Graduation Date
Fall 2025
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Fisheries
Committee Chair Name
Dr. Andre Buchheister
Committee Chair Affiliation
Cal Poly Humboldt Faculty or Staff
Second Committee Member Name
Dr. Jose Marin Jarrin
Second Committee Member Affiliation
Cal Poly Humboldt Faculty or Staff
Third Committee Member Name
Dr. Melissa Monk
Third Committee Member Affiliation
Community Member or Outside Professional
Fourth Committee Member Name
Dr. Timothy Mulligan
Fourth Committee Member Affiliation
Cal Poly Humboldt Faculty or Staff
Keywords
Quillback rockfish, Growth, Von Bertalanffy, Covariates, Northeast Pacific Ocean, Upwelling
Subject Categories
Fisheries
Abstract
Quillback rockfish (Sebastes maliger) are a nearshore fishery species found across the Northeast Pacific Ocean, but recent stock assessments have identified a research gap for biological growth parameters, particularly for the southern end of their range. Age-length data compiled from California to Alaska (n=34,396) was used to generate extended von Bertalanffy models with spatial, biological, and environmental covariates, specifically region, sex, depth, and an upwelling index. The objectives of this study were to explore how 1) spatial and 2) environmental covariates affect model parameters L∞, k, and t0. Four total models were developed: one model included spatial covariates of region, depth, and sex from California to southeastern Alaska; and three models included an environmental covariate of upwelling (the Biologically Effective Upwelling Transport Index, BEUTI) and sex, with one model for each coastal region that had BEUTI data available (California, Oregon, and Washington). L∞, k, and t0 estimates for all four models had varying significant relationships with covariates. Notably, among regions, L∞ estimates were larger in the southern regions (California to Washington) than the northern regions (British Columbia to southeast Alaska) and smallest for Washington Puget Sound, and k estimates tended to increase from northern to southern regions. Environmental impacts of BEUTI on growth parameter values were significant for models in the CA and OR regions, but not the WA region. In CA, the effect of BEUTI on all three model parameters was greater in magnitude to OR, however the relationship with L∞ was negative in CA and positive in OR. Sex was significant for nearly all parameters in most models, but effect sizes were generally small, suggesting there is not a large biological effect of sex on growth parameters. This study shows that spatial and environmental conditions play an important role in quillback rockfish growth and can contribute to improved stock assessments for the species.
Citation Style
APA
Recommended Citation
Stuart, Claire E., "Environmental and spatial drivers of quillback rockfish (Sebastes maliger) growth in the northeast Pacific Ocean from California to Alaska" (2025). Cal Poly Humboldt theses and projects. 2524.
https://digitalcommons.humboldt.edu/etd/2524