I am an Environmental Scientist for the California Department Fish and Wildlife and the Office of Oil Spill Prevention and Response. I conduct research to investigate and monitor health and pathology of marine birds to support the best achievable care of oiled wildlife, and to detect emerging threats to seabird populations. Supervisors: Laird Henkel , Raphael Kudela, and James T. Harvey Address: Marine Wildlife Veterinary Care & Research Center Office of Spill Prevention and Response California Department of Fish and Wildlife 151 McAllister Way Santa Cruz, CA 95060
Examinations of seabirds from oil spills provide resource managers demographic and trauma related... more Examinations of seabirds from oil spills provide resource managers demographic and trauma related data that inform damage assessments for affected species. We examined black skimmers (Rynchops niger; n = 49) from the Deepwater Horizon oil spill for demographics, ingested petroleum, and plastics. The majority were hatch-year males in poor body condition (57%), with atrophied, dehydrated, or pale organs possibly attributed to external oil exposure. Six (12%) black skimmers had evidence of external oiling, three (6%) were fouled by crude oil, one (2%) had biological fouling, and two (4%) were fouled in a synthetic substance, suspected to be chemical dispersant. Damage to organs suggested that internal examinations should be performed alongside external surveys to provide a thorough understanding of the total number of individuals impacted by a spill, and that timely internal examinations are essential. No evidence of ingested petroleum or plastics was found.
Common ravens (Corvus corax; ravens) are known nest predators that have the ability to negatively... more Common ravens (Corvus corax; ravens) are known nest predators that have the ability to negatively impact nesting birds, including imperiled species of seabirds and shorebirds. We conducted systematic necropsies of ravens that were lethally controlled in Monterey Bay, California, USA during 2013-2015, in or near western snowy plover (Charadrius nivosus nivosus) nesting areas, in an effort to better understand body condition, overall health, and diet of individual ravens. Raven predation of snowy plover nests has increased over the years in the Monterey Bay study area, and lethal removal of ravens has been employed to reduce predation. Most ravens examined in this study were in moderate to excellent body condition and also exhibited good organ health. There were statistically significant differences between male and female morphometrics (mass, culmen length, and wing length; P < 0.05). Stomach content analysis indicated a varied diet with consumption of animal remains and eggshell fragments, and anthropogenic sources of food (e.g., human food items and human-produced nonfood items). Our study provides evidence that lethal control of ravens targeted some individual ravens that were responsible for depredating snowy plover nests.
The Central Coast Marine Bird Health Study enhanced response capabilities during unusual mortalit... more The Central Coast Marine Bird Health Study enhanced response capabilities during unusual mortality events in support of OSPR oil spill response and established a regional information center for federal, state, and local resource managers for issues regarding marine bird health. During three years of the CDFG-OSPR SSEP sponsored Seabird Health Study, we systematically quantified human-related and natural causes of mortality based on field studies and lab necropsies (2005, n = 157; 2006, n = 302; 2007, n = 390) and found that although natural mortality factors comprised a significant proportion of determined cases (68%), anthropogenic causes of morbidity and mortality such as chronic oiling, trauma, and fishery interactions continue to be considerable (~15%). Nearshore species (grebes, loons, surf scoters) were more frequently impacted by harmful algal blooms compared with offshore species (murres, shearwaters). We characterized the demography of several unusual mortality events increasing the understanding of causes behind seabird wrecks in the area, including those affecting phalaropes, puffins, fulmars and others. In addition to routine necropsies, we examined post-litigation samples from three past oil spill events: 1997 Kure (n = 602), 1999 Stuyvesant (n = 334), and the 2001-02 San Mateo Mystery Spill (n= 169, aka Luckenbach). We found demographic differences among Common Murres collected during these spill events related to the season and phenology of this species. Winter spills affected mainly adults (60 to 63%) and late summer spill affected significantly more chick-rearing males (15:1 sex ratio). These results provide important information to determine appropriate mitigation measures for effective wildlife restoration. We also provided the CDFG- Petroleum Chemistry Lab with 109 oiled feather samples to help identify non-point source spills and aid in OSPR’s natural resources damage assessment (NRDA) process.
The goal of this study was to determine trends and sources of chronic oiling and other mortality ... more The goal of this study was to determine trends and sources of chronic oiling and other mortality factors affecting marine birds in central California, provide this information to California Department of Fish and Game Office of Spill Prevention and Response (CDFG-OSPR) to determine the species and populations affected by oil, and to help guide appropriate mitigation and restoration actions. This information is central to CDFG-OSPR’s mission “to provide best achievable protection of California&#39;s natural resources by preventing, preparing for, and responding to spills of oil and other deleterious materials, and through restoring and enhancing affected resources.” Specifically, our objectives were to 1) quantify and document trends in chronic oiling and other mortality factors by conducting necropsies of seabirds collected by beach survey programs, rehabilitation centers, and state and federal resource agencies, 2) identify sources of oil by analyzing oiled feather samples and comparing them to known specimens at the CDFG-OSPR Petroleum Chemistry Lab (PCL), and 3) increase understanding of the population-level affect of oil spills on marine birds by examining post-litigation specimens. Our results indicate chronic oiling is the cause of 1 to 4% of annual mortality of marine birds in central CA. Species groups most affected by chronic oiling were alcids, loons, grebes, cormorants, pelican, procellarids, phalaropes, and gulls; these same species are also those most affected by catastrophic oil spills. We found several other mortality factors which continue to affect CA seabirds, including fishery entanglement, trauma, biotoxins, and to a lesser extent, plastic ingestion. We found that demographic impacts of oiling events depend upon the season in which the oil spill occurs. Winter events such as Luckenbach spills affected first year birds more than adults whereas late summer and fall spills (e.g, Kure, Stuyvesant) affected more adults than expected. These results may be useful in determining population-level impacts of both chronic and catastrophic oiling events in the future and designing appropriate mitigation plans.
Bycatch during fishing activities is one of the greatest threats to many seabird species across t... more Bycatch during fishing activities is one of the greatest threats to many seabird species across the global ocean (Anderson et al., 2011; Croxall et al., 2012; Lewison et al., 2014). While gearand region-specific techniques can be used to reduce or mitigate seabird bycatch (e.g., Gilman, 2011; Løkkeborg, 2011; Melvin et al., 2014), it remains a significant issue for many seabird populations, especially due to their life history characteristics: long-lived, delayed maturity, and low fecundity. Beyond the impact of removing an individual from the population, disproportionate mortality of individuals of a particular age or sex can have complex and significant demographic impacts (Gianuca et al., 2017; Tuck et al., 2015). Therefore, characterizing the demographic composition of bycatch is essential to understanding its impacts. Demographic biases in seabird bycatch have been observed globally, with regional patterns of sex and age class biases indicating frequent male adult bias in subpo...
Oil spills in coastal California are a conservation concern for many seabird species and are amon... more Oil spills in coastal California are a conservation concern for many seabird species and are among the top threats to wintering populations of Aechmophorus grebes. Western Grebes A. occidentalis and Clark’s Grebes A. clarkii are sister taxa that breed in freshwater lakes throughout western North America and predominantly spend the nonbreeding season in the nearshore marine environment, where they are vulnerable to oiling (Storer & Nuechterlein 1992). In California, Western Grebes are one of the main species impacted by oil spills (California Department of Fish and Game [CDFG] 1969a,b; Straughan 1970, 1971; American Trader Trustee Council 2001; Hampton et al. 2003; Carter 2003; CDFG et al. 2004; CDFG & US Fish and Wildlife Service [USFWS] 2008; Humple 2009; Oiled Wildlife Care Network [OWCN] / PRBO Conservation Science unpubl. data). Understanding demographic parameters — such as sex and age ratios — of impacted populations is critical to assessing immediate and potential long-term e...
Microcystin toxin is a known environmental stressor with implications for ecosystem harm througho... more Microcystin toxin is a known environmental stressor with implications for ecosystem harm throughout many inland waterways in California. This purported freshwater toxin has recently emerged in the marine environment in Monterey Bay. Microcystin abundance and frequency, as well as environmental variables that drive toxin production in the Monterey Bay area were examined by deploying Solid Phase Adsorption Toxin Tracking (SPATT) samplers and evaluating water samples for 3 years. Microcystin was found in 15 of 21 monitored sites and was shown to be correlated with anthropogenic nutrient loading. Because it is relevant to identify an indicator organism to better monitor this toxin, uptake and release of microcystin toxin in California mussels (Mytilus californianus), and commercial oysters (Crassostrea sp.) were also examined. To provide environmental relevancy Mytilus sp. were also collected at 4 sites in San Francisco Bay for 6 months and analyzed for microcystin toxin. The results in...
San Francisco Bay (SFB) is a eutrophic estuary that harbors both freshwater and marine toxigenic ... more San Francisco Bay (SFB) is a eutrophic estuary that harbors both freshwater and marine toxigenic organisms that are responsible for harmful algal blooms. While there are few commercial fishery harvests within SFB, recreational and subsistence harvesting for shellfish is common. Coastal shellfish are monitored for domoic acid and paralytic shellfish toxins (PSTs), but within SFB there is no routine monitoring for either toxin. Dinophysis shellfish toxins (DSTs) and freshwater microcystins are also present within SFB, but not routinely monitored. Acute exposure to any of these toxin groups has severe consequences for marine organisms and humans, but chronic exposure to sub-lethal doses, or synergistic effects from multiple toxins, are poorly understood and rarely addressed. This study documents the occurrence of domoic acid and microcystins in SFB from 2011 to 2016, and identifies domoic acid, microcystins, DSTs, and PSTs in marine mussels within SFB in 2012, 2014, and 2015. At least ...
From August through December 2015, beachcast bird survey programs reported increased deposition o... more From August through December 2015, beachcast bird survey programs reported increased deposition of common murres ( Uria aalge) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August-October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n=35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center (NWHC) and harmful algal bloom toxins at the University of California, Santa Cruz and the National Oceanographic and Atmos...
The demographic consequences of oil spills or other mortality events for breeding seabird populat... more The demographic consequences of oil spills or other mortality events for breeding seabird populations depend on the age and sex composition of the affected population. Differential wintering by sex and age classes occurs in many migratory bird species, and can have ...
From August through December 2015, beachcast bird survey programs reported increased deposition o... more From August through December 2015, beachcast bird survey programs reported increased deposition of common murres ( Uria aalge) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August-October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n=35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center (NWHC) and harmful algal bloom toxins at the University of California, Santa Cruz and the National Oceanographic and Atmos...
Domoic acid and saxitoxin in seabirds in the United States between 2007 and 2018, 2021
As harmful algal blooms (HABs) increase in magnitude and duration worldwide, they are becoming an... more As harmful algal blooms (HABs) increase in magnitude and duration worldwide, they are becoming an expanding threat to marine wildlife. Over the past decade, blooms of algae that produce the neurotoxins domoic acid (DA) and saxitoxin (STX) and documented concurrent seabird mortality events have increased bicoastally in the United States. We conducted a retrospective analysis of HAB related mortality events in California, Washington, and Rhode Island between 2007 and 2018 involving 12 species of seabirds, to document the levels, ranges, and patterns of DA and STX in eight sample types (kidney, liver, stomach, intestinal, cloacal, cecal contents, bile, blood) collected from birds during these events. Samples (n = 182) from 83 birds were examined for DA (n = 135) or STX (n = 17) or both toxins simultaneously (n = 30), using ELISA or LCMS at the National Oceanographic and Atmospheric Administration, National Marine Fisheries Service (NOAA-NMFS) Wildlife Algal-toxin Research and Response Network (WARRN-West) or the University of California, Santa Cruz (UCSC). DA or STX was detected in seven of the sample types with STX below the minimum detection limit in blood for the three samples tested. DA was found in 70% and STX was found in 23% of all tested samples. The ranges of detectable levels of DA and STX in all samples were 0.65-681,190.00 ng g − 1 and 2.00-20.95 ng g − 1 , respectively. Cloacal contents from a Pacific loon (Gavia pacifica) collected in 2017 from Ventura County, California, had the highest maximum level of DA for all samples and species tested in this study. The highest level of STX for all samples and species was detected in the bile of a northern fulmar (Fulmarus glacialis) collected in 2018 from San Luis Obispo County, California. DA detections were consistently found in gastrointestinal samples, liver, bile, and kidney, whereas STX detections were most frequently seen in liver and bile samples. Co-occurring HAB toxins (DA and STX) were detected in white-winged scoters (Melanitta deglandi) in 2009, a Brandt's cormorant (Phalacrocorax penicillatus) in 2015, and a northern fulmar and common murre (Uria aalge) in 2018. This article provides DA and STX tissue concentrations and patterns in avian samples and shows the utility of various sample types for the detection of HAB toxins. Future research to understand the pharmacodynamics of these toxins in avian species and to establish lethal doses in various bird species would be beneficial.
Examinations of seabirds from oil spills provide resource managers demographic and trauma related... more Examinations of seabirds from oil spills provide resource managers demographic and trauma related data that inform damage assessments for affected species. We examined black skimmers (Rynchops niger; n = 49) from the Deepwater Horizon oil spill for demographics, ingested petroleum, and plastics. The majority were hatch-year males in poor body condition (57%), with atrophied, dehydrated, or pale organs possibly attributed to external oil exposure. Six (12%) black skimmers had evidence of external oiling, three (6%) were fouled by crude oil, one (2%) had biological fouling, and two (4%) were fouled in a synthetic substance, suspected to be chemical dispersant. Damage to organs suggested that internal examinations should be performed alongside external surveys to provide a thorough understanding of the total number of individuals impacted by a spill, and that timely internal examinations are essential. No evidence of ingested petroleum or plastics was found.
Common ravens (Corvus corax; ravens) are known nest predators that have the ability to negatively... more Common ravens (Corvus corax; ravens) are known nest predators that have the ability to negatively impact nesting birds, including imperiled species of seabirds and shorebirds. We conducted systematic necropsies of ravens that were lethally controlled in Monterey Bay, California, USA during 2013-2015, in or near western snowy plover (Charadrius nivosus nivosus) nesting areas, in an effort to better understand body condition, overall health, and diet of individual ravens. Raven predation of snowy plover nests has increased over the years in the Monterey Bay study area, and lethal removal of ravens has been employed to reduce predation. Most ravens examined in this study were in moderate to excellent body condition and also exhibited good organ health. There were statistically significant differences between male and female morphometrics (mass, culmen length, and wing length; P < 0.05). Stomach content analysis indicated a varied diet with consumption of animal remains and eggshell fragments, and anthropogenic sources of food (e.g., human food items and human-produced nonfood items). Our study provides evidence that lethal control of ravens targeted some individual ravens that were responsible for depredating snowy plover nests.
The Central Coast Marine Bird Health Study enhanced response capabilities during unusual mortalit... more The Central Coast Marine Bird Health Study enhanced response capabilities during unusual mortality events in support of OSPR oil spill response and established a regional information center for federal, state, and local resource managers for issues regarding marine bird health. During three years of the CDFG-OSPR SSEP sponsored Seabird Health Study, we systematically quantified human-related and natural causes of mortality based on field studies and lab necropsies (2005, n = 157; 2006, n = 302; 2007, n = 390) and found that although natural mortality factors comprised a significant proportion of determined cases (68%), anthropogenic causes of morbidity and mortality such as chronic oiling, trauma, and fishery interactions continue to be considerable (~15%). Nearshore species (grebes, loons, surf scoters) were more frequently impacted by harmful algal blooms compared with offshore species (murres, shearwaters). We characterized the demography of several unusual mortality events increasing the understanding of causes behind seabird wrecks in the area, including those affecting phalaropes, puffins, fulmars and others. In addition to routine necropsies, we examined post-litigation samples from three past oil spill events: 1997 Kure (n = 602), 1999 Stuyvesant (n = 334), and the 2001-02 San Mateo Mystery Spill (n= 169, aka Luckenbach). We found demographic differences among Common Murres collected during these spill events related to the season and phenology of this species. Winter spills affected mainly adults (60 to 63%) and late summer spill affected significantly more chick-rearing males (15:1 sex ratio). These results provide important information to determine appropriate mitigation measures for effective wildlife restoration. We also provided the CDFG- Petroleum Chemistry Lab with 109 oiled feather samples to help identify non-point source spills and aid in OSPR’s natural resources damage assessment (NRDA) process.
The goal of this study was to determine trends and sources of chronic oiling and other mortality ... more The goal of this study was to determine trends and sources of chronic oiling and other mortality factors affecting marine birds in central California, provide this information to California Department of Fish and Game Office of Spill Prevention and Response (CDFG-OSPR) to determine the species and populations affected by oil, and to help guide appropriate mitigation and restoration actions. This information is central to CDFG-OSPR’s mission “to provide best achievable protection of California&#39;s natural resources by preventing, preparing for, and responding to spills of oil and other deleterious materials, and through restoring and enhancing affected resources.” Specifically, our objectives were to 1) quantify and document trends in chronic oiling and other mortality factors by conducting necropsies of seabirds collected by beach survey programs, rehabilitation centers, and state and federal resource agencies, 2) identify sources of oil by analyzing oiled feather samples and comparing them to known specimens at the CDFG-OSPR Petroleum Chemistry Lab (PCL), and 3) increase understanding of the population-level affect of oil spills on marine birds by examining post-litigation specimens. Our results indicate chronic oiling is the cause of 1 to 4% of annual mortality of marine birds in central CA. Species groups most affected by chronic oiling were alcids, loons, grebes, cormorants, pelican, procellarids, phalaropes, and gulls; these same species are also those most affected by catastrophic oil spills. We found several other mortality factors which continue to affect CA seabirds, including fishery entanglement, trauma, biotoxins, and to a lesser extent, plastic ingestion. We found that demographic impacts of oiling events depend upon the season in which the oil spill occurs. Winter events such as Luckenbach spills affected first year birds more than adults whereas late summer and fall spills (e.g, Kure, Stuyvesant) affected more adults than expected. These results may be useful in determining population-level impacts of both chronic and catastrophic oiling events in the future and designing appropriate mitigation plans.
Bycatch during fishing activities is one of the greatest threats to many seabird species across t... more Bycatch during fishing activities is one of the greatest threats to many seabird species across the global ocean (Anderson et al., 2011; Croxall et al., 2012; Lewison et al., 2014). While gearand region-specific techniques can be used to reduce or mitigate seabird bycatch (e.g., Gilman, 2011; Løkkeborg, 2011; Melvin et al., 2014), it remains a significant issue for many seabird populations, especially due to their life history characteristics: long-lived, delayed maturity, and low fecundity. Beyond the impact of removing an individual from the population, disproportionate mortality of individuals of a particular age or sex can have complex and significant demographic impacts (Gianuca et al., 2017; Tuck et al., 2015). Therefore, characterizing the demographic composition of bycatch is essential to understanding its impacts. Demographic biases in seabird bycatch have been observed globally, with regional patterns of sex and age class biases indicating frequent male adult bias in subpo...
Oil spills in coastal California are a conservation concern for many seabird species and are amon... more Oil spills in coastal California are a conservation concern for many seabird species and are among the top threats to wintering populations of Aechmophorus grebes. Western Grebes A. occidentalis and Clark’s Grebes A. clarkii are sister taxa that breed in freshwater lakes throughout western North America and predominantly spend the nonbreeding season in the nearshore marine environment, where they are vulnerable to oiling (Storer & Nuechterlein 1992). In California, Western Grebes are one of the main species impacted by oil spills (California Department of Fish and Game [CDFG] 1969a,b; Straughan 1970, 1971; American Trader Trustee Council 2001; Hampton et al. 2003; Carter 2003; CDFG et al. 2004; CDFG & US Fish and Wildlife Service [USFWS] 2008; Humple 2009; Oiled Wildlife Care Network [OWCN] / PRBO Conservation Science unpubl. data). Understanding demographic parameters — such as sex and age ratios — of impacted populations is critical to assessing immediate and potential long-term e...
Microcystin toxin is a known environmental stressor with implications for ecosystem harm througho... more Microcystin toxin is a known environmental stressor with implications for ecosystem harm throughout many inland waterways in California. This purported freshwater toxin has recently emerged in the marine environment in Monterey Bay. Microcystin abundance and frequency, as well as environmental variables that drive toxin production in the Monterey Bay area were examined by deploying Solid Phase Adsorption Toxin Tracking (SPATT) samplers and evaluating water samples for 3 years. Microcystin was found in 15 of 21 monitored sites and was shown to be correlated with anthropogenic nutrient loading. Because it is relevant to identify an indicator organism to better monitor this toxin, uptake and release of microcystin toxin in California mussels (Mytilus californianus), and commercial oysters (Crassostrea sp.) were also examined. To provide environmental relevancy Mytilus sp. were also collected at 4 sites in San Francisco Bay for 6 months and analyzed for microcystin toxin. The results in...
San Francisco Bay (SFB) is a eutrophic estuary that harbors both freshwater and marine toxigenic ... more San Francisco Bay (SFB) is a eutrophic estuary that harbors both freshwater and marine toxigenic organisms that are responsible for harmful algal blooms. While there are few commercial fishery harvests within SFB, recreational and subsistence harvesting for shellfish is common. Coastal shellfish are monitored for domoic acid and paralytic shellfish toxins (PSTs), but within SFB there is no routine monitoring for either toxin. Dinophysis shellfish toxins (DSTs) and freshwater microcystins are also present within SFB, but not routinely monitored. Acute exposure to any of these toxin groups has severe consequences for marine organisms and humans, but chronic exposure to sub-lethal doses, or synergistic effects from multiple toxins, are poorly understood and rarely addressed. This study documents the occurrence of domoic acid and microcystins in SFB from 2011 to 2016, and identifies domoic acid, microcystins, DSTs, and PSTs in marine mussels within SFB in 2012, 2014, and 2015. At least ...
From August through December 2015, beachcast bird survey programs reported increased deposition o... more From August through December 2015, beachcast bird survey programs reported increased deposition of common murres ( Uria aalge) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August-October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n=35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center (NWHC) and harmful algal bloom toxins at the University of California, Santa Cruz and the National Oceanographic and Atmos...
The demographic consequences of oil spills or other mortality events for breeding seabird populat... more The demographic consequences of oil spills or other mortality events for breeding seabird populations depend on the age and sex composition of the affected population. Differential wintering by sex and age classes occurs in many migratory bird species, and can have ...
From August through December 2015, beachcast bird survey programs reported increased deposition o... more From August through December 2015, beachcast bird survey programs reported increased deposition of common murres ( Uria aalge) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August-October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n=35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center (NWHC) and harmful algal bloom toxins at the University of California, Santa Cruz and the National Oceanographic and Atmos...
Domoic acid and saxitoxin in seabirds in the United States between 2007 and 2018, 2021
As harmful algal blooms (HABs) increase in magnitude and duration worldwide, they are becoming an... more As harmful algal blooms (HABs) increase in magnitude and duration worldwide, they are becoming an expanding threat to marine wildlife. Over the past decade, blooms of algae that produce the neurotoxins domoic acid (DA) and saxitoxin (STX) and documented concurrent seabird mortality events have increased bicoastally in the United States. We conducted a retrospective analysis of HAB related mortality events in California, Washington, and Rhode Island between 2007 and 2018 involving 12 species of seabirds, to document the levels, ranges, and patterns of DA and STX in eight sample types (kidney, liver, stomach, intestinal, cloacal, cecal contents, bile, blood) collected from birds during these events. Samples (n = 182) from 83 birds were examined for DA (n = 135) or STX (n = 17) or both toxins simultaneously (n = 30), using ELISA or LCMS at the National Oceanographic and Atmospheric Administration, National Marine Fisheries Service (NOAA-NMFS) Wildlife Algal-toxin Research and Response Network (WARRN-West) or the University of California, Santa Cruz (UCSC). DA or STX was detected in seven of the sample types with STX below the minimum detection limit in blood for the three samples tested. DA was found in 70% and STX was found in 23% of all tested samples. The ranges of detectable levels of DA and STX in all samples were 0.65-681,190.00 ng g − 1 and 2.00-20.95 ng g − 1 , respectively. Cloacal contents from a Pacific loon (Gavia pacifica) collected in 2017 from Ventura County, California, had the highest maximum level of DA for all samples and species tested in this study. The highest level of STX for all samples and species was detected in the bile of a northern fulmar (Fulmarus glacialis) collected in 2018 from San Luis Obispo County, California. DA detections were consistently found in gastrointestinal samples, liver, bile, and kidney, whereas STX detections were most frequently seen in liver and bile samples. Co-occurring HAB toxins (DA and STX) were detected in white-winged scoters (Melanitta deglandi) in 2009, a Brandt's cormorant (Phalacrocorax penicillatus) in 2015, and a northern fulmar and common murre (Uria aalge) in 2018. This article provides DA and STX tissue concentrations and patterns in avian samples and shows the utility of various sample types for the detection of HAB toxins. Future research to understand the pharmacodynamics of these toxins in avian species and to establish lethal doses in various bird species would be beneficial.
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