During 2016-2018, unprecedented aggregations of the colonial pelagic tunicate Pyrosoma atlanticum were observed in the Northern California Current (NCC). Pyrosomes are common in tropical and sub-tropical ocean waters, but little is known about their abundance, distribution, and trophic ecology in mid-latitude systems. To assess these factors, pyrosomes were collected during...
Aggregations of the neustonic hydrozoan Velella velella occur periodically in the northern California Current. Despite the regular occurrence of notable bloom events in this productive upwelling zone, little is known about their trophic ecology. We used gut content and stable isotope analyses (SIA) to elucidate V. velella prey selectivity and...
Pyrosomes are colonial pelagic tunicates that have fascinated marine biologists for over a century. Their name comes from the “fiery” bioluminescence that luminous organs produce at night time. Blooms of pyrosomes, identified as Pyrosoma atlanticum (Peron, 1804), have recently appeared in the North Pacific Ocean, prompting questions about environmental factors...
Cytochrome B sequence data (FASTA format) from the paper “Seasonal distribution and environmental associations among late larval and juvenile rockfish (Sebastes spp.) off Oregon and Washington: new insights based on genetics”. The data was generated from a sample of 2534 unknown, field collected late-larval and juvenile rockfishes from the Pacific...
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...
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...
Fishery management production models tend to stress only the elements directly linked to fish (i.e. fish, fish food, and fish predators). Large coastal jellyfish are major consumers of plankton in heavily fished ecosystems; yet, they are frequently not included as model components. We explore the relationship between gulf menhaden (Brevoortia...
Fishery management production models tend to stress only the elements directly linked to fish (i.e. fish, fish food, and fish predators). Large coastal jellyfish are major consumers of plankton in heavily fished ecosystems; yet, they are frequently not included as model components. We explore the relationship between gulf menhaden (Brevoortia...
Fishery management production models tend to stress only the elements directly linked to fish (i.e. fish, fish food, and fish predators). Large coastal jellyfish are major consumers of plankton in heavily fished ecosystems; yet, they are frequently not included as model components. We explore the relationship between gulf menhaden (Brevoortia...
Variable ocean conditions can greatly impact
prey assemblages and predator foraging in marine ecosystems.
Our goal was to better understand how a change in
ocean conditions influenced dietary niche overlap among
a suite of midtrophic-level predators. We examined the
diets of three fishes and one seabird off central Oregon
during...
Variable ocean conditions can greatly impact
prey assemblages and predator foraging in marine ecosystems.
Our goal was to better understand how a change in
ocean conditions influenced dietary niche overlap among
a suite of midtrophic-level predators. We examined the
diets of three fishes and one seabird off central Oregon
during...
Interannual variability in salmon (Oncorhynchus spp.) production in the northeast Pacific is understood to be driven by oceanographic variability and bottom-up processes affecting prey availability to juvenile salmon. Scyphozoan jellyfish have an important role in shaping the pathways of energy flow through pelagic food webs. While jellyfish obtain high production...
Interannual variability in salmon (Oncorhynchus spp.) production in the northeast Pacific is understood to be driven by oceanographic variability and bottom-up processes affecting prey availability to juvenile salmon. Scyphozoan jellyfish have an important role in shaping the pathways of energy flow through pelagic food webs. While jellyfish obtain high production...
Interannual variability in salmon (Oncorhynchus spp.) production in the northeast Pacific is understood to be driven by oceanographic variability and bottom-up processes affecting prey availability to juvenile salmon. Scyphozoan jellyfish have an important role in shaping the pathways of energy flow through pelagic food webs. While jellyfish obtain high production...
Interannual variability in salmon (Oncorhynchus spp.) production in the northeast Pacific is understood to be driven by oceanographic variability and bottom-up processes affecting prey availability to juvenile salmon. Scyphozoan jellyfish have an important role in shaping the pathways of energy flow through pelagic food webs. While jellyfish obtain high production...
Fishery management production models tend to stress only the elements directly linked to fish (i.e. fish, fish food, and fish predators). Large coastal jellyfish are major consumers of plankton in heavily fished ecosystems; yet, they are frequently not included as model components. We explore the relationship between gulf menhaden (Brevoortia...
The trophic habits, size and condition of yearling Chinook salmon (Oncorhynchus tshawytscha) caught early in their marine residence were examined during 19 survey years (1981–1985; 1998–2011). Juvenile salmon consumed distinct highly piscivorous diets in cold and warm ocean regimes with major differences between ocean regimes driven by changes in consumption...
Nearshore hypoxia along the coast of Oregon and Washington is a seasonal phenomenon that has generated concern among scientists studying this temperate upwelling ecosystem. These waters are affected by coastal upwelling-induced hypoxia mainly during late summer and fall, but the effects of low oxygen levels on fish and invertebrate communities,...
In late spring of 2010, the northern California Current (NCC) experienced a transition from El Niño to La Niña conditions resulting in anomalous distributions and concentrations within the ichthyoplankton community. We analyzed larval fish data collected during the four months before and after this transition and compared them to data...
The dynamic nature of biological hotspots, while well recognized, is not well understood. We hypothesize that the persistence of hotspots in the northern California Current System (CCS), despite seasonal and annual changes in the nekton community species composition, is related to associations among species and their functional redundancy. To address...
As fisheries management shifts to an ecosystem-based approach, understanding energy pathways and trophic relationships in the Northern California Current (NCC) will become increasingly important for predictive modeling and understanding ecosystem response to changing ocean conditions. In the NCC, pelagic forage fishes are a critical link between seasonal and interannual variation...
A majority of the world’s largest net-based fisheries target planktivorous forage fish that serve as a critical trophic link between the plankton and upper-level consumers such as large predatory fishes, seabirds, and marine mammals. Because the plankton production that drives forage fish also drives jellyfish production, these taxa often overlap...
This study investigated the spatial distribution of juvenile North Pacific albacore (Thunnus alalunga) in relation to local environmental variability
[i.e. sea surface temperature (SST)], and two large-scale indices of climate variability, [the Pacific Decadal Oscillation (PDO) and theMultivariate
El Nino/Southern Oscillation Index (MEI)]. Changes in local and climate variables were...
Relative to extensive research on the freshwater stages of steelhead Oncorhynchus mykiss life history, little is known about the species’ estuarine and early marine phases despite the decline of numerous populations, including several from the Columbia River. Comparisons of the distribution, diet, and growth of juvenile steelhead collected during surveys...
The feeding habits of pelagic, juvenile rockfishes (Sebastes spp.) collected off Oregon in 2002, and Oregon and Washington in 2006, were examined using stomach content and stable isotope analyses. Sampling occurred along a series of transects across the shelf between Crescent City, California (Lat. 41°54.0′), and Newport, Oregon (Lat. 44°39.0′),...
As in many regions of the world, the shelf waters of the western United States have experienced large increases and high interannual variability in jellyfish populations in recent decades. The northern California Current (NCC) is a productive upwelling zone that is home to large populations of medusae, particularly during some...
The Fukushima Daiichi power station released
several radionuclides into the Pacific following the March 2011
earthquake and tsunami. A total of 26 Pacific albacore (Thunnus
alalunga) caught off the Pacific Northwest U.S. coast between
2008 and 2012 were analyzed for ¹³⁷Cs and Fukushima-attributed
¹³⁴Cs. Both 2011 (2 of 2) and...
End-to-end models were constructed to examine and compare the trophic structure and energy flow in coastal shelf ecosystems of four US Global Ocean Ecosystem Dynamics (GLOBEC) study regions: the Northern California Current, the Central Gulf of Alaska, Georges Bank, and the Southwestern Antarctic Peninsula. High-quality data collected on system components...
Variable ocean conditions can greatly impact
prey assemblages and predator foraging in marine ecosystems.
Our goal was to better understand how a change in
ocean conditions influenced dietary niche overlap among
a suite of midtrophic-level predators. We examined the
diets of three fishes and one seabird off central Oregon
during...
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...
In the California Current coastal boundary zone, the spring transition between downwelling and upwelling conditions, along with the fluctuating structure of the Columbia River plume, creates highly dynamic interactions. In this study, we investigated whether the surface distribution of brachyuran larvae and ichthyoplankton would track the dynamics of the Columbia...
Diets of juvenile coho Oncorhynchus kisutch and Chinook O. tshawytscha salmon
are made up primarily of winter-spawning fish taxa in the late-larval and early juvenile stages that
are undersampled in plankton and larger trawl nets. Although we have no direct measure of the
availability of fish prey important to juvenile...
Predatorprey interactions are a primary structuring force vital to the resilience of marine communities and sustainability of the worlds oceans. Human influences on marine ecosystems mediate changes in species interactions. This generality is evinced by the cascading effects of overharvesting top predators on the structure and function of marine ecosystems....
The state of the California Current System (CCS)
since spring 2011 has evolved in response to dissipation
of La Niña through spring and summer, resurgence of
cooler La Niña conditions in fall and winter, and finally
a transition towards ENSO-neutral conditions in spring
2012. The resurgence of La Niña was...
Ecological interactions between natural and
hatchery juvenile salmon during their early marine
residence, a time of high mortality, have received little
attention. These interactions may negatively influence
survival and hamper the ability of natural populations to
recover. We examined the spatial distributions and size
differences of both marked (hatchery) and...
We examined variability in growth rate during the larval stage of northern anchovy (Engraulis mordax) in response to physical and biological environmental factors in 2005 and 2006. The onset of spring upwelling was anomalously delayed by 2–3 months until mid-July in 2005; in contrast, spring upwelling in 2006 began as...
We investigated habitat use by juvenile Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) to identify environmental characteristics that may define their optimal marine habitat. We utilized physical and biological data from four cruises in the northern California Current system from Newport, Oregon, to Crescent City, California, in June...
The Northern California Current (NCC) is a seasonally productive and open ecosystem. It is home to both a diverse endemic community and to seasonally transient species. Productivity and food web structure vary seasonally, interannually, and decadally due to variability in coastal upwelling, climate-scale physical processes, and the migratory species entering...
Climatic effects in the ocean at the community level are poorly described, yet accurate predictions about ecosystem responses to changing environmental conditions rely on understanding biotic responses in a food-web context to support knowledge about direct biotic responses to the physical environment. Here we conduct time-series analyses with multivariate autoregressive...
Blooms of jellyfish around the world have been correlated with climatic variables related to environmental causes. Sizeable populations of large medusae, primarily Chrysaora fuscescens and Aequorea sp., appear annually in shelf waters of the Northeast Pacific Ocean. Previous research has shown that C. fuscescens is abundant seasonally in the inner...
Dramatic changes in the physical and biological conditions off Washington and Oregon, USA, have occurred since 1998, including extreme El Niño (warm) and La Niña (cool) years, high and low Columbia River flow years, a major intrusion of subarctic water, and a low oxygen event on the shelf. The occurrence...
There has been a dramatic increase in jellyfish biomass over the eastern Bering Sea shelf since the early 1990s, which was previously hypothesized to have been triggered by changing climate and ocean conditions. We examine the hypothesis that the presence of these large carnivores has affected fisheries resources, either through...
Eastern boundary current (EBC) upwelling zones are among the most productive of marine ecosystems globally and have been generalized in terms of their food web structure. Little empirically based evidence exists to suggest that there is any one form of trophic control of EBC systems and, because of logistical constraints,...
Well-defined fronts develop at the seaward edge of riverine plumes where suspended materials and planktonic organisms are concentrated by convergent water flows. Riverine plume fronts have been hypothesized to be favorable fish habitats because they can lead to localized prey
aggregations. We examined the spatial distribution of juvenile Pacific salmonids...
The species composition, distribution and concentration of ichthyoplankton off the central Oregon coast in the NE Pacific Ocean were examined during 2000 and 2002 to investigate annual, seasonal, vertical, and cross-shelf variability. Larval concentrations were also analyzed in relation to water temperature and salinity. The 281 samples collected from 5...
The diel feeding periodicity of juvenile Chinook salmon Oncorhynchus tshawytscha was determined from stomachs collected in coastal waters off Oregon in 2000 and 2003. Juvenile Chinook salmon exhibited a diurnal feeding pattern with morning and evening feeding periods. There were differences in the duration and magnitude of the dawn and...
Successfully shifting to a more piscivorous diet may be an important factor in the growth and survival of juvenile coho salmon Oncorhynchus kisutch and Chinook salmon O. tshawytscha during their first summer in the northern California Current. Nonmetric multidimensional scaling and cluster analysis of diets by size showed several distinct...
The surface-layer zone, occupying the upper 20 cm of the water column, represents a unique oceanic environment. A diverse assemblage of organisms occupies this zone, either in an obligate or facultative manner (Zaitsev 1970, Hempel and Weikert 1972, Cheng 1975, Peres 1982). Certain animals show morphological or biochemical adaptations to...
Previously published in California Cooperative Oceanic Fisheries Investigations Progress Report, 2007, Vol.48; access courtesy of publisher and authors.
Coastal Pacific hake (Merluccius productus) are known
to spawn in the southern California Bight from January
to March, migrate north during late spring and summer
to feed off Oregon, Washington, and British Columbia,
and then move back to southern California in the fall.
Juvenile Pacific hake nursery areas have been...