The West Coast HF Radar network is approaching its 20th anniversary as the world’s largest. Data and products have progressed to where HFR surface currents are now assimilated automatically into NOAA WCOFS, are operationally used for search and rescue and spill response and used in studies as diverse as long-term California Current System observations, HAB advection and whale feeding behavior. Ongoing research topics are numerous. Cal Poly SLO is investigating persistent transport patterns (Lagrangian Coherent Structures) in the Morro Bay Wind Energy Area to identify potential ecological hotspots. UCSC is performing an analysis of HFR-derived divergence and COAMPS-modeled wind stress curl on ~10km scales. UCSB researchers recently published a study examining submesoscale eddies in the Southern California Bight based on a 10-year HFR record and are working with WHOI to quantify HFR uncertainties. BML/UCD is working on a decadal summary of flow patterns off California, highlighting regions of onshore/offshore flow, separation of the shelf jet, and persistent mesoscale eddies, to provide new insights for ecosystem studies. NPS and UCSC are measuring offshore river plume evolution through satellite spectral imagery and HFR currents. Novel products and applications are also being developed. CODAR and UCSB began the OTT project, “Improving HF Radar Ocean Observation with AI”, which aims to achieve more accurate observations, inclusion of measurement uncertainties for improved data assimilation, and more efficient calibration. NPS & MLML are investigating RiverSonde currents at Elkhorn Slough to estimate tidal prism for nutrient exchange and erosion/morphological change. Wave products are now being optimized and evaluated from West Coast HFR stations for use by forecasting offices and NWPS stakeholders. Looking forward, HFR researchers and operators are seeking input and collaboration on new products and uses of the network whether climatological like seasonal mean surface currents or integration with other instruments at HFR stations.

The evolution of the 2023-2024 El Niño in the CCS will be presented as observed by the California Underwater Glider Network (CUGN). The CUGN uses Spray underwater gliders making repeated dives from to 500 m every 3 hours and 3 km while measuring temperature, salinity, velocity, dissolved oxygen, chlorophyll fluorescence and acoustic backscatter. The CUGN started in 2005 and continuously occupies three cross-shore CalCOFI lines: line 66.7 off Monterey Bay, line 80 off Point Conception, and line 90 off Dana Point. In 2019, two lines were established at the shelf break (CalCOFI station 60) between lines 80 and 90, and on line 56.7 near Bodega Bay. Past El Niños observed by the CUGN include those in 2009-2010 and 2014-2016. These events were distinguished by anomalously high temperatures and low salinities, consistent with anomalously deep isopycnals. Similar anomalies are already being observed in September 2023. During the very strong El Niño in 2015-2016, anomalously salty water was evident on isopycnals in the poleward flowing California Undercurrent, indicating the influence of advection. This effect was not present during the moderate El Niño of 2009-2010, and it will be telling whether this anomalous saltiness is observed in 2023-2024. The several-year El Niño cycle is embedded in longer decadal variability so that the CCS was anomalously fresh during the 2014-2016 El Niño while CCS waters are salty now. Results in the CCS will be presented in the context of conditions in the equatorial Pacific and in the atmosphere to address the processes that lead to local warming.

The California Cooperative Oceanic Fisheries Investigations (CalCOFI) Program is well known to many for its rich history, originally to service the people of the state of California by providing information related to the crash of its most valuable fisheries at the time, the sardine fishery. It grew to monitor an ecosystem and its work has been foundational for other largescale coastal and oceanic monitoring systems and programs like SCCOOS, CenCOOS, and CCE-LTER. The Scripps Institution of Oceanography’s Pelagic Invertebrate Collection (SIO-PIC) at UC San Diego has worked with NOAA’s Southwest Fisheries Science Center to curate and house physical specimen samples and associated data for research and educational use. Currently, no other technology can collect the type of information locked within these archived samples. This program and its supporting institutions have employed and enriched the personal and professional lives of many: without these people, CalCOFI’s mission cannot not succeed. After a visit to the UC San Diego Library Archives, we were inspired to share some early history of CalCOFI, the Scripps Marine Life Research Group, and the value of archived material and research for understanding our environment and natural resources. As we celebrate this program’s 75th year, we highlight the human and physical specimen component of the longest-running integrated oceanographic time-series in the U.S. EEZ.

Marine research stations (MRS) have a critical role in ocean observing systems (OOS) as cross-disciplinary observatories embedded in sensor networks. MRS are place-based facilities that enable research and experiential education through access to the ocean at the same time as engaging with local community and tracking local conditions. As we built out the OOS the initial focus was on distributed networks of automated sensors, but as it matures, we are wrestling with three challenges: obtaining more ecological data, developing deeper community engagement, and adding value to data to support decisions. MRS are strong in California and underutilized as place-based nodes within the OOS. What opportunities exist? How do we extrapolate local ecosystem studies at a few MRS sites across a network of sites with only sensor-based information? How do we leverage the education and community engagement at MRS sites? How do we integrate contemporary distributed sensor data and model output with site-specific experimental data and long-term environmental data? This challenge straddles and potentially integrates traditionally separate themes in coastal resilience, habitat state, ocean acidification, hypoxia, harmful algal blooms, pollution, fisheries, infrastructure, and recreation. As we look back at on-site data and forward at a long-term commitment to data collection, MRS are essential observatories along our coast. The promise of improved integration of MRS in OOS includes new partnerships and resources as well as insight and innovation, enhancing the output and impact of ocean observing systems.

The Scripps Institution of Oceanography (SIO) Shore Stations Program began measuring temperature and salinity using manually collected daily water samples at the newly constructed pier in August 1916. Additional stations spanning Washington, Oregon, and California began collecting data as early as 1919. The SIO pier data is the longest continuous record in the Pacific Rim. Today, 10 temperature stations continue in California with six also measuring salinity. The program exemplifies the value of uniformly collected long-term data for quantifying ocean and regional climate change not possible by any other means. In this presentation we show early program history, indicate advantages and shortcomings of the data including adjustments needed for sampling bias, show how the data supplement automated shore stations programs, and discuss scientific results like contextualizing marine heat waves and extracting regional rainfall fluctuations from salinity data. We also seek feedback and discussion concerning opportunities for collaboration and data sharing with related data sampling programs and research projects. Program details and access to all data are at https://shorestations.ucsd.edu/. The Shore Stations Program is funded by California State Parks, Natural Resources Division.

For over a decade, the ocean modeling group at University of California Santa Cruz has been developing and analyzing configurations of the Regional Ocean Modeling System for the California Current as well as data assimilative strategies to maximize benefits from ocean observations. Major advances include a multi-decadal historical set of data assimilative reanalyses, a near real-time data assimilative nowcast, biogeochemical data assimilation, forward and assimilative carbonate chemistry components, climate projections, and high resolution nested configurations. This talk will review a subset of these developments that take advantage of the extensive network of data collected by the California ocean observing system and also review applications of model products.

In late 2007, NOAA Fisheries Southwest Fisheries Science Center and Cal Poly Humboldt initiated a time series of year-round ocean observation cruises along what is now known as the Trinidad Head Line. Since then, this growing suite of observations has matured as a source of information on the structure and state of the ocean in an understudied region of the California Current Ecosystem that contributes to coastwide ecosystem assessments, and has attracted additional observation capabilities to the region. Our work has characterized changes in the plankton community across a wide range of climate variability, including El Ninos, La Ninas, and marine heatwaves, documenting shifts in plankton assemblage structure (e.g., the arrival of southern species during warming events), the characteristics of the dominant krill species Euphausia pacifica, and the intensity of harmful algal blooms. Importantly, the length and continuity of our observations now allow us to develop ocean-indicators for the performance of regional salmon stocks, including Klamath River Fall Run Chinook, a linchpin species for management of the coastwide salmon fishery, and have set the stage for developing augmented observation systems to assess the effects of wind energy development on the ecosystems of coastal waters off northern California.

For the past 12 years, the CCIEA (California Current Integrated Ecosystem Assessment) team has produced an annual ecosystem status report (ESR) primarily for use by the PFMC (Pacific Fisheries Management Council), but accessible to other interested stakeholders. This report is ~20 pages (with an additional ~100 pages of appendices), and includes contributions from > 90 individuals from across 23 different institutions/agencies, and in many ways is similar to the older versions of the CalCOFI State of the California Current Report. The majority of the data comes from observations, with a small amount of modeled data as well, along with human dimensions data some of which comes from surveys. Combining all this disparate data into a cohesive “story” for management “ingestion” is a challenge, especially in finding the balance between detail and “digestibility”. Here we will discuss the lessons learned from this exercise, including (but not limited to) our logistical production methodology (a recent switch to Rmarkdown), our process for data intake and inclusion, and ultimately our interface with management. Additional examples of where (and why) we’ve had our most successful engagements will be explored specifically in terms of translating observational data into analyses and presentations that most resonated with management.

The California Current Ecosystem (CCE) Long-Term Ecological Research (LTER) site is part of the larger LTER Network, founded in 1980 by the National Science Foundation with the recognition that long-term field research could help unravel the principles and processes of ecological science, which frequently involve long-lived species, legacy influences, and rare events. A primary goal of the LTER Network is to understand a diverse array of ecosystems at multiple spatial and temporal scales. CCE LTER represents the most pelagic marine-oriented site in the LTER Network, leveraging the 75-year California Cooperative Oceanic Fisheries Investigations (CalCOFI) ocean time series which has demonstrated physical forcing on multiple spatiotemporal scales with concomitant impacts on ocean biota. A core principle of CCE science is that intensive process-oriented experimental studies can be synthesized with modeling approaches to quantify functional relationships within the system, which can then be related to longer-term in situ and remotely sensed time-series measurements. These time-series measurements in turn serve as validation tools for improving models and for extrapolating the results of experimental studies and conducting retrospective analyses into past changes in the system. This presentation will highlight ongoing research in CCE LTER, which during this grant cycle focuses on marine heatwaves, ecological stoichiometry, and top-down pressure in a coastal upwelling biome.

The Applied California Current Ecosystem Studies (ACCESS) is a public/private partnership founded in 2004 that supports marine wildlife conservation and healthy marine ecosystems in north-central California by conducting ocean research to inform resource managers, policy makers, and conservation partners. We collect data on oceanography, low/mid-trophic levels, and top marine predators. Oceanography data includes water sample collections (surface and at depth for ocean acidification and nutrients monitoring) and CTD casts at predetermined stations, and continuous measurements (TSG). For low and mid-trophic levels, we collect phytoplankton with a net, zooplankton with hoop and Tucker trawls at predetermined stations, as well as continuous passive acoustic sampling for krill and fish detection. Data for top marine predators include bird and mammal observations through standardized strip and line transects. The main research topics and management issues we aim to address include: 1) reducing ship strikes, 2) reducing whale entanglements, 3) protecting wildlife hotspots, 4) developing ecosystem indicators, and 5) tracking ocean acidification. We produce an annual ‘Ocean Climate Indicators Report’ that provides information about the status and trends of physical and biological climate change indicators in the region. ACCESS data are available in the California Integrated Ocean Observing System (CalIOOS) Data Portal. ACCESS data informs about 20% of the indicators included in the Cordell Bank and the Greater Farallones National Marine Sanctuaries Condition Reports. ACCESS data has been used by graduate students associated with the California State University system and the University of California Davis. ACCESS data have been used in recent publications including an analysis of krill and baleen whale distributions in relation to submesoscale surface current features, incorporation of ocean acidification data into a U.S. West Coast dataset on ocean stressors, and an analysis on the impacts of warming and ocean acidification on pteropods.

We have developed a skillful suite of prediction systems at multiple timescales for use in assessing weather, storm tracks, and long-term change to maximize human safety and minimize storm repair costs. Here we propose a similar framework for the ocean, from physics to fisheries to help maximize sustainable fisheries while minimizing impact on protected species from sharks, turtles, seabirds to marine mammals. The different timescales of prediction carry different skills and different management applications including nowcasts on where species are most likely distributed, forecasts of indices such as habitat compression and temperature thresholds to reduce and avoid entanglements, and projections of species distribution for use in long term planning (e.g. sanctuaries and wind energy planning). This suite of prediction scales can be used to create a holistic approach towards marine resource management, with the goal of reducing risk and rewarding opportunity in the face of climate variability and change.

The 2014-2016 marine heat wave (MHW) caused a mass mortality event for giant kelp canopies in the Southern California Bight (SCB) due to low nutrients and high temperatures. Despite the uniformity of temperature increase, response of kelp was non uniform. Here we use a highly resolved physical biogeochemical model to identify kelp canopy regions with high occurrences of nutrient limitation as well as those which experience beneficial levels of nutrients from anthropogenic sources such as wastewater outfalls and rivers. We then examine the results in the context of MPA’s in Southern California, merging in situ observations, remote sensing, and physical biogeochemical modeling.

Mechanistic models grounded in first principles (i.e., physiology) when coupled to ocean circulation models are useful to retrospectively test recruitment hypotheses. Here, a coupled biophysical individual-based model for Shortbelly rockfish (Sebastes jordani), a non-commercial, yet ecologically important species of the California Current System, is used to evaluate the relative influence of starvation mortality and advective losses on recruitment across historical El Niño Southern Oscillation (ENSO) events. Leveraging biological data from a fisheries-independent survey along with model output, we show that starvation had a larger effect on modeled recruitment than did retention during El Niño events and both starvation and modeled recruitment explain the timing and magnitude of observed recruitment. In contrast, retention over the continental shelf had a larger effect on modeled recruitment during La Niña events and while retention alone could not explain the timing of observed recruitment, modeled recruitment was positively associated with observed recruitment for one of the two La Niña years and when both La Niña events were combined. The preponderance of recruitment variability being differentially driven by food web-dependent and transport-dependent processes amongst a backdrop of contrasting environmental conditions (ENSO events) emphasizes the importance of context-dependency when studying mechanisms of recruitment variability.

Ocean models can predict how the California Current and North Pacific Ocean will change. However, the response of upper trophic levels is still debated and requires ongoing measurements of their behavior and distribution as their habitat changes. Preliminary observations suggest a northward shift with some species, like California sea lions, breeding on islands that had previously been only used as haul-out sites. With support from CENCOOS, we have been monitoring the movement and foraging behavior of northern elephant seals since 2004 and have recently restarted observations of California sea lion foraging behavior in Central California. An advantage of deploying electronic tags on seals is that they can also provide repeat measurements of the physical environment (chlorophyll, salinity, oxygen, temperature, and contaminant distribution). For example, elephant seals foraging in the Gulf of Alaska have lower tissue mercury levels than individuals foraging along the North Pacific Transition Zone. Further, deeper-diving individuals have higher mercury loads than shallower-diving individuals. We will review our ongoing measurements of upper trophic level predators in the California Current and Eastern North Pacific Ocean.

The increase in the white shark population in the Northeast Pacific and the juvenile use of coastal waters has increased concern over public safety. The CA Shark Beach Safety Program was started in 2018 with a research, education and outreach arm. Research has focused on understanding and predicting juvenile white sharks use of beach habitats and sharks were tagged with acoustic and satellite transmitters to monitor movements. Monitoring has helped determine how environmental conditions influence season migration and how prey densities alter aggregation densities and fidelity. Realtime acoustic monitoring and drone monitoring has improved lifeguard beach safety management. Environmental and white shark monitoring data are served via ERDDAP server and shared via SCCOOS for public access.

With funding from the Marine Biodiversity Observation Network (MBON) program (NASA and NOAA), MBARI and CeNCOOS collaborate with ongoing routine ecosystem observation programs and augment them with sampling for environmental DNA (eDNA). This effort that began in 2014, with augmentation of MBARI ship time series and autonomous vehicle programs, has since been expanded to include the Rockfish Recruitment and Ecosystem Analysis Surveys (RREAS), the Applied California Current Ecosystem Studies (ACCESS), the Trinidad Head Line (THL), PISCO Marine Protected Area kelp forest monitoring, and Monterey Bay National Marine Sanctuary (MBNMS) surveys. This presentation summarizes the sampling effort to date presents a few selected examples of results to date. It emphasizes the added value that eDNA information provides to the understanding of the biodiversity in the CCC and how it varies over space and time.

The California Collaborative Fisheries Research Program (CCFRP) is a collaborative science program that works with volunteer anglers and standardized hook-and-line, catch-and-release fishing surveys to monitor recreationally-targeted fishery species inside and outside of marine protected areas (MPAs) across California. The ongoing program has 17 years of data from Central California and 7 years of data statewide, allowing us to evaluate not only fish community responses to MPA protection, but also a range of other factors that may affect fish communities. We assessed changes in abundance, size structure, and biomass for fishes inside and outside MPAs over time. We found that MPAs generally have positive effects on a range of fish community response metrics, and we identified other of MPA attributes (e.g., MPA size, age) that impact the strength of those responses. Furthermore, we explored the 17-year time series from the Central Coast to examine how MPAs influenced fish community responses to and recovery from the 2014-2016 Marine Heat Wave (MHW) event and more broadly how oceanographic variation may impact fish populations. We found that abundance and community structure changed dramatically during the MHW event similarly inside and outside of MPAs. However, fish diversity recovered much more quickly inside MPAs, suggesting that MPA protection may improve resilience to disturbance. In addition, we found that abundance of some smaller, lower-trophic level rockfishes was strongly correlated with oceanographic variation, but that abundance of other higher trophic level rockfishes was less strongly related to oceanographic variation. Finally, we also found evidence of fishing-the-line behavior and edge effects, which may moderate the strength of MPA responses, especially in smaller MPAs. These findings emphasize the value of long-term collaborative datasets such as CCFRP in addressing a wide range of questions that can improve management of fisheries as they adapt to changes in climate and fisher activities.

Marine heatwaves can drive large-scale shifts in marine ecosystems, but studying their impacts on comprehensive assemblages across multiple trophic levels is difficult. In this study, we paired microscopy with environmental DNA (eDNA) metabarcoding of the ethanol preservative of the California Cooperative Oceanic Fisheries Investigations (CalCOFI) ichthyoplankton biorepository spanning a 23-year time series. This biorepository captures major and sometimes unexpected changes to fish and zooplankton assemblages in the California Current Large Marine Ecosystem during and after the 2014–2016 Pacific Marine Heatwave. Using both data sources, we modeled patterns of tropicalization in the California Current, with increases in southern, mesopelagic species and associated declines in commercially important temperate fish species (e.g., North Pacific Hake and Pacific Sardine). Our results show shifts in fisheries assemblages (e.g., Northern Anchovy) even after the return to average water temperatures, corroborating ecosystem impacts found through multiple traditional surveys of this study area. We further provide novel insights into both larval Rockfish (Sebastes sp.) assemblages that largely lack the distinctive morphological characteristics necessary for species level identification. Likewise, we successfully characterized hundreds of large zooplankton (>505µm) species from CalCOFI preserved samples, allowing for the identification and characterization of key fisheries target larvae, imperiled species (sea stars), and key foundational zooplankton taxa (e.g. copepods, krill) within the longest running paired biological and carbonate chemistry time series. This pilot data directly informs a burgeoning research effort to produce a nearly three-decade long climate-grade zooplankton time series to fill a critical missing component of zooplankton biomonitoring in the CCLME. This work will provide NOAA and the state of California the data needed to track changes in foundational prey bases and the development of a framework for an early warning eDNA warming, ocean acidification, and hypoxia assessments.

Marine ecosystem and oceanographic datasets are information-rich with respect to physical and biological patterns at multiple spatial and temporal scales. Such data can serve as a basis for generating research investigations that exhibit both scientific or management value and novelty from a data science perspective. This creates opportunities for collaborations with strong potential to produce contributions in multiple areas. In this talk we discuss student-centered approaches to developing marine science/data science collaborations through partnerships with data science capstone programs and degree programs in statistics. We focus on a current project leveraging genetic metabarcoding data and marine mammal sightings collected from CalCOFI cruises to identify potential indicators of common whale species from among relative abundances of microorganisms after adjusting for seasonal trends and the influence of physical variables. Initial results, methodological novelties of the analysis, and student involvement and contributions are discussed. Past projects are also briefly mentioned, including data-centric communication- and outreach-oriented work developing interactive data applets and data storytelling tools, along with reflections on how such opportunities contributed to student outcomes.

Microplastics (MPs; 20 µm to 5 mm in diameter) are ubiquitous pollutants in marine environments. A major source of MPs is anthropogenic, plastic-littered effluent draining into coastal waters worldwide including here in southern California. The Southern California Bight (SCB) is inhabited by subpopulations of Pacific sardines, Sardinops sagax, a commercially and ecologically important fish. Pacific sardines filter-feed on zooplankton whose body size falls within the same size range as marine MPs and therefore are vulnerable to ingestion. The goals of this study were to: 1) determine whether sardines were ingesting MPs and if so, 2) determine whether the ingested MPs were then assimilated into body tissues. MPs were chemically extracted from 30 sardine stomachs, livers, and axial muscle tissues. We used fluorescent microscopy combined with Nile Red staining to quantify and measure the Feret’s diameter of extracted MPs using MP-VAT software. We found that the average (± SD) micro-particle size of ingested MPs was 183 ± 428 ìm, whereas assimilated MPs in the muscle tissue were 31 ± 10 ìm and 325 ± 439 ìm in the liver. Muscle filets had an average (± SD) MP weight (mg) per muscle tissue wet weight (g) of 13.2 ± 4.77 mg g-1, 44 times higher than other Sardinops sp. measured. Fourier Transform Infrared (FTIR) spectroscopy analyses showed that the dominant MPs in muscle tissues were polytetrafluoroethylene (fishing line), low-density polyethylene (LDPE; plastics bags), rayon (R; clothing), and polyvinyl chloride (PVC; irrigation pipe). This study demonstrates that wild-caught S. sagax from the SCB do regularly ingest and assimilate microplastics into muscle and liver tissues. The research offers empirical evidence of microplastic ingestion by S. sagax along the Southern California coast, revealing elevated levels of MP contamination compared to similar studies.

Several factors make domestic development of marine farming critical: 1) The world population is growing to 10 billion in 25 years, 2) The US imports over $19 billion in seafood annually of which at least 50% is farmed, and 3) Traditional terrestrial farming of animal protein is a major contributor of climate change. The productivity of US seafood resources must be expanded to meet increasing domestic demand and to offset the growing seafood trade deficit. The greatest opportunity to realize this needed production is to use the open ocean where conflicts with other users are minimized, water quality is high and the impacts of operations to the environment can be mitigated. The FAO has surveyed the globe and has reported that the US has the greatest abundance of areas that meet the three primary criteria for marine farming development: workable proximity to commercial ports, appropriate depth and proper current flow. However, any development in US waters requires a rigorous regulatory review. Specific permits are required from the Army Corps of Engineers and from the Environmental Protection Agency, and farming operations have to be conducted under existing USDA and FDA authorities for the production of food. Development of these permits is subject to environmental review under the National Environmental Policy Act through consultation with all federal and state agencies responsible for management of natural resources. Marine Spatial Planning can provide some of the information needed to assess and mitigate some potential impacts, but oceanographic information (temperature, primary productivity, current speed and direction) is needed to develop a wide range of answers to questions regarding systems engineering, biological performance and economic viability. The Ocean Observing system can provide the information needed to minimize environmental impacts and maximize economic viability needed to provide a new domestic source sustainably grown seafood.

In the near future, California’s marine ecosystems will be impacted by the construction, operation, and maintenance of offshore wind energy infrastructure. Offshore wind activities will affect marine organisms both directly (e.g. turbine collisions with flying organisms, habitat disturbance) and indirectly (e.g., via upwelling attenuation, prey aggregation, or other food web effects). Impacts of offshore wind development on California’s marine ecosystems are likely to vary throughout the year, as seasonal productivity-generating processes strongly influence the distribution and behavior of resident and transient species throughout the region. Seabirds are a particularly useful sentinel species for highlighting seasonal variability in productivity, as they are highly conspicuous at sea and shifts in their community composition and distributions reflect immediate changes in the environment. While much work has already been done on the potential interactions between offshore wind energy development and seabirds in the California Current, we lack a clear understanding of how interactions may vary seasonally and the resulting impacts on seabird populations. Fortunately, the Farallon Institute has curated at-sea seabird survey data in southern and central California covering three seasons from 1987 to 2023 aboard CalCOFI cruises. Here, we build upon previous work to map direct risks to seabirds from wind energy infrastructure within CA by using joint dynamic species distribution models (e.g. VAST) to map seasonal seabird distributions throughout the CalCOFI area, including in the planned Morro Bay wind energy area. Seasonal maps are employed to highlight how the likelihood and type of exposure risk changes across the year for California’s nearshore and offshore seabird communities.

In California offshore waters, sustained northwesterly winds have been identified as a key resource that can contribute substantially to renewable energy goals. However, the development of large-scale offshore wind farms can reduce the wind stress at the sea surface, which could affect wind-driven upwelling, nutrient delivery, and ecosystem dynamics. Here we examine changes to upwelling using atmospheric and ocean circulation numerical models together with a hypothetical upper bound buildout scenario of 877 turbines spread across three areas of interest. Wind speed changes are found to reduce upwelling on the inshore side of windfarms and increase upwelling on the offshore side. These changes, when expressed in terms of widely used metrics for upwelling volume transport and nutrient delivery, show that while the net upwelling in a wide coastal band changes relatively little, the spatial structure of upwelling within this coastal region can be shifted outside the bounds of natural variability. In the light of these projected changes from offshore wind farm development, a robust ocean observing system will be needed in and around wind energy areas to measure changes in atmospheric forcing, along with any potential ocean and ecosystem response. Here, data gaps in atmospheric and oceanic processes are addressed and ocean observing needs are outlined to establish baseline conditions and measure potential changes post-wind turbine installation.