Global Harmful Algal Blooms


PROJECT TITLE: Addressing industry and global insurance needs: impacts of HABs on fish farms

Type: ICHA19, International Meeting Special Session

Timeframe: ICHA19 meeting, October 10-14, 2021; session on Oct 12, 14:00-16:00 La Paz time

Principal Investigator name, title: Vera Trainer, Keith Davidson

Address: NOAA, SAMS

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Other key persons (name, title and institution): Mark Wells (School of Marine Science, University of Maine, Orono, ME 04469, USA) and Charles Trick (Department of Biology, The University of Saskatchewan, Saskatoon, SK Canada)

Objectives: A new compendium of case studies on the economic impacts of Harmful Algal Blooms (HABs) on wild and recreational fisheries and aquaculture has recently been published by the North Pacific Marine Science Organization (PICES). Based on a co-sponsored PICES and IOC-SCOR GlobalHAB Workshop on Evaluating, Reducing and Mitigating the Cost of Harmful Algal Blooms, this report compiles case studies on the economic impacts of HABs on farmed salmon and other fisheries, with the aim to guide future research and management decisions as to mitigate the risks associated with these natural events.

The report shows that HAB-related losses faced by insurers of aquaculture operations make up to 45% of insurance claims – and they are larger than any storm that insurers have ever faced.

Despite the several research initiatives of the last two decades, the lack of data, appropriate and standardized protocols, and the dearth of peer-reviewed studies hamper efforts to quantify the societal costs of HAB events, which are increasingly frequent, intense, and long-lasting. As of today, most countries have neither conducted economic analyses of HABs nor collected data that can be used to generate reliable quantitative estimates of net economic losses and impacts. As a consequence, it is hard to develop effective strategies to prevent, control and mitigate HAB events.

In this ICHA2021 side session we will be led in a discussion by insurance industry and on-the-ground aquaculture industry representatives to discuss future research directions and how to work together to address:

- impacts of HABs on aquaculture

- risk thresholds

- early warning

- mitigation cost benefits



PROJECT TITLE: Citizen Science Program in the Strait of Georgia, Canada

Scope: Regional

Type: Monitoring

Timeframe: January 2015 to December 2021                                                              

Program manager: Dr. Isobel Pearsall

Address: Pacific Salmon Foundation, 1682-300 West 7th Avenue, Vancouver, BC, V6J 4S6, Canada

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Other key people:

Nicole Frederickson (program coordinator)

Svetlana Esenkulova (harmful algae component)



The goal of the Citizen Science Program in the Strait of Georgia is to collect and disseminate detailed oceanographic data. This program was implemented by the Pacific Salmon Foundation (PSF) with support from the Oceans and Networks Canada (ONC) and Department of Fisheries and Oceans (DFO). The program has been operating since 2015, and was endorsed by the GlobalHAB program in January 2020. Trained members of local communities (referred to as “citizen scientists”) collect information at ~55 defined locations (Fig. 1) on, or as close to, the same day approximately every two weeks between February and October, annually between 2015-2021. At each station, CTDs (conductivity, temperature, depth) are deployed and water samples are taken for nutrient analysis and phytoplankton taxonomy. The scope and coverage of this program are unprecedented; more details about this program and the CitSci dataset, as well as figures showing oceanographic conditions over 2015-2019, are provided in Pawlowicz et al. (2020). Data are stored at

Figure. 1 Map of the Strait of Georgia with CitSci program sampling locations in 2020.

                Different colours represent different patrols.


During six years of observations to date, heavy blooms of potentially harmful blooms were caused by Noctiluca scintillans (Fig. 2, 3), Heterosigma akashiwo, Pseudo-nitzschia spp., Rhizosolenia setigera, Gonyaulax spp., and Dictyocha spp. Investigation of the relationship between environmental factors and bloom dynamics is underway.

Figure. 2 Noctiluca scintillans bloom, Salt Spring Island, May, 2 2018. Photo by Michael Bahrey.


Figure. 3  Cell of Noctiluca scintillans with Chaetoceros spp. in food vacuoles,

                 Citizen Science sample. Photo by Svetlana Esenkulova



Pawlowicz, R., Suzuki, T., Chappel, R., and Esenkulova, S. 2020. Atlas of Oceanographic Conditions in the Strait of Georgia (2015–2019) based on the Pacific Salmon Foundation’s Citizen Science Dataset. Can. Tec. Rep. Hydrogr. Ocean Sci. 3374: vii + 116 p.

Esenkulova, S., Suchy, K., Pawlowicz, R., Costa, M., & Pearsall, I. Harmful algae and oceanographic conditions in the Strait of Georgia, Canada based on citizen science monitoring. Frontiers in Marine Science,1193.    

Annual reports of the harmful algae observations are published in the State of the Pacific Ocean:

Several reports were published in the Harmful Algae News:

  • Esenkulova, S., Pearsall, I., 2019: Citizen Science oceanography in the Strait of Georgia, Canada – an overview of five years operations. Harmful Algae News 63, 12-13.
  • Ecology of Alexandrium spp. in the Strait of Georgia, British Columbia, Canada 2015. Esenkulova, Pearsall, Novak, 2017: Harmful Algae News 56, 7-8.
  • Observations of Heterosigma akashiwo bloom and associated wild salmon lethargic behavior in Cowichan Bay, Canada, 2014. Esenkulova, Luinenburg, Neville, Trudel, 2014.  Harmful Algae News 50, 16-18.

PROJECT TITLE: Unravelling the influence of nutrients and eutrophication on the development of harmful algal blooms in coastal waters 

Acronym: NutriHABs

Time frame: January 2022 - December 2024

Principal Investigator: Rita Domingues,PhD

Address: Centre for Marine and Environmental Research (CIMA), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal

Phone: +351 289 800 900

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Other Key Persons:

Ana Barbosa, PhD, CIMA-University of Algarve

Ana Amorim, PhD, MARE-University of Lisbon

Pedro Reis Costa, Portuguese Institute of Sea and Atmosphere

Helena Galvão, PhD, CIMA-University of Algarve

Alexandra Cravo, PhD, CIMA-University of Algarve



With this project, we expect to contribute to the advance of HAB science, by improving our understanding of how inorganic and organic nutrients and their ratios modulate HAB events and toxin production, by and identifying patterns of HAB development and their association with nutrient status. In addition, we expect to provide a solid scientific basis for the prediction and management of HABs in coastal ecosystems, as understanding the link between different forms of nutrients and the occurrence of HABs and their harmful effects is fundamental for the design and implementation of effective management strategies. To accomplish our goals, we will use the Ria Formosa coastal lagoon and adjacent coastal waters as case study.

The Ria Formosa coastal lagoon (southern Portugal) is a shallow multi-inlet system subjected to multiple anthropogenic stressors. The occurrence of HABs is common in the Ria Formosa, leading to the interdiction of shellfish harvesting that may extend for long periods, affecting human health, and economic and tourism activities. Toxins associated with amnesic, diarrheic, and paralytic shellfish poisoning have already been identified in the Ria Formosa. Despite highly toxic, most of these HABs are low-biomass events; however, in June 2019 a high-biomass bloom caused an extensive red tide in the region, leading not only to bivalve harvesting interdiction, but also to beach closure. The frequency and intensity of HABs in this region has, indeed, been increasing over the years.

The lagoon is subjected to several anthropogenic sources of nutrients, and eutrophication may be a main driver of HABs in this ecosystem.

The main goal of this project is to determine how the availability and utilization of multiple forms of nutrients influence the occurrence of different types of HAB-forming species and their harmful effects in the Ria Formosa coastal lagoon and adjacent coastal waters. Specific goals are:

  1. To observe and describe the relationships between nutrients, other environmental determinants, and HABs in the Ria Formosa coastal lagoon and adjacent coastal waters, throughout two annual cycles.
  2. To establish unialgal cultures of harmful algal species from the Ria Formosa coastal lagoon and adjacent coastal zone.
  3. To evaluate the effect of increased nutrient loads of N (nitrate, ammonium, urea), P and Si, on the growth and toxin production of harmful (and non-harmful) algal species, using natural phytoplankton microcosms.
  4. To evaluate the effect of varying nutrient ratios and nitrogen source (nitrate, ammonium, urea), on the growth and toxin production of harmful (and non-harmful) phytoplankton species, using natural phytoplankton microcosms.
  5. To understand the physiological consequences of excessive nutrients and unbalanced ratios on nutrient uptake and growth kinetics, and toxin production of relevant harmful phytoplankton species.

Our approach will include descriptive field observations and manipulative laboratory experiments, namely a 2-year monitoring in three distinct areas in the Ria Formosa and adjacent coastal areas, nutrient manipulation experiments using natural phytoplankton microcosms, and nutrient uptake experiments using unialgal cultures of relevant harmful species.

PROJECT TITLERolEof Mixing on phytoplankton bloom initiation, maintenance and DIssipation in the Galician RíaS    

Acronym: REMEDIOS  

Timeframe:December 2016-December 2020 

Web site




Principal Investigator: Beatriz Mouriño-Carballido

Address: Edificio Torre CACTI, Planta1ª, Laboratorio 100. Campus de Vigo. Universidade de Vigo, 36310 Vigo, Spain

Phone: +34-986-818788

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Participants: Universidad de Vigo (Spain), Instituto Español de Oceanografía (Spain), Instituto de Investigaciones Marinas-CSIC (Spain), Ifremer, Brest (France), University of Southampton (United Kingdom), SCRIPPS (USA), Linnaeus University (Swedden)


Project summary: High phytoplankton biomass is produced in the Galician Rías (NW Spain) due to fertilization by coastalupwelling and is responsible for the production of ∼250000 t year-1of Mediterranen mussels (Mytilusgalloprovincialis). Mussel aquaculture in Galicia represents 95% of the Spanish and 50% of the European mussel production, respectively. This successful industry is jeopardized every year by toxic phytoplankton blooms. Turbulent mixing is a key process as it controls water renewal time, which in turns determines the rate of exchange of nutrients, organisms and pollutants in the water column. Our current knowledge states that phytoplankton blooms occur when mixing provides the right levels of light and nutrients. However, due to methodological limitations, only very recently we have been able to quantify turbulence in the field. One of the most fascinating implications of this progress is the possibility to revisit classic models of phytoplankton ecology.

In 1953 Sverdrup proposed a simple conservation mass model, which used the depth of the mixed layer to predict the onset of the North Atlantic spring bloom. This model assumed a thoroughly mixed layer where turbulence was strong enough to distribute the phytoplankton cells evenly through the layer. Following trials, either to verify this hypothesis or to use its theoretical background, have generally forgotten this assumption and used the mixed-layer, defined as a layer homogenous in density, as the equivalent of a turbulent or mixing layer. Despite evidence suggesting that vertical mixing controls the annual cycle of biomass and composition of the phytoplankton community in the Galician Rías (NW Spain), its importance has been inferred from hydrographic conditions. So far, a specific study relating mixing and phytoplankton bloom formation is lacking. We propose to use the theoretical framework of the Sverdrup hypothesis to investigate phytoplankton bloom initiation, maintenance and dissipation in NW Spain. Special attention will be devoted to blooms of species from the genera Dinophysisand Pseudo-nitzschia, responsible for lengthy shellfish harvesting closures due to accumulation of diarrhetic (DSP) and amnesic (ASP) shellfish poisoning toxins, respectively, above regulatory levels. Previous studies in this region and in other areas in Western Europe indicate that these species frequently aggregate in “thin layers”. These layers, less than five meters thick and up to several km in horizontal extension, have important implications for the management of mollusc shellfish safety. Despite their socio-economic impact, the frequency of occurrence of thin layers of phytoplankton in the Galician Rías, and the role of mixing conditions in their formation and persistence remains unknown. 


REMEDIOS has a multidisciplinar project combining the expertise of different Galician and international (French and US) collaborations:


  1. Field observations of physical (including microstructure turbulence, cooperation with University of Southampton), chemical and biological variables (including nutrients uptake rates, cooperation with IFREMER; DNA RNA sequencing, Linnaeus University) in the Galician Rías and adjacent shelf using high vertical resolution instruments (including the IFREMER Fine Scale Sampler);
  2. Time series analysis of data collected by monitoring programs
  3. Empirical and numerical modeling (cooperation with SCRIPPS)


The main goal ofinvestigating the role of mixing in phytoplankton bloom formation in the Galician Rías will be pursued through the following specific objectives:


  • Objective 1: Describing theseasonal variability in the sources of turbulence and mixing magnitude;
  • Objective 2: Investigating the role of mixing on resource availability and phytoplankton bloom initiation, maintenance and dissipation;
  • Objective3: Describing the frequency and spatial distribution of thin layers of phytoplankton (TLP), and
  • Objective 4:Investigating the mechanisms responsible for the formation of TLP. 


Microstructure Turbulence Profiler deployed from the Research Vessel Krakhen (UVIGO) at the Ría de Vigo during the REMEDIOS-seasonal study (April 2017)

IFREMER Fine-Scale Sampler deployed from the Research Vessel Margalef (IEO)

at the Ría de Pontevedra during the REMEDIOS-TLP cruise (July 2018).

PROJECT TITLE: International Collaborative Study for the Validation of a HILIC-MS/MS Method for Analysis of Paralytic Shellfish Toxins and Tetrodotoxin in Live Bivalve Molluscs

Scope: Global

Type: Research

Time frame: January 2017 to September 2018

Principal Investigator: Dr Andrew D. Turner

Address: Centre for Environment Fisheries and Aquaculture Science (Cefas)

Tel/Fax: +44 (0)1305 206636 / +44 (0)1305 206601

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Other key persons: Dr Tim Harwood, Cawthron Institute, New Zealand


The aim of this project will be to conduct a Collaborative Study of the LC-MS/MS method for PSP toxins and Tetrodotoxin in shellfish, using a suitable number of international toxin testing laboratories. The work will require active collaboration with organisations worldwide to validate the method, ultimately demonstrating its fitness for purpose for official control testing. The final achievement will involve the delivery of an extensive data set, the publication of the collaborative study and ultimately the delivery of a formally-approved official method of analysis.

The project will be conducted through a collaborative study lead by Dr Andrew Turner at Cefas together in partnership with Dr Tim Harwood at Cawthron Institute. Additional guidance will be provided by Dr James Hungerford, USFDA and Co-chair of AOAC Marine Toxin Task Force and Dr Paul McNabb, marine toxin analysis expert.

Implementation progress and outcomes: 

The collaborative study that led to the PST/TTX analysis by LC-MS/MS known as the "Boundy Method" was completed and published in 2019. It was the result of a successful participation of 21 laboratories from around the world (Europe, Australasia, Asia, North and South America and the Indian sub-continent). The study consisted of the analysis of shellfish sourced from six continents, a wide variety of phytoplankton, toxin profiles and sample toxicities, as well as LC-MS/MS instruments. Quantitative data in 34 separate shellfish tissue samples, comprising multiple blind duplicates enabled the assessment of method reproducibility, repeatability and trueness.

The new validated method (Turner et al., 2020) includes faster turnaround times, greater accuracy and overall cost savings in terms of analyst time when compared to other accredited analytical methods used for monitoring this toxin class in shellfish (e.g., the Lawrence method; AOAC OMA 2005.06). Since the publication of the method, it is being used in New Zealand by the seafood industry and regulatory agency (Ministry for Primary Industries -MPI) for control of PSP toxins in bivalve mollusks and shellfish tissues. Multiple laboratories in Europe have expressed their desire to move to this method if given the opportunity by the EU legislation. The method has also become an essential research tool in recent years for laboratories wishing to conduct more accurate profiling of PSP toxin distributions in a wide range of aquatic organisms.

Cawthron scientists have provided training and informal mentoring and guidance to Analytical Services Tasmania, an Australian laboratory who have implemented the method within their laboratory and now use it for regulatory control purposes. Several informal training courses have been conducted at Cefas, providing background and practical on-the-job training for scientists wishing to learn about use of the method.

Information about the method and the associated validation study can also be found at the Cawthron web side:

Relevant papers: 

Turner, A.D., Dhanji-Rapkova, M., Fong, S.Y.T., Hungerford, J., McNabb, P.S., Boundy, M.J. and Harwood, D.T. (2020). Ultrahigh-performance hydrophilic interaction liquid chromatography with tandem mass spectrometry method for the determination of paralytic shellfish toxins and tetrodotoxin in mussels, oysters, clams, cockles and scallops: collaborative study. J. AOAC International. 103, 533-562,

Ultra-High Performance Hydrophilic Interaction Liquid Chromatography with Tandem Mass Spectrometry Method for the Determination of Paralytic Shellfish Toxins and Tetrodotoxin in Mussels, Oysters, Clams, Cockles and Scallops: Collaborative Study. Final project study report, June 2019. Submitted to EURL, Vigo for assessment and all study participants. Turner, A.D. (Cefas), Boundy, M and Harwood, D.T (Cawthron). Study advisors: Hungerford, J. (USFDA), McNabb, P. (consultant).

Turner, A.D., Boundy, M.J. and Dhanji-Rapkova, M. (2017) Single laboratory validation of a LC-MS/MS method for quantitation of Tetrodotoxins in mussels and oysters. J. AOAC International. 100(5) 1-14

Boundy, M.J., Selwood, A.I., Harwood, D.T., McNabb, P.S. and Turner, A.D. (2015) Development of a sensitive and selective liquid chromatography-mass spectrometry method for high throughput analysis of paralytic shellfish toxins using graphitised carbon solid phase extraction. J. Chrom. A., 1387, 1-12

                                   CEFAS Aquatic Toxins Team. Study coordinator Dr Andy Turner is located front middle

                             Cawthron marine toxin analysts Emilie Burger, Michael Boundy, Dr Tim Harwood (left to right)

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