In the Pacific Northwest, blooms of the diatom Pseudo-nitzschia (PN) sometimes produce domoic acid, a neurotoxin that causes amnesic shellfish poisoning, leading to a Harmful Algal Bloom (HAB) event. The Pacific Northwest (PNW) HAB Bulletin project, a partnership between academic, government, and tribal stakeholders, uses a combination of beach and offshore monitoring data and ocean forecast modeling to better understand the formation, evolution, and transport of HABs in this region. This project produces periodic Bulletins to inform local stakeholders of current and forecasted conditions. The goal of this study was to help improve how the forecast model is used in the Bulletin's preparation through a retrospective particle-tracking experiment. Using past observations of beach PN cell counts, events were identified that likely originated in the Juan de Fuca eddy, a known PN hotspot, and then particle tracks were used in the model to simulate these events. A variety of "beaching definitions" were tested, based on both water depth and distance offshore, to define when a particle in the model was close enough to the coast that it was likely to correspond to cells appearing in the intertidal zone and in shellfish diets, as well as a variety of observed PN cell thresholds to determine what cell count should be used to describe an event that would warrant further action. The skill of these criteria was assessed by determining the fraction of true positives, true negatives, false positives, and false negatives within the model in comparison with observations, as well as a variety of derived model performance metrics. This analysis suggested that for our stakeholders' purposes, the most useful beaching definition is the 30 m isobath and the most useful PN cell threshold for coincident field-based sample PN density estimates is 10,000 PN cells/L. Lastly, the performance of a medium-resolution (1.5 km horizontal resolution) version of the model was compared with that of a high-resolution (0.5 km horizontal resolution) version, the latter currently used in forecasting for the PNW HAB Bulletin project. This analysis includes a direct comparison of the two model resolutions for one overlapping year (2017). These results suggested that a narrower, more realistic beaching definition is most useful in a high-resolution model, while a wider beaching definition is more appropriate in a lower resolution model like the medium-resolution version used in this analysis. Overall, this analysis demonstrated the importance of incorporating stakeholder needs into the statistical approach in order to generate the most effective decision-support information from oceanographic modeling.

A heatwave that blanketed the northeast Pacific Ocean in 2013–2015 had severe impacts on the marine ecosystem through altered species composition and survival. A direct result of this marine heatwave was a sustained, record-setting harmful algal bloom (HAB), caused by the toxigenic diatom, Pseudo-nitzschia, that led to an unprecedented delay in harvest opportunity for commercial Dungeness crab (Metacarcinus magister) and closure of other recreational, commercial and tribal shellfish harvest, including razor clams. Samples collected during a cruise in summer 2015, showed the appearance of a highly toxic “hotspot” between Cape Mendocino, CA and Cape Blanco, OR that was observed again during cruises in the summers of 2016–2018. The transport of toxic cells from this retentive site northward during wind relaxations or reversals associated with storms resulted in economically debilitating delay or closure of Dungeness crab harvest in both northern California and Oregon in 2015–2019. Analyses of historic large-scale Pseudo-nitzschia HABs have shown that these events occur during warm periods such as El Niño, positive phases of the Pacific Decadal Oscillation, or the record-setting marine heatwave. In order to reduce the impacts of large-scale HABs along the west coast of North America, early warning systems have been developed to forewarn coastal managers. These early warning systems include the Pacific Northwest and California HAB Bulletins, both of which have documented elevated domoic acid and increased risk associated with the northern California hotspot. These early warnings enable mitigative actions such as selective opening of safe harvest zones, increased harvest limits during low risk periods, and early harvest in anticipation of impending HAB events. The aims of this study are to show trends in nearshore domoic acid along the US west coast in recent years, including the recent establishment of a new seed bed of highly-toxic Pseudo-nitzschia, and to explore how early warning systems are a useful tool to mitigate the human and environmental health and economic impacts associated with harmful algal blooms.

Abstract Microplastics are an ecological stressor with implications for ecosystem and human health when present in seafood. We quantified microplastic types, concentrations, anatomical burdens, geographic distribution, and temporal differences in Pacific oysters (Crassostrea gigas) and Pacific razor clams (Siliqua patula) from 15 Oregon coast, U.S.A. sites. Microplastics were present in organisms from all sites. On average, whole oysters and razor clams contained 10.95 ± 0.77 and 8.84 ± 0.45 microplastic pieces per individual, or 0.35 ± 0.04 pieces g−1 tissue and 0.16 ± 0.02 pieces g−1 tissue, respectively. Contamination was quantified but not subtracted. Over 99% of microplastics were fibers. Material type was determined using Fourier‐transform infrared spectroscopy. Spring samples contained more microplastics than summer samples in oysters but not razor clams. Our study is the first to document microplastics in Pacific razor clams and provides important coast‐wide data to compare microplastic burden across species, seasons, and sites.

Significance We investigate regulation of domoic acid, a potent marine phycotoxin, at the climate scale. Due to the threat domoic acid can pose to public health, marine wildlife, and coastal economies, decades of laboratory experiments have examined controls on domoic acid production without reaching consensus on reliable toxin-producing conditions. Our findings reveal an association between domoic acid in shellfish and climate-scale warm ocean conditions, a unique, large-scale perspective relative to previous work.

The accumulation of domoic acid (DA) and saxitoxins (STX), phycotoxins produced by some species of Pseudo-nitzschia and Alexandrium, respectively, in coastal food webs are a focus of research on the West Coast of the United States due to the deleterious effects they have on coastal ecosystems and economies. Results are presented from the 2007-2012 Monitoring Oregon Coastal Harmful Algae (MOCHA) project, the Oregon coast's first HAB monitoring and research program. Both historical toxin databases and more detailed case-study observations of individual HAB events are compiled to provide the first detailed overview of HAB occurrence in this region. These results are also presented in the context of informing future HAB monitoring in this and other upwelling regimes affected by STX and DA. A 2009-2010 warming event was associated with the greatest HAB activity during the MOCHA project, including anomalously high sea surface temperatures and shellfish harvesting closures due to STX and DA in 2009 and 2010, respectively. In regards to HAB monitoring, it is shown that (1) razor clams are a more sensitive indicator of DA than mussels; (2) water column concentrations of particulate domoic acid greater than 103 ng L-1 can be used as a threshold for early-warning of shellfish DA toxicity and (3) approximately bi-weekly, or shorter, monitoring of Alexandrium in the surf zone and/or offshore can provide advance notice of STX contamination of shellfish. Both of the latter two metrics gain added value when coupled with local wind stress, a proxy of downwelling/relaxation events that facilitate greater interaction between offshore blooms and shellfish. (C) 2015 The Authors. Published by Elsevier B.V.

Significant seabird mortality on the Oregon (OR) and Washington (WA) coast in 2009 has been attributed to a massive bloom of the dinoflagellate Akashiwo sanguinea (K. Hirasaka) G. Hansen & O. Moestrup. Initial, albeit limited, observations suggested this bloom began in WA and reached OR waters through southward transport. Here, we explore a combination of remote sensing products and an exceptional latitudinal dataset of plankton counts collected in the surfzone and offshore in OR and WA coastal waters. Records of satellite ocean color for this period support the new finding that blooms were concurrent in OR and WA waters, with no evidence for latitudinal propagation as had been previously suggested. Plankton analyses further indicate that there was a rapid and synchronized increase of A. sanguinea between late August and mid-September of 2009 along wide swaths of the OR and WA coasts. Bloom onset occurred during a prolonged quiescent and warm period in late August-early September, near the end of the March-October upwelling phase. An upwelling event in October likely contributed to foam production through vertical mixing of A. sanguinea rich waters. Bloom intensity peaked earlier and at higher levels in WA waters as compared to OR with cell concentrations exceeding 1.5 x 10(6) cells L-1 (WA) and similar to 350,000 cells L-1 (OR). In OR samples, A. sanguinea cells comprised upwards of 90% of dinoflagellate cell counts and similar to 30% of total phytoplankton cells. At some locations, A. sanguinea persisted well into November-December of 2009, during which time satellite sea surface temperature records indicated anomalously warm surface waters (up to similar to 5 degrees C greater than climatological means). Taken together, the data reveal a HAB event of a magnitude unprecedented in over a decade of observations. We hypothesize that these blooms originated from either a cryptic cyst bed and/or a pelagic seed bank of viable vegetative cells. (C) 2014 Elsevier B.V. All rights reserved.

Along the Pacific coast of North America, from Alaska to Mexico, harmful algal blooms (HABs) have caused losses to natural resources and coastal economies, and have resulted in human sicknesses and deaths for decades. Recent reports indicate a possible increase in their prevalence and impacts of these events on living resources over the last 10-15 years. Two types of HABs pose the most significant threat to coastal ecosystems in this "west coast" region: dinoflagellates of the genera Alexandrium, Gymnodinium, and Pyrodinium that cause paralytic shellfish poisoning (PSP) and diatoms of the genus Pseudo-nitzschia that produce domoic acid (DA), the cause of amnesic shellfish poisoning (ASP) in humans. These species extend throughout the region, while problems from other HABs (e.g., fish kills linked to raphidophytes or Cochlodinium, macroalgal blooms related to invasive species, sea bird deaths caused by surfactant-like proteins produced by Akashiwo sanguinea, hepatotoxins from Microcystis, diarrhetic shellfish poisoning from DinophySis, and dinonagellate-produced yessotoxins) are less prevalent but potentially expanding. This paper presents the state-of-knowledge on HABs along the west coast as a step toward meeting the need for integration of HAB outreach, research, and management efforts. Published by Elsevier B.V.