This paper is a checklist of the fishes that have been documented, through both published and unpublished sources, in marine and estuarine waters, and out 200 miles, from the United States-Canadian border on the Beaufort Sea to Cabo San Lucas, Mexico. A minimum of 241 families and 1,644 species are known within this range, including both native and nonnative species. For each of these species, we include maximum size, geographic and depth ranges, whether it is native or nonnative, as well as a brief mention of any taxonomic issues.

Determining the prey composition and foraging habitats of U.S. Pacific Coast groundfishes are specified management directives that have not received much scientific attention. To address this knowledge gap, we conducted a meta-analysis of the feeding ecology of 18 commercially important species and their life stages during a recent review of Pacific Coast groundfish essential fish habitat. A Major Prey Index was developed to evaluate relative importance among 47 prey taxa. Based on this metric, unidentified teleosts, euphausiids, and brachyuran crabs were the most important prey groups. When 14 generalized prey categories were used, fishes represented the dominant taxon (mean % weight or volume = 32.3) followed by shrimps (11.5), crabs (10.0), and euphausiids (9.5). PERMANOVA results indicated that species-specific differences were the primary source of dietary variability among tested variables (life stage, functional group, taxonomic group). Pacific Coast groundfishes mainly were characterized as mesopredators with estimated trophic levels ranging from 3.4 to 4.2. Foraging habitats differed significantly among functional (benthic, demersal, pelagic) and taxonomic (elasmobranch, roundfish, rockfish, flatfish) groups. Using hierarchical agglomerative cluster analysis, we identified a significantly distinct trophic guild that consumes mainly polychaetes and hard-shelled molluscs (juvenile, juvenile–adult Dover Sole; juvenile–adult English Sole) and another that specializes on euphausiids (juvenile Pacific Hake; juvenile–adult Darkblotched Rockfish). Our findings filled substantial data gaps in the trophic ecology and habitat-based management of commercially important species and can be used to inform future reviews of Pacific Coast groundfish essential fish habitat.

The California Current Trophic Database (CCTD) was developed at NOAA Southwest Fisheries Science Center in collaboration with numerous diet data contributors. We compiled the CCTD from twenty-four data sets, representing both systematic collections and directed trophic studies. Diet composition data, including stomach and scat samples, were obtained from 105,694 individual predators among 143 taxa collected throughout the California Current Large Marine Ecosystem (CCLME) from 1967–2019. Predator taxa consist of squids (n = 5), elasmobranchs (n = 13), bony fishes (n = 118), and marine mammals (n = 7). Extensive time series are available for some predators (e.g., California Sea Lion, Pacific Hake, Chinook Salmon). The CCTD represents the largest compilation of raw trophic data within the CCLME, allowing for more refined analyses and modeling studies within this region. Our intention is to further augment and periodically update the dataset as additional historical or contemporary data become available to increase its utility and impact.

The yellowtail rockfish, Sebastes flavidus, is a widespread and abundant mesopredator in the California Current Large Marine Ecosystem. We utilized stomach content and stable isotope analyses to investigate the trophic ecology of this species at three sites off central California just before (August–October 2013) and during (August and October 2014) a marine heat wave. Sebastes flavidus largely consumed pelagic prey (zooplankton and micronekton). Diets were dominated by tunicates (salps and pyrosomes), pelagic crustaceans (euphausiids, hyperid amphipods, larval decapods), and fishes, with the relative contribution of these prey taxa varying spatially (sample location, longitude, depth) and temporally (year, month), based on complementary multivariate analyses. Prey-specific indices demonstrated that individual S. flavidus diet composition typically was dominated by one of these prey groups, and that prey switching occurred based on the relative availability of prey and their energetic importance. Stable isotope analysis of δ¹⁵N indicated that the S. flavidus populations sampled in 2014 had been feeding at an elevated trophic position and more variable prey spectrum relative to 2013, probably as a consequence of greater piscivory and the incorporation of temporal changes in diet composition. Because its opportunistic feeding behavior reflects the dynamism and heterogeneity of the pelagic forage preyscape, S. flavidus may be an important ecosystem indicator species. For example, the novel incorporation of pyrosomes as a large portion of the diet of S. flavidus during 2013–2014 directly related to the massive increase in pyrosome abundance in the California Current during the 2014 marine heat wave.

Quantifying trophic relationships of marine species is fundamental to the construction and performance of ecosystem models, development of effective ecosystem-based fisheries management strategies, and support of trait-based approaches to ecological risk assessment. Accounting for food web dynamics in taxonomically diverse ecosystems, such as the California Current Large Marine Ecosystem (CCLME), is especially challenging because of the sheer number of trophic linkages and their inherent variability. Consequently, analyses that can inform the most appropriate means of aggregating species or other taxonomic groups into assemblages or guilds are critical to reducing system complexity for modeling and management, particularly when data are limited. To provide a methodological approach that is globally applicable in such cases, we define trophic guilds within biogeographic regions of the CCLME, compare results among these regions, and discuss ecological and management implications. Within each biogeographic region, predator guilds were clearly demarcated by foraging habitat (benthic, nearshore pelagic, offshore pelagic), scale of foraging movements, and trophic position. Furthermore, trophic guilds were distinctive for each region, with species composition and the noted ecological characteristics largely driving guild structure. Predator species that are reliant on continental slope and offshore foraging habitat, such as adult Pacific Hake, have diets that are representative of these areas and are similar throughout the CCLME. Generally, larger, more mobile predators that typically feed in deeper offshore waters, including swordfish, sea lions, and sharks clustered together in multiple bioregions along the coast; all reliant primarily on fishes and squids. Throughout bioregions, groundfishes preyed on benthic invertebrates (e.g., decapods, amphipods, polychaetes), while shelf-oriented pelagic predators, including smaller salmon, preyed on pelagic invertebrates (e.g., euphausiids, copepods, gelatinous zooplankton). A large number of forage taxa that are well represented in this study have dynamics largely dependent on oceanographic conditions at a regional scale (e.g., decapods), basin scale (e.g., copepods), or a combination of both (e.g., euphausiids, Northern Anchovy). Such distinctions indicate that spatial and temporal scales of coherence of predators and prey also must be considered in development of ecosystem models and evaluation of management strategies. Our study quantifies the spatial coherence of predator guilds integrated over decades within and across bioregions of the CCLME, providing an improved understanding of regional ecosystem functioning. The analytical approach we developed may be easily extended to address similar ecological and ecosystem based fisheries management priorities in other marine regions.