Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 4131
Title: Potential overlap between cetaceans and commercial groundfish fleets that operate in the California Current Large Marine Ecosystem
Author: Blake E. Feist, Marlene A. Bellman, Elizabeth A. Becker, Karin A. Forney, Michael J. Ford, P. S. Levin
Publication Year: 2015
Journal: NOAA Professional Paper
Volume: 17
Pages: 27
DOI: doi:10.7755/PP.17
Keywords: Groundfish,cetaceans,California Current,spatial analysis,commercial fishing,risk assessment
Abstract:

Cetacean populations are confronted by many anthropogenic threats, including commercial whaling, noise, vessel collisions, gear entanglement, exploitative competition, habitat disturbance, and global climate change. Evidence indicates that commercial fishing activities can have both direct (e.g., gear entanglement and bycatch) and indirect (e.g., prey reduction and noise) effects on cetaceans. However, few studies have addressed the potential vulnerability of a given cetacean species to an en- tire fishing fleet that operates over a large marine ecosystem. In this study, we overlaid spatially explicit multiyear predicted mean densities of 11 cetacean species and 1 species guild within the California Current Large Marine Ecosystem with data for commercial fishing effort of the fixed-gear, at-sea hake mid-water trawl, and bottom trawl fleets of the west coast groundfish fishery. We quantified the exposure of each species to each fleet type by multi- plying the predicted mean cetacean density by the measured fishing fleet effort. We found large interspecific and interfleet variability in the overlap between cetaceans and fishing fleets. Although many of the species had relatively low overlap rates, others had substantial exposure to some of the fishing fleets, particularly those species with more nearshore distributions. Direct mortality from these fleets has been documented to be low, but our results indicate that there is opportunity for fisher- ies interactions with some cetacean species, particularly in the fixed-gear fleet. Our analyses make up an important first step in generating for- mal risk assessments for quantifica- tion of the impacts of various fish- ing fleets on populations of cetacean species that occur in the California Current. 

Theme: Ecosystem Approach to Management for the California Current Large Marine Ecosystem
Foci: Describe the interaction between human activities and ecosystem status and resilience.
Official Citation:

Feist, Blake E., Marlene A. Bellman, Elizabeth A. Becker, Karin A. Forney, Michael J. Ford, and Phillip S. Levin. 2015. Potential overlap between cetaceans and com- mercial groundfish fleets that operate in the California Current Large Marine Eco- system. NOAA Professional Paper NMFS 17, 27 p. doi:10.7755/PP.17