being more important than altered food resources.

Theme: Habitats to Support Sustainable Fisheries and Recovered Populations
Foci: Characterize the interaction of human use and habitat distribution, quantity and quality.
Characterize relationships between habitat and ecosystem processes, climate variation, and the viability of organisms.