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Dave Clarke
Marine Scotland Marine Laboratory, Aberdeen, AB11 9DB, U.K.

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Journal article
Published: 12 February 2021 in Harmful Algae
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The IOC-ICES-PICES Harmful Algal Event Database (HAEDAT) was used to describe the diversity and spatiotemporal distribution of harmful algal events along the Atlantic margin of Europe from 1987 - 2018. The majority of events recorded are caused by Diarrhetic Shellfish Toxins (DSTs). These events are recorded annually over a wide geographic area from southern Spain to northern Scotland and Iceland, and are responsible for annual closures of many shellfish harvesting areas. The dominant causative dinoflagellates, members of the morphospecies ‘Dinophysis acuminata complex’ and D. acuta, are common in the waters of the majority of countries affected. There are regional differences in the causative species associated with PST events; the coasts of Spain and Portugal with the dinoflagellates Alexandrium minutum and Gymnodinium catenatum, north west France/south west England/south Ireland with A. minutum, and Scotland/Faroe Islands/Iceland with A. catenella. This can influence the duration and spatial scale of PST events as well as the toxicity of shellfish. The diatom Pseudo-nitzschia australis is the most widespread Domoic Acid (DA) producer, with records coming from Spain, Portugal, France, Ireland and the UK. Amnesic Shellfish Toxins (ASTs) have caused prolonged closures for the scallop fishing industry due to the slow depuration rate of DA. Amendments to EU shellfish hygiene regulations introduced between 2002 and 2005 facilitated end-product testing and sale of adductor muscle. This reduced the impact of ASTs on the scallop fishing industry and thus the number of recorded HAEDAT events. Azaspiracids (AZAs) are the most recent toxin group responsible for events to be characterised in the ICES area. Events associated with AZAs have a discrete distribution with the majority recorded along the west coast of Ireland. Ciguatera Poisoning (CP) has been an emerging issue in the Canary Islands and Madeira since 2004. The majority of aquaculture and wild fish mortality events are associated with blooms of the dinoflagellate Karenia mikimotoi and raphidophyte Heterosigma akashiwo. Such fish killing events occur infrequently yet can cause significant mortalities. Interannual variability was observed in the annual number of HAEDAT areas with events associated with individual shellfish toxin groups. HABs represent a continued risk for the aquaculture industry along the Atlantic margin of Europe and should be accounted for when considering expansion of the industry or operational shifts to offshore areas.

ACS Style

Eileen Bresnan; Fabiola Arévalo; Catherine Belin; Maria A.C. Branco; Allan D. Cembella; Dave Clarke; Jorge Correa; Keith Davidson; Monika Dhanji-Rapkova; Raul Fernández Lozano; Margarita Fernández-Tejedor; Hafsteinn Guðfinnsson; David Jaén Carbonell; Aitor Laza-Martinez; Maud Lemoine; Adam M. Lewis; Luz Mamán Menéndez; Benjamin H. Maskrey; April McKinney; Yolanda Pazos; Marta Revilla; Raffaele Siano; Alexandra Silva; Sarah Swan; Andrew D. Turner; Laura Schweibold; Pieter Provoost; Henrik Enevoldsen. Diversity and regional distribution of harmful algal events along the Atlantic margin of Europe. Harmful Algae 2021, 102, 101976 .

AMA Style

Eileen Bresnan, Fabiola Arévalo, Catherine Belin, Maria A.C. Branco, Allan D. Cembella, Dave Clarke, Jorge Correa, Keith Davidson, Monika Dhanji-Rapkova, Raul Fernández Lozano, Margarita Fernández-Tejedor, Hafsteinn Guðfinnsson, David Jaén Carbonell, Aitor Laza-Martinez, Maud Lemoine, Adam M. Lewis, Luz Mamán Menéndez, Benjamin H. Maskrey, April McKinney, Yolanda Pazos, Marta Revilla, Raffaele Siano, Alexandra Silva, Sarah Swan, Andrew D. Turner, Laura Schweibold, Pieter Provoost, Henrik Enevoldsen. Diversity and regional distribution of harmful algal events along the Atlantic margin of Europe. Harmful Algae. 2021; 102 ():101976.

Chicago/Turabian Style

Eileen Bresnan; Fabiola Arévalo; Catherine Belin; Maria A.C. Branco; Allan D. Cembella; Dave Clarke; Jorge Correa; Keith Davidson; Monika Dhanji-Rapkova; Raul Fernández Lozano; Margarita Fernández-Tejedor; Hafsteinn Guðfinnsson; David Jaén Carbonell; Aitor Laza-Martinez; Maud Lemoine; Adam M. Lewis; Luz Mamán Menéndez; Benjamin H. Maskrey; April McKinney; Yolanda Pazos; Marta Revilla; Raffaele Siano; Alexandra Silva; Sarah Swan; Andrew D. Turner; Laura Schweibold; Pieter Provoost; Henrik Enevoldsen. 2021. "Diversity and regional distribution of harmful algal events along the Atlantic margin of Europe." Harmful Algae 102, no. : 101976.

Journal article
Published: 08 January 2021 in Microorganisms
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Azaspiracids (AZA) are a group of lipophilic toxins, which are produced by a few species of the marine nanoplanktonic dinoflagellates Azadinium and Amphidoma (Amphidomataceae). A survey was conducted in 2018 to increase knowledge on the diversity and distribution of amphidomatacean species and their toxins in Irish and North Sea waters (North Atlantic). We here present a detailed morphological, phylogenetic, and toxinological characterization of 82 new strains representing the potential AZA producers Azadinium spinosum and Amphidoma languida. A total of ten new strains of Am. languida were obtained from the North Sea, and all conformed in terms of morphology and toxin profile (AZA-38 and-39) with previous records from the area. Within 72 strains assigned to Az. spinosum there were strains of two distinct ribotypes (A and B) which consistently differed in their toxin profile (dominated by AZA-1 and -2 in ribotype A, and by AZA-11 and -51 in ribotype B strains). Five strains conformed in morphology with Az. spinosum, but no AZA could be detected in these strains. Moreover, they revealed significant nucleotide differences compared to known Az. spinosum sequences and clustered apart from all other Az. spinosum strains within the phylogenetic tree, and therefore were provisionally designated as Az. cf. spinosum. These Az. cf. spinosum strains without detectable AZA were shown not to cause amplification in the species-specific qPCR assay developed to detect and quantify Az. spinosum. As shown here for the first time, AZA profiles differed between strains of Az. spinosum ribotype A in the presence/absence of AZA-1, AZA-2, and/or AZA-33, with the majority of strains having all three AZA congeners, and others having only AZA-1, AZA-1 and AZA-2, or AZA-1 and AZA-33. In contrast, no AZA profile variability was observed in ribotype B strains. Multiple AZA analyses of a period of up to 18 months showed that toxin profiles (including absence of AZA for Az. cf. spinosum strains) were consistent and stable over time. Total AZA cell quotas were highly variable both among and within strains, with quotas ranging from 0.1 to 63 fg AZA cell−1. Cell quota variability of single AZA compounds for Az. spinosum strains could be as high as 330-fold, but the underlying causes for the extraordinary large variability of AZA cell quota is poorly understood.

ACS Style

Urban Tillmann; Stephan Wietkamp; Haifeng Gu; Bernd Krock; Rafael Salas; Dave Clarke. Multiple New Strains of Amphidomataceae (Dinophyceae) from the North Atlantic Revealed a High Toxin Profile Variability of Azadinium spinosum and a New Non-Toxigenic Az. cf. spinosum. Microorganisms 2021, 9, 134 .

AMA Style

Urban Tillmann, Stephan Wietkamp, Haifeng Gu, Bernd Krock, Rafael Salas, Dave Clarke. Multiple New Strains of Amphidomataceae (Dinophyceae) from the North Atlantic Revealed a High Toxin Profile Variability of Azadinium spinosum and a New Non-Toxigenic Az. cf. spinosum. Microorganisms. 2021; 9 (1):134.

Chicago/Turabian Style

Urban Tillmann; Stephan Wietkamp; Haifeng Gu; Bernd Krock; Rafael Salas; Dave Clarke. 2021. "Multiple New Strains of Amphidomataceae (Dinophyceae) from the North Atlantic Revealed a High Toxin Profile Variability of Azadinium spinosum and a New Non-Toxigenic Az. cf. spinosum." Microorganisms 9, no. 1: 134.

Research article
Published: 04 January 2021 in Phycological Research
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Shellfish contamination with azaspiracids (AZA), which are lipophilic marine biotoxins produced by marine dinoflagellates, is a major and recurrent problem for the Irish shellfish industry. AZA are produced by certain species of Amphidomataceae, but the species diversity of this group of microalgae in Irish waters is poorly known. Here we present a morphological and molecular characterization of multiple new strains of non‐toxigenic Azadinium isolated on an oceanographic survey in 2018. A lack of AZA production for all strains presented here was demonstrated by LC‐MS/MS analysis. One strain of Azadinium caudatum var. margalefii (first strain for the area) confirmed non‐toxigenicity of Atlantic populations of this species. One strain designated as Azadinium cf. zhuanum was similar to Az. zhuanum described from China but differed from the type strain in nucleus position, by the dominant number of apical plates, and by significant differences in rRNA gene sequences. Finally, two new non‐toxigenic Azadinium species are described from the North East Atlantic: Azadinium galwayense sp. nov. and Azadinium perfusorium sp. nov. Azadinium galwayense differed from other Azadinium by a characteristic combination regarding presence and location of the ventral pore (vp; on the right side of the pore plate), of a pyrenoid (located in the episome), and by a pentagonal shape of the median anterior intercalary plate 2a, and lack of contact between plates 1″ and 1a. Azadinium perfusorium shared the same vp position as Az. galwayense and differed by a characteristic combination of a pyrenoid located in the hyposome, a tetragonal shape of plate 2a, and a relatively large size of the two lateral anterior intercalary plates. Molecular phylogeny confirmed the distinctiveness of these two new species and their placement in Azadinium. The present findings significantly increased knowledge on the diversity of Azadinium species in the North East Atlantic.

ACS Style

Rafael Salas; Urban Tillmann; Haifeng Gu; Stephan Wietkamp; Bernd Krock; Dave Clarke. Morphological and molecular characterization of multiple new Azadinium strains revealed a high diversity of non‐toxigenic species of Amphidomataceae (Dinophyceae ) including two new Azadinium species in Irish waters, North East Atlantic. Phycological Research 2021, 1 .

AMA Style

Rafael Salas, Urban Tillmann, Haifeng Gu, Stephan Wietkamp, Bernd Krock, Dave Clarke. Morphological and molecular characterization of multiple new Azadinium strains revealed a high diversity of non‐toxigenic species of Amphidomataceae (Dinophyceae ) including two new Azadinium species in Irish waters, North East Atlantic. Phycological Research. 2021; ():1.

Chicago/Turabian Style

Rafael Salas; Urban Tillmann; Haifeng Gu; Stephan Wietkamp; Bernd Krock; Dave Clarke. 2021. "Morphological and molecular characterization of multiple new Azadinium strains revealed a high diversity of non‐toxigenic species of Amphidomataceae (Dinophyceae ) including two new Azadinium species in Irish waters, North East Atlantic." Phycological Research , no. : 1.

Review
Published: 22 January 2019 in Toxins
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The purpose of this work is to review all the historical monitoring data gathered by the Marine Institute, the national reference laboratory for marine biotoxins in Ireland, including all the biological and chemical data from 2005 to 2017, in relation to diarrheic shellfish poisoning (DSP) toxicity in shellfish production. The data reviewed comprises over 25,595 water samples, which were preserved in Lugol’s iodine and analysed for the abundance and composition of marine microalgae by light microscopy, and 18,166 records of shellfish flesh samples, which were analysed using LC-MS/MS for the presence and concentration of the compounds okadaic acid (OA), dinophysistoxins-1 (DTX-1), dinophysistoxins-2 (DTX-2) and their hydrolysed esters, as well as pectenotoxins (PTXs). The results of this review suggest that DSP toxicity events around the coast of Ireland occur annually. According to the data reviewed, there has not been an increase in the periodicity or intensity of such events during the study period. Although the diversity of the Dinophysis species on the coast of Ireland is large, with 10 species recorded, the two main species associated with DSP events in Ireland are D. acuta and D. acuminata. Moreover, the main toxic compounds associated with these species are OA and DTX-2, but concentrations of the hydrolysed esters are generally found in higher amounts than the parent compounds in the shellfish samples. When D. acuta is dominant in the water samples, the DSP toxicity increases in intensity, and DTX-2 becomes the prevalent toxin. Pectenotoxins have only been analysed and reported since 2012, and these compounds had not been associated with toxic events in Ireland; however, in 2014, concentrations of these compounds were quantitated for the first time, and the data suggest that this toxic event was associated with an unusually high number of observations of D. tripos that year. The areas of the country most affected by DSP outbreaks are those engaging in long-line mussel (Mytilus edulis) aquaculture.

ACS Style

Rafael Salas; Dave Clarke. Review of DSP Toxicity in Ireland: Long-Term Trend Impacts, Biodiversity and Toxin Profiles from a Monitoring Perspective. Toxins 2019, 11, 61 .

AMA Style

Rafael Salas, Dave Clarke. Review of DSP Toxicity in Ireland: Long-Term Trend Impacts, Biodiversity and Toxin Profiles from a Monitoring Perspective. Toxins. 2019; 11 (2):61.

Chicago/Turabian Style

Rafael Salas; Dave Clarke. 2019. "Review of DSP Toxicity in Ireland: Long-Term Trend Impacts, Biodiversity and Toxin Profiles from a Monitoring Perspective." Toxins 11, no. 2: 61.

Journal article
Published: 01 November 2017 in Harmful Algae
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Fjordic coastlines provide an ideal protected environment for both finfish and shellfish aquaculture operations. This study reports the results of a cruise to the Scottish Clyde Sea, and associated fjordic sea lochs, that coincided with blooms of the diarrhetic shellfish toxin producing dinoflagellate Dinophysis acuta and the diatom genus Chaetoceros, that can generate finfish mortalities. Unusually, D. acuta reached one order of magnitude higher cell abundance in the water column (2840cellsL) than the more common Dinophysis acuminata (200cellsL) and was linked with elevated shellfish toxicity (maximum 601±237μg OA eq/kg shellfish flesh) which caused shellfish harvesting closures in the region. Significant correlations between D. acuta abundance and that of Mesodinium rubrum were also observed across the cruise transect potentially supporting bloom formation of the mixotrophic D. acuta. Significant spatial variability in phytoplankton that was related to physical characteristics of the water column was observed, with a temperature-driven frontal region at the mouth of Loch Fyne being important in the development of the D. acuta, but not the Chaetoceros bloom. The front also provided important protection to the aquaculture located within the loch, with neither of the blooms encroaching within it. Analysis based on a particle-tracking model confirms the importance of the front to cell transport and shows significant inter-annual differences in advection within the region, that are important to the harmful algal bloom risk therein.

ACS Style

Ruth F. Paterson; Sharon McNeill; Elaine Mitchell; Thomas Adams; Sarah C. Swan; Dave Clarke; Peter I. Miller; Eileen Bresnan; Keith Davidson. Environmental control of harmful dinoflagellates and diatoms in a fjordic system. Harmful Algae 2017, 69, 1 -17.

AMA Style

Ruth F. Paterson, Sharon McNeill, Elaine Mitchell, Thomas Adams, Sarah C. Swan, Dave Clarke, Peter I. Miller, Eileen Bresnan, Keith Davidson. Environmental control of harmful dinoflagellates and diatoms in a fjordic system. Harmful Algae. 2017; 69 ():1-17.

Chicago/Turabian Style

Ruth F. Paterson; Sharon McNeill; Elaine Mitchell; Thomas Adams; Sarah C. Swan; Dave Clarke; Peter I. Miller; Eileen Bresnan; Keith Davidson. 2017. "Environmental control of harmful dinoflagellates and diatoms in a fjordic system." Harmful Algae 69, no. : 1-17.