Contents lists available at ScienceDirect Harmful Algae journal homepage: www.elsevier.com/locate/hal ThreedecadesofCanadianmarineharmfulalgalevents:Phytoplanktonand phycotoxins of concern to human and ecosystem health Cynthia H. McKenzie a, ⁎ ,StephenS.Bates b , Jennifer L. Martin c , Nicola Haigh d , Kimberly L. Howland e ,NancyI.Lewis f , Andrea Locke g , Angelica Peña g , Michel Poulin h , André Rochon i ,WadeA.Rourke j , Michael G. Scarratt k , Michel Starr k ,TerriWells a a Northwest Atlantic Fisheries Centre, Fisheries and Oceans Canada, St. John's, Newfoundland and Labrador, A1C 5X1, Canada b Gulf Fisheries Centre, Fisheries and Oceans Canada, Moncton, New Brunswick E1C 9B6, Canada c St. Andrews Biological Station, Fisheries and Oceans Canada, St. Andrews, New Brunswick E5B 0E4, Canada d Microthalassia Consultants Inc., Nanaimo, British Columbia V9T 1T4, Canada e Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba R3T 2N6, Canada f Biotoxin Metrology, National Research Council Canada, Halifax, Nova Scotia B3H 3Z1, Canada g Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia V8L 4B2, Canada h Research and Collections, Canadian Museum of Nature, Ottawa, Ontario K1P 6P4, Canada i Institut des Sciences de la Mer de Rimouski, Université du Québec à Rimouski, Rimouski, QC G5L 3A1, Canada j Canadian Food Inspection Agency, Dartmouth Laboratory, Dartmouth, Nova Scotia B3B 1Y9, Canada k Maurice Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, Quebec G5H 3Z4, Canada ARTICLEINFO Keywords: Phycotoxin Harmful algal event Saxitoxin Domoic acid Okadaic acid HAEDAT Alexandrium Pseudo-nitzschia Dinophysis Chaetoceros Heterosigma Northeast Pacific Northwest Atlantic Arctic Canada ABSTRACT SpatialandtemporaltrendsofmarineharmfulalgaleventsinCanadaoverthelastthreedecadeswereexamined usingdatafromtheHarmfulAlgalEventDatabase(HAEDAT).Thisdatabasecontainsthemostcompleterecord ofalgalblooms,phycotoxinsandshellfishharvestingareaclosuresinCanadasince1987.This30-yearreviewof 593CanadianHAEDATrecordsfrom1988to2017,togetherwithotherCanadiandataandpublications,shows that recurring harmful algal events have been widespread throughout both the Atlantic and Pacific coastal regions.The367paralyticshellfishtoxin(PST)reportsrevealedannualandfrequentrecurrencethroughoutboth theAtlanticandPacificregions,includingmulti-yearPSTeventsintheBayofFundy,theEstuaryandGulfofSt. LawrenceandtheStraitofGeorgia.The70amnesicshellfishtoxin(AST)recordsrevealednorecognizabletrend, as these events were usually area specific and did not recur annually. The increasing frequency of diarrhetic shellfishtoxin(DST)eventsovertheperiodofthisreview,intotal59records,canbeatleastpartiallyexplained by increased sampling effort. Marine species mortalities caused by harmful algae (including diatoms, dictyo- chophytes, dinoflagellates, and raphidophytes), were a common occurrence in the Pacific region (87 reports), but have been reported much less frequently in the Atlantic region (10 reports). Notable Canadian records containedinHAEDATincludethefirstdetectionworldwideofamnesicshellfishpoisoning(ASP),attributedto the production of domoic acid (an AST) by a diatom (Pseudo-nitzschia multiseries) in Prince Edward Island in 1987.Thefirstprovencaseofdiarrheticshellfishpoisoning(DSP)inCanadaandNorthAmericawasrecordedin 1990, and the first closures of shellfish harvesting due to DST (associated with the presence of Dinophysis nor- vegica)occurredinNovaScotiain1992,followedbyclosuresinNewfoundlandandLabradorin1993.In2008, massmortalitiesoffishes,birdsandmammalsintheSt.LawrenceEstuarywerecausedby Alexandriumcatenella and high levels of PST. During 2015, the Pacific coast experienced a large algal bloom that extended from California to Alaska. It resulted in the closure of several shellfish harvesting areas in British Columbia due to AST, produced by Pseudo-nitzschia australis. Data from the Canadian Arctic coast is not included in HAEDAT. However, because of the emerging importance of climate change and increased vessel traffic in the Arctic, information on the occurrence of harmful algal species (pelagic and sympagic=sea ice-associated) in that re- gionwascompiledfromrelevantliteratureanddata.Theresultssuggestthatthesetaxamaybemorewidespread than previously thought in the Canadian Arctic. Information in HAEDAT was not always robust or complete enough to provide conclusions about temporal trends. Compilation of spatial and temporal information from HAEDAT and other records is nevertheless important for evaluating the potential role of harmful algae as a https://doi.org/10.1016/j.hal.2020.101852 Received18December2019;Receivedinrevisedform5June2020;Accepted7June2020 ⁎ Corresponding author. E-mail address: Cynthia.McKenzie@dfo-mpo.gc.ca (C.H. McKenzie). Harmful Algae xxx (xxxx) xxxx 1568-9883/ Crown Copyright © 2020 Published by Elsevier B.V. All rights reserved. Please cite this article as: Cynthia H. McKenzie, et al., Harmful Algae, https://doi.org/10.1016/j.hal.2020.101852