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Elucidating connections between ocean climate variability and change and recruitment of juvenile fishes to adult populations is critical for understanding variability in stock-recruit dynamics. Recruitment to adult rockfish populations in the California Current Ecosystem (CCE) is highly variable, leading to short- and long-term changes in abundance, productivity, forage availability, and potential fisheries yield. We used regional ocean model output, oceanographic data, and a 34- year time series of pelagic juvenile rockfish to investigate the interaction between changes in CCE source waters, as reflected by physical water mass properties, and recruitment variability. Specifically, variability of 'spiciness' on upper water isopycnals explains a substantial fraction of the variation in pelagic juvenile rockfish abundance. High rockfish abundances correspond to cooler, fresher waters with higher dissolved oxygen (i.e., 'minty') conditions, indicative of Pacific subarctic water. By contrast, years of low rockfish abundance are associated with warmer, more saline, and more oxygen-deficient (i.e., 'spicy') conditions, reflecting waters of subtropical or equatorial origin. Transport and source waters in the CCE are key factors determining density independent processes and subsequent recruitment to adult populations. L'elucidation des connexions entre la variability et les modifications du climat oceanique et le recrutement de poissons juveniles dans les populations d'adultes est essentielle a la comprehension de la variabilite de la dynamique recrues- stock. Le recrutement dans les populations de sebastes adultes dans l'ecosysteme du courant de Californie (CCE) est tres variable, entrainant des changements a court et long terme de l'abondance, de la productivite, de la disponibilite de nourriture et du rendement potentiel des peches. Nous avons utilise les sorties d'un modele oceanique regional, des donnees oceanographiques et une serie chronologique de 34 annees sur les sebastes juveniles pelagiques pour etudier l'interaction entre les variations des eaux a la source du CCE refletees dans les proprietes physiques de la masse d'eau et la variabilite du recrutement. Plus precisement, l'effet de la variabilite de la salinite et de la temperature sur les isopycnes superieurs de l'eau explique une fraction substantielle des variations de l'abondance des sebastes juveniles pelagiques. De fortes abondances de sebastes correspondent a des eaux plus douces et froides a plus forte teneur en oxygene dissous indiquant de l'eau subarctique de l'ocean Pacifique. En revanche, les annees de faible abondance des sebastes sont associees a des conditions plus chaudes, salines et pauvres en oxygene, qui refletent des eaux d'origine subtropicale ou equatoriale. Le transport et les sources des eaux dans le CCE sont des facteurs determinants de processus independants de la densite et du recrutement subsequent dans les populations d'adultes. [Traduit par la Redaction], Introduction Contemporary fisheries management is based on the need to balance fisheries removals with the need to maintain reproductive potential among exploited populations. Typically, this leads to management objectives that [...]

This report reviews the state of the California Current System (CCS) between winter 2012 and spring 2013, and includes observations from Washington State to Baja California. During 2012, large-scale climate modes indicated the CCS remained in a cool, productive phase present since 2007. The upwelling season was delayed north of 42°N, but regions to the south, especially 33° to 36°N, experienced average to above average upwelling that persisted throughout the summer. Contrary to the indication of high production suggested by the climate indices, chlorophyll observed from surveys and remote sensing was below average along much of the coast. As well, some members of the forage assemblages along the coast experienced low abundances in 2012 surveys. Specifically, the concentrations of all lifestages observed directly or from egg densities of Pacific sardine, Sardinops sagax, and northern anchovy, Engraulis mordax, were less than previous years’ survey estimates. However, 2013 surveys and observations indicate an increase in abundance of northern anchovy. During winter 2011/2012, the increased presence of northern copepod species off northern California was consistent with stronger southward transport. Krill and small-fraction zooplankton abundances, where examined, were generally above average. North of 42°N, salps returned to typical abundances in 2012 after greater observed concentrations in 2010 and 2011. In contrast, salp abundance off central and southern California increased after a period of southward transport during winter 2011/2012. Reproductive success of piscivorous Brandt’s cormorant, Phalacrocorax penicillatus, was reduced while planktivorous Cassin’s auklet, Ptychoramphus aleuticus was elevated. Differences between the productivity of these two seabirds may be related to the available forage assemblage observed in the surveys. California sea lion pups from San Miguel Island were undernourished resulting in a pup mortality event perhaps in response to changes in forage availability. Limited biological data were available for spring 2013, but strong winter upwelling coastwide indicated an early spring transition, with the strong upwelling persisting into early summer.

Environmental DNA (eDNA) metabarcoding is a new approach for assessing marine biodiversity that may overcome challenges of traditional monitoring and complement both existing surveys and biodiversity assessments. There are limited eDNA studies that evaluate vertebrate biodiversity in the marine environment or compare patterns of biodiversity with traditional methods. This study uses eDNA metabarcoding of the mitochondrial 12S rRNA genes present in seawater samples to characterize vertebrate biodiversity and distribution within National Marine Sanctuaries located in the California Current upwelling ecosystem. The epipelagic community in the study region has been monitored using traditional (mid-water trawl and marine mammal) survey methods since 1983. During 2016 and 2017, we concurrently sampled the epipelagic community using traditional survey methods and water for eDNA analysis to assess agreement among the methods. We collected replicate eDNA samples from 25 stations at depths of 10, 40, and 80 m, resulting in 131 small volume (1 L) environmental water samples to examine eDNA sequences. Across the eDNA and traditional survey methods, 80 taxa were identified. Taxa identified by eDNA partially overlapped with taxa through trawl and marine mammal surveys, but more taxa were identified by eDNA. Diversity and distribution patterns of marine vertebrates inferred from eDNA sequences reflected known spatial distribution patterns in species occurrence and community structure (e.g., cross-shelf and alongshore patterns). During both years, we identified fishery taxa Sebastes (rockfish), Merluccius (hake), Citharichthys (sanddab), and Engraulis (anchovy) across the majority of the stations using eDNA metabarcoding. The marine vertebrate assemblage identified by eDNA in 2016 was statistically different from the 2017 assemblage and more marine mammals were identified in 2017 than in 2016. Differences in assemblages identified by eDNA were coincident with different oceanographic conditions (e.g., upwelling and stratification). In 2016, weak upwelling and warmer than average conditions were measured, and vertebrate assemblages were not different among ecological regions [Point Reyes, Pescadero, and Monterey Bay]. While in 2017, average upwelling conditions returned, vertebrate assemblages differed at each region. This study illustrates that eDNA provides a new baseline for vertebrate assessments that can both augment traditional biomonitoring surveys and aid our understanding of changes in biodiversity.