Date

Summer 2021

Document Type

Master's Thesis (Open Access)

Degree Name

Master of Science (M.S.)

Department

Moss Landing Marine Laboratories

Abstract

Marine fishes that persist across broad geographic ranges experience gradients in environmental and oceanographic conditions, anthropogenic stressors, and ecological factors that influence their population dynamics Understanding the spatial and temporal scale at which life history characteristics and demographic patterns vary is essential for successful management and long term sustainability of marine fisheries The Canary Rockfish is a commercially and recreationally valuable groundfish species along the West Coast of North America. After being declared overfished in 2000, several restrictions were put in place to constrain commercial and recreational fishing opportunities These restrictions coupled with favorable ocean conditions led to the recovery of the Canary Rockfish stock to a rebuilt status of 40% unfished biomass in 201 5. Despite being an important species in the management of U.S. West Coast fisheries, the life history of Canary Rockfish across untrawlable habitat s have rarely been described, including latitudinal patterns in life history traits and population demography. From 2017 through 2019, 1,567 Canary Rockfish were collected from 13 port locations along the U.S. West Coast, to investigate latitudinal patterns in size and age structure, growth, maturity, condition, and mortality, as wells as to identify biologically relevant population breakpoints along the coast. Sex specific differences in life history parameters were al so investigated coastwide. Canary Rockfish exhibited strong latitudinal patterns in life history parameters; Canary Rockfish from colder, northern port locations exhibited larger sizes at age, lived longer had variable condition, matured at larger sizes a nd older ages and had lower mortality rates than Canary Rockfish from warmer, southern port locations. Male Canary Rockfish exhibited smaller sizes at age, lived longer, were in similar condition and matured at similar sizes in comparison to female conspecifics. Trends in life history parameters related to size, age and maturity were negatively correlated with coastwide patterns in sea surface temperature a nd positively correlated with coastwide patterns in primary productivity (chlorophyll a Cluster analysis using life history traits indicated central Oregon as a biologically relevant break point for Canary Rockfish populations along the U.S. West Coast and should be considered in future stock assessment models. Further research should explore stock structure through genetic analysis and compare hook and line data from untrawlable habitats with fishery independent bottom trawl surveys to assess habitat based differences in Canary Rockfish life history and demography.

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