Climate Impacts on West Coast Fisheries and Protected Species
We investigate the effects of climate on fisheries and protected species in the California Current to understand their ecology better and inform management.
Who We Are
Climate change is a significant and persistent change in an area's average environmental conditions over time. In contrast, we define climate variability as shorter-term seasonal variations (e.g., changes in the direction and strength of winds) and multi-year cycles (e.g., El Niño) in environmental conditions.
Climate variability drives fluctuations in oceanographic processes like current strength and direction, water temperature, mixed-layer depth, and upwelling. These oceanographic conditions then influence the growth, distribution, and survival of various marine species. As the long-term climate changes, we expect the impact of climate variability on marine life to increase as well.
The Integrated Marine and Nearshore Ecology Team (IMNSE) uses various techniques to examine the effects of climate variation and change on West Coast fisheries and protected species like groundfish and salmon. We then connect our findings to the management of fisheries and protected species through advice to the Pacific Fisheries Management Council and NOAA West Coast Regional Office, integrating environmental indicators into stock assessments, information for recovery plans, and management strategy evaluations.
We focus on:
- Climate effects on recruitment
- Species distribution models and climate
- Harmful algal blooms
- Ecosystem considerations for stock assessments
We also contribute to:
Climate effects on recruitment
Recruitment (the number of new individuals entering a population in a particular year) is fundamental to marine species' population dynamics. Recruitment varies over space and time. Strong year classes have lasting effects on both a population’s age structure and abundance.
The youngest age groups of most marine species develop in the open water (the “pelagic phase”). As a result, changes in oceanographic features like current strength and direction, water temperature, and upwelling can have substantial impacts on the distribution, growth, and survival of young-of-year and the resulting recruitment. Understanding how climate and oceanography influence recruitment is essential for better understanding a species' ecology and management.
We use various approaches to investigate climate and oceanographic drivers’ effects on fish recruitment in the California Current Ecosystem.
Basin-scale climate indicators
Basin-scale climate and oceanographic indicators integrate climate and oceanographic conditions at large scales. They generally serve as proxies for a range of other more specific ocean conditions. For example, sea-surface height along the West Coast correlates with the direction and strength of ocean currents and the availability of northern zooplankton. The Pacific Decadal Oscillation is related to primary productivity and other climate and oceanographic features at decadal scales.
Bocaccio (Sebastes paucispinis)
Previous work examined the role of basin-scale climate variability (e.g., Pacific Decadal Oscillation, Northern Oscillation Index, El Niño, Upwelling) and density dependence on recruitment variation in bocaccio Sebastes paucispinis. A complex interaction between climate and density dependence (competition) explained 68% variability in bocaccio recruitment. Recruitment was higher in cooler, more productive years. Density dependence was also weaker in these years. This work also indicated that the historical decline in bocaccio stocks was likely due to overfishing and not climate regime shifts (Tolimieri & Levin 2005, Zabel et al. 2011).
Sablefish recruitment and sea-surface height (SSH)
We use sea-surface height (SSH) as a proxy for several oceanographic processes, including the direction and strength of ocean currents and the availability of northern zooplankton (a high-quality food item for many species). We have examined SSH as a predictor of recruitment of sablefish Anoplopoma fimbria in the California Current Ecosystem and the Gulf of Alaska.
Researchers have included SSH in some previous stock assessments (Schirripa & Colbert 2006, Schirripa et al. 2009, Connolly et al. 2014). Sablefish recruitment was negatively correlated with SSH north of North Spit, OR (approximately north of Cape Blanco). Lower SSH correlates with stronger upwelling and southerly transport in surface waters, suggesting higher productivity and northern zooplankton availability. Lower SSH in the north also correlates with the stronger poleward flow in deep waters. We included an environmental recruitment index based on SSH in the 2019 sablefish stock assessment (Haltuch et al., 2019). This is an ongoing project with Melissa Haltuch in the FRAM Division and the Pacific Transboundary Sablefish Assessment Team (PSTAT).
Life-history modeling and mechanism-based oceanographic drivers
Ongoing work examines oceanographic drivers' role on groundfish recruitment with the aims of both 1) better understanding the ecology of the species and 2) providing an environmental index of recruitment for use in stock assessment. We start by building a conceptual life-history model for a species. We then generate stage- and spatiotemporally-specific hypotheses regarding the oceanographic and biological variables that may influence recruitment. We test these hypotheses using observed data and output from oceanographic models to develop mechanism-based models that predict recruitment for the target species. For example, recruitment in sablefish is highest in years with cooler waters leading up to spawning, stronger onshore transport, and warm waters during the egg stage, northern transport at depth yolk-sack stage, and cooler waters during the larval stage.
We have applied this approach to the following species:
- Sablefish Anoplopoma fimbria (Tolimieri et al. 2018)
- Petrale sole Eopsetta jordani (Haltuch et al. 2019)
- Pacific hake (whiting) Merluccius products
For more information on the Center’s Pacific hake work, contact our Cathleen Vestfals and Kristin Marshall.
New projects include applying this same approach to Dungeness crab Metacarcinus magister. Ridouan Bani and Dan Holland in the Human Dimensions team lead the crab project.
Species distribution models, oceanography, and climate
Climate impacts on groundfish fisheries and fishing communities along the US West Coast
In 2020, with support from the David and Lucille Packard Foundation, we began a project to examine climate impacts on groundfish, groundfish fisheries, and fishing communities on the West Coast. The study's overall goals are:
- To improve understanding of how climate variability and change influence groundfishes’ availability to fisheries and fishing communities along the US West Coast.
- To determine how existing fisheries management approaches perform under climate change and in an uncertain future.
We use various modeling tools and field data to link historic groundfish spatial distributions and fishing patterns to climate variables. We will project these distributions and patterns into the future based on:
- Global climate change models.
- Downscaled regional oceanographic models.
- Ecological models for single species and whole food webs and fisheries using the Atlantis ecosystem modeling framework.
We will further explore the implications of these shifts to fishing ports and communities at sea, each of which has distinct groundfish dependency and adaptive capacity to groundfish changes and climate shocks. These efforts support the Pacific Fishery Management Council's Climate and Communities Initiative.
J-SCOPE seasonal ocean forecasts
We collaborate with the J-SCOPE team to apply seasonal ocean forecasts to fishery species, including sardine, hake, and Dungeness crab. These species typically are among the most important in terms of US West Coast landings and revenue. We forecast spatial distributions and habitat of these species and water conditions (hypoxia) and other indicators provided within the California Current Integrated Ecosystem Assessment's ecosystem status report.
Ocean salmon distribution modeling
Chinook salmon Oncorhynchus tshawytscha support a diversity of important commercial and recreational ocean fisheries between California and Alaska and serve as primary prey for the endangered Southern Resident Killer Whale population. To understand how Chinook salmon populations from rivers between California and British Columbia contribute to the ocean, we have developed dynamic population models to estimate stock-specific ocean distributions for all major fall-run Chinook salmon stocks (Shelton et al., 2019). We have extended these models to understand shifts of each stock's ocean distributions in response to sea surface temperature and project future availability for fisheries and predators (Shelton et al., 2020).
Krill (Euphausiacea) Distributions in the California Current and recruitment of Pacific Hake
We use acoustic survey data, species distribution modeling, and climate and oceanographic drivers to understand and predict krill distribution, a vital food resource for many marine fishes, seabirds, and marine mammals. Our goal is to understand the spatial overlap between Pacific hake Merluccius productus and krill to enable predictions of hake distribution, growth, and recruitment to the fishery. The Fisheries Engineering and Acoustic Technologies (FEAT) team leads this project.
Bycatch: whale entanglements and more
Climate variability influences the distributions of both targeted and incidentally caught species. Climate and other factors have shifted the distribution and abundance of protected species and the concentration of fishing activity and different parts of the US West Coast. Our work informs decision-making about reducing the risk of entanglement in fishing gear for range-shifting blue whales, humpback whales, and leatherback turtles while allowing fisheries to thrive on the US West Coast.
Harmful Algal Blooms
IMNSE team members are also working to understand better the climate effects on harmful algal blooms (HABS) that disrupt fisheries and fishing communities.
Ecosystem Considerations for groundfish stock assessments
We developed the Ecosystem Considerations appendix for the 2019 sablefish stock assessment (Haltuch et al., 2019). This document highlights ecological and socio-economic factors related to sablefish ecology and the sablefish fishery's management. While the document’s content covers a broad array of topics, sections addressed climate indicators, including the Pacific Decadal Oscillation (PDO), the timing of the spring transition, and an analysis of the use of sea surface height as an indicator of sablefish recruitment.
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