predatorial protists, viruses, and bacteria (Alexandra Worden). Several plenary talks highlighted insights on HAB management, including emergent management strategies for monitoring, biotoxin detection, and human health risks associated with Ciguatera Poisoning (Marie-Yasmine Dechraoui Bottein); community partnerships in monitoring of HABs and shellfish toxins (Christopher Whitehead); examples about the importance of national networks to share HAB knowledge and promote communication, education and outreach (Ernesto García-Mendoza), and the consequences of eutrophication and extreme events on HABs and implications for salmon farming off the coast of Chile (Jorge Mardones). 1. Taxonomy - Who is out there? A high diversity of benthic and epiphytic dinoflagellate flora in Australian tropical waters was reported, including Coolia tropicalis, C. areolata, Ceratocorys malayensis, Prorocentrum lima and P. sculptile, and also five new or currently undescribed species including one Amphidinium, one Gymnodinium, two Ostreopsis, and one Prorocentrum species (Christopher Bolch). A new species of the genus Gertia was described (Kazuya Takahashi), which is a unique peridinin-containing species in the Kareniaceae. In addition, there were several descriptions of new tropical dinoflagellates including two species of Heterocapsa (Afiqah Hamilton Hanifah), two species of Alexandrium (sub. gen. Gessnerium; Nursyahida Abdullah), a novel Suessiacean dinoflagellate (Wai Mun Lum) and new DNA sequence data for a diversity of gymnodinoid species (Alexis Escarcega). Using cell immunolocalization techniques, cellular compartments that are involved in ciguatoxin (CTX) production and release in Gambierdiscus australes were identified. This finding suggests that the cell endomembrane system is involved in toxin production (Giorgio Honsell). Variations in toxin content and metabolomic profile were described for two genetically similar populations of Gambierdiscus eccentricus with different geographical origins along the coast of Brazil. Toxicity risks associated with G. eccentricus appear higher with warmer, clearer, and less turbulent coastal waters (Luiz Mafra). HARMFUL ALGAE NEWS NO. 69 / 2022 Moreover, CTX was shown to be retained for at least 3.3 months after fish are removed from a CTX source. This should be considered when developing models of CTX cascades between dinoflagellates and resident high sitefidelity fish and has implications for toxin analyses of fish that migrate away from CTX sources for long periods (Clay Bennett). A ciguatera poisoning survey along the west coast of Mexico showed that this illness is poorly documented and understood, particularly among medical professionals. This survey was the first step in developing effective means to inform physicians and the public (Aramis Olivos-Ortiz). Coupling of ecological and epidemiological data showed that the most significant respiratory impacts caused by Ostreopsis take place when blooms enter the late log phase, which is important information for protecting human health (Elisa Berdalet). 2. Distribution and diversity Where are they? There is no doubt about the high diversity and wide spread of HABs and toxins (many presentations) and molecular approaches reveal increasing diversity in HABs and toxin genes, but toxin genes and genotypes are not always related (Cecilio Valadez-Cano, Emma Johansson), and we are still asking ourselves if the frequency of HABs is increasing. A global monitoring metadatabase did reveal regional trends but reported no uniform global trend in HABs and increased occurrence could be linked to enhanced monitoring (Gustaaf Hallegraeff). In some specific cases, such as Dinophysis, a decadal distribution and associated shellfish toxins in the Regional Seas of Europe showed that while some subregions presented an increasing or decreasing trend for some species, no overall trend was detected at the genus level (Philipp Hess). A review of Ciguatera Poisoning (CP) global occurrences and trends was presented, which highlighted some major issues that currently hamper global efforts to capture the true burden of ciguatera. In this case, databases clearly reflect a significant weakness in data entry of CP events and Gambierdiscus/Fukuyoa spp. occurrence records, so data collated from scientific and grey literature are also important to understand global trends. The available time-series data on a limited number of CP endemic to countries/regions revealed that none of the studied areas showed an identical trend (Mireille Chinain). Longer time series on regional HABs were presented as well, which used ancient DNA and akinetes with over >9,000 and > 400 years records of dinoflagellates (Fig. 2) and cyanobacteria, respectively (Linda Armbrecht, Steffaney Wood). 3. Toxins and toxicology What are they making? An expansion of Alexandrium pseudo gonyaulax in Northern European waters was shown, together with the global distribution of other known goniodomin (GD) producers. GD showed conversions and appropriate chromatographic techniques need to be applied in order to avoid artefacts. Preliminary results suggest that GD are not responsible for ichthyotoxicty of GD-producing species (Bernd Krock). A new data dependent LC-HRMS method was presented, which led to the discovery of several gymnodimine fatty acid esters and the detection of new gymnodimines through a backward analysis approach. Also, pinnatoxin G (PnTx-G) was for the first time detected in mussels in Sardinian coastal waters in 2016 (Luciana Tartaglione). The ichthyotoxicity of Chattonella marina was shown to depend on photosynthesis, especially related to the photoreaction stage (Zhuoyun Xu). Results from an experiment where Daphnia magna was exposed to cell free cyanobacterial spent medium from Microcystis aeruginosa highlighted that besides microcystin-LR, other secondary metabolites contribute to a negative impact of this cyanobacterium on D. magna survival and stress response (Gorenka Bojadzija Savic). The phylogeny, lipid composition, pigment signature, ichthyotoxicity and growth of the fish-killing dinoflagellate Heterosigma akashiwo from Chilean Patagonia was highlighted. Further characterization of more Chilean isolates is needed to understand the precise ichthyotoxic mechanisms and environmental drivers that trigger massive bloom events in Chilean Patagonia (Ana Flores). A screening of the ichthyotoxic potency of Karlodinium veneficum strains against the rainbow trout fish gill cell line (RTgill-W1) showed that a 5 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 69 - February 2022 https://hab.ioc-unesco.org/ The 19th (1st Virtual) International Conference on Harmful Algae hosted from Mexico The 19th International Conference on Harmful Algae (19 ICHA), was held in a virtual format for Lobby of the virtual ICHA 2021 costs to attend the meeting. The Conference started with two pre-conference sessions of the Young Investigator Networking Session coordinated by Lorena Durán, Carlos Rodríguez, Philipp Hess, and Harry Nelson. Previously, Lorena Durán and Carlos Rodríguez interviewed o The Mexican scientists comprising the Local Organizing Committee special sessions held live on Zoom that covered breakthrough topics on harmful algae from marine and freshwater environments: HAB Early Warning Systems Session, Impacts of HABs on fish farms: Addressing industry and global insurance n Scientific Highlights of the 19th International Conference on Harmful Algae Summarizing all of the science from a conference is a huge and perhaps impossible task, but once done, it can serve as a reference for the future. We had five exciting and intensive virtual conference days where all the late predatorial protists, viruses, and bacteria (Alexandra Worden). Several plenary talks highlighted insights on HAB management, including emergent management strategies for monitoring, biotoxin detection, and human health risks associated with Ciguatera Poisoning (Marie-Yasmine Dechraoui Bottein); com Fig. 2. Long-term history of HABs off Eastern Tasmania, Australia, using sedimentary DNA (courtesy of Linda Armbrecht) French Mediterranean and a French Atlantic K. veneficum strain induced over 50% loss of cell viability. A high level of intra-specific variability of ichthyotoxic activity was obse pacificum and Durusdinium trenchii) to be successfully frozen and revived with high viability (Joseph Kihika). This highlights the potential to have a microalgae diversity bank in the future. Several presentations were focused on the intimate association between hosts and their microbiomes (Chri Fig. 4. Example from a weekly HAB bulletin reporting HAB events along the Irish coast (courtesy of Dave Clarke) harvested along the coast. Analysis of seawater and oyster samples confirmed high levels of PSP toxins (Margarita Fernández-Tejedor). The design, implementation, and contents of HAB bulle for lake ecosystem services and selection of environmental measures together with local farmers, which may reduce overall costs (Claudia Wiegand). A special session on the new WHO book Toxic cyanobacteria in water provided advice and guidelines for the management of freshwater cyanobacterial blooms, ISSHA's Corner The International Society for the Study of Harmful Algae (ISSHA) convened the 19th (1st Digital) International Conference on Harmful Algae (19 ICHA), held in La Paz, México, from 10th to 15th October 2021. The ISSHA Council had monthly meetings on-line between May and October to plan molecular probes targeting HAB species (including their different life cycle stages), difficult to identify with conventional microscopy methods. More information about Lindas biography and publications can be found here. Nomination letter of Linda Medlin to the ISSHA Council There are many, many re waters of the South China Sea, a marginal sea of the Western Pacific (Teng et al. 2013, 2014). Sing Tung Teng has demonstrated his training and dissemination skills by introducing a taxonomic grouping of Pseudo-nitzschia based on frustule morphology, which eventually developed into an interactive ke from some species of Rhodophyta to the cultures significantly enhanced the growth of the two Gambierdiscus species that occur in Japan. He is now starting an investigation to clarify the effect of bacteria on Gambierdiscus growth in an attempt to elucidate the growth characteristics of Gambierdiscus ISSHA President goodbye Dear ISSHA members: As many of you know, at the general glection held prior to the International Conference on Harmful Algae (ICHA2021) from 11-15 October 2021 (La Paz, Mexico), I stepped down as the president of the International Society for the Study of Harmful Algae (ISSHA UNESCO Taxonomic Reference List of Harmful Micro Algae Editors Workshop 2021 On November 18-19th 2021, the nine thematic editors responsible for the UNESCO Taxonomic Reference List of Harmful Micro Algae and Henrik Enevoldsen from IOC-UNESCO gathered together in a hybrid format workshop, to discuss Book Review: A Catalogue of Phytoplankton from the Mexican CentralPacific (in Spanish) Authors: Hernández-Becerril, D.U., Barón-Campis, S.A., Ceballos-Corona, J.G.A., Alonso-Rodríguez, R., RinconesReyes, K.M., Becerra-Reynoso, R.T. & Arce-Rocha, G. 2021. Catálogo de fitoplancton del Pacífico central Forthcoming Events 2022 UN Ocean Conference GLOBAL ONLINE STAKEHOLDER CONSULTATION Inputs to concept papers of interactive dialogues Contribute your inputs to the concept papers of the interactive dialogues for the 2022 UN Ocean Conference! (see back page) Deadline: 21 February 2022 Contribute your GlobalHAB symposium on automated in situ observations of plankton Aims and background Harmful Algal Blooms (HABs) are affecting aquatic ecosystems and human societies. Biotoxin-producing HABs species and species causing fish mortalities are problems for aquaculture, fisheries and also for tourism. H www.neiwpcc.org/events/ushab11 #USHAB2022 For logo contest rules, please visit our conference website. We are pleased to announce that the 11th U.S. Symposium on Harmful Algae will be held on October 23-28, 2022 in Albany, New York, at the Hilton Albany. Local coordination is being led by NEIWPCC, Eds-in-chief Beatriz Reguera, IEO (CSIC), Vigo, Spain Eileen Bresnan, Marine Scotland, UK Regional Editors Caribbean: Ernesto Mancera jemancerap@unal.edu.co Atlantic Europe: Maud Lemoine Maud.Lemoine@ifremer.fr Mediterranean Sea: Adriana Zingone zingone@szn.it India: K.B. Padmakumar kbpadmakumar