Yellow-green tides could become a recurrent event along the Ligurian coast (Italy) Fig. 1. A) Sestri Levante and Baia del Silenzio bay, characterized by shallow water and mixed rocky-sandy seabed containing the macrophyte, Posidonia oceanica (dark grey) and carpet-like matte (light grey) habitat. B) Liguria Region and the sites (yellow stars) included in the harmful algal bloom monitoring program Fig. 2. Cell densities of Alexandrium taylorii and Pyramimonas spp. and seawater temperature (oC) from Sestri Levante Bay (Genoa, Italy), summer 2019. Alexandrium blooms are becoming an increasing phenomenon in the Mediterranean Sea. These blooms mainly occur in semi-enclosed areas exposed to anthropogenic pressures from aquaculture, tourism and nutrient enrichment [1]. Alexandrium taylorii Balech is a potentially toxic dinoflagellate that causes 10 a yellow-green water discoloration. Some published studies suggest that four western Mediterranean areas are affected by blooms of this species: the Catalan Coast (NE Spain), the Balearic Islands, northern Sardinia and Sicily (Vulcano Island, Italy) [2]. During the summer of 2019, blooms of A. taylorii impacted the eastern Ligurian coast (north-western Italy) causing significant long lasting yellow-green water discolorations. These were especially noticeable along the Sestri Levante area (Fig. 1) causing concern from both the tourism industry and local authorities. The first bloom of A. taylorii in Ligurian coastal waters, with a maximum density of 1.4 x106 cells L-1, was reported by the Regional Environmental Protection Agency of Liguria (ARPAL) in the summer of 2010. Although samples from this bloom did not test positive for algal toxins, since then ARPAL have increased monitoring efforts in compliance with the European Bathing Water Directive. Every year, from June to September, ARPAL collects and analyses samples of both seawater and macrophytes according to the Italian monitoring protocols for harmful algal blooms [3]. Significant A. taylorii blooms have been reported during the summers of 2012 (up to 6.0 x 104 cells L-1), 2013 (> 3.0 x 106 cells L-1), 2016 (5.0 x 104 cells L-1) and 2019 (> 3.0 x 105 cells L-1) (Fig.2). This suggests an increased frequency in the occurrence of A. taylorii blooms, especially on the eastern Ligurian coast. These blooms often co-occur with high cell densities of Pyramimonas spp., a nano-phytoplankton taxon belonging to the Chlorophyta group that may cause bright green tides. During the summer of 2019, additional water discoloration events at different sites along the eastern Ligurian coast (e.g. Paraggi, S. Margherita Ligure) with more than 6.5 x 104 cells L-1 were recorded by the local sanitary agency and Genoa University. A study was performed isolating that causative organisms into laboratory culture to confirm species identification by molecular analysis, thecal plate morphology using epifluorescence microscopy, and toxin analysis. Unfortunately, it was not possible to maintain the algal culture for the toxin characterization of the strain. In general, A. taylorii is considered a high biomass HAB species that negatively impacts the use of coastal waters for recreational purposes. This species also has the potential to produce Paralytic Shellfish Toxins (PSTs) and other unknown harmful compounds [4]. To date, there have never Continued on page 12 HARMFUL ALGAE NEWS NO. 64 / 2020 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 64 - June 2020 www.ioc-unesco.org/hab The IOC Taxonomic Reference List of Harmful Microalgae The creation of the IOC Taxonomic Reference List of Harmful Microalgae was first discussed 23 years ago at the Fourth Session of the ever the information presented in publications is not always easy to interpret. Toxic blooms often contain several species and studies on individual species are therefore required to determine the species responsible for the toxin production. In addition, species are sometimes difficult to identify considered this to be identical to the previously described P. mexicanum [9]. This statement makes little sense, and Loeblich et al in fact do not mention P. mexicanum in their article. Faust [8] illustrated material which resembled P. rhathymum using the radical arrangement of some of the trichocys Massive salmon mortalities during a Chrysochromulina leadbeateri bloom in Northern Norway From mid May to mid June 2019, fish farmers along the coast of Nordland and Troms, northern Norway, experienced sudden mortalities of caged salmon [1] (Fig. 1). These mortalities were assumed to be due to a blo Fish kill in numbers [2] 13 000 ton fish 7.5 mill salmon 80 mill EUR 14 companies Fig. 2. Map of Norway showing the area where the Chrysochromulina leadbeateri bloom occurred causing massive fish kills in May-June 2019 References 1. Fiskeridirektoratet 2019. https:// www.fiskeridir.no/Akvakult Mass mortality of marine invertebrates associated with the presence of yessotoxins in northern Chile Fig. 1. Map of the study area showing A) Chilean coast; B) Pabellón de Pica, Tarapacá Region C) Bahía Inglesa, Atacama Region; D) Puerto Aldea, Coquimbo Region During the austral summer of 2019, ma research is needed to determine the mechanism of action and the toxin effects on tissues and cells of the main affected species. Finally, there is a need to establish an educational plan to protect the public and avoid the consumption and commercialization of potentially toxic marine invertebrates. First Report of Heterocapsa minima (Dinophyceae) from Aotearoa/ New Zealand Small planktonic armoured dinoflagellates within the genus Heterocapsa are currently represented by 20 species with some having a world-wide distribution [1-2]. Blooms of some Heterocapsa species have been associated with fi Fig. 2. Maximum likelihood (ML) molecular phylogenetic tree of Heterocapsa minima and H. steinii strains isolated from coastal areas of New Zealand based on the LSU rDNA D1/ D2 sequences (20 sequences, 700 positions). The alignment site corresponded to the 69768 bp site of a sequence from H. steinii Yellow-green tides could become a recurrent event along the Ligurian coast (Italy) Fig. 1. A) Sestri Levante and Baia del Silenzio bay, characterized by shallow water and mixed rocky-sandy seabed containing the macrophyte, Posidonia oceanica (dark grey) and carpet-like matte (light grey) habitat. B First report of a high biomass bloom of Peridinium quadridentatum (F. Stein) Gert Hansen from the tropical Cochin estuary SW coast of India Fig. 1. Map showing the area of P. quadridentatum bloom in Cochin estuary, southwest coast of India Peridinium quadridentatum (F. Stein) Gert Hansen is a cos Table 1. Physico-chemical parameters of P. quadridentatum bloom area in Cochin Estuary Parameters Water Temperature (oC) Salinity (psu) Dissolved Oxygen (ml L-1) Nitrate (μmol L-1) Silicate (μmol L-1) Phosphate (μmol L-1) Chlorophyll a (mg m-3) 28 20 2.01 10.6 23.3 1.3 27.5 higher turbidity, lowe Are mesophotic seamounts reservoirs for potentially toxic dinoflagellates associated with Ciguatera poisoning? A case study from the SW Indian ocean (expédition La Pérouse, 2019) Fig. 1. Location map of La Pérouse seamount off La Réunion. In the western Indian Ocean, a Ciguatera Fish Poisoning (CF Using Machine Learning to Observe Abundance Patterns of the Dino flagellate Noctiluca scintillans in the Western English Channel Noctiluca scintillans is a Harmful Algal Bloom (HAB) species with a wide geographic distribution. It frequently blooms and causes negative impacts on marine ecosystems [1] References 1. Sarma VVSS et al 2019. Mar Pollut Bull 138: 428-436 2. Faust MA & RA Gulledge 2002. Contributions for the US National Herbarium 42: 1-144 3. Graham MD et al 2018. Limnol Oceanogr-Meth 16: 669-679 Author Christian Bamber, The Marine Biological Association, Citadel Hill, Plymouth PL1 2PB International validation and recognition of method for paralytic shellfish toxins in bivalve molluscs Food safety scientists from Cefas (UK) and Cawthron Institute (New Zealand) have led an international study over the past four years to gain international recognition for a new method to quantify pa Aotearoa/New Zealands nationally significant Cawthron Institute Culture Collection of Microalgae (CICCM) The CICCM is critical to international research projects and the 500 isolates of microalgae and cyanobacteria in the collection have been sourced from oceans, lakes and rivers in New Zealand, the The 11th EASTHAB Symposium and 4th Philippine HAB Conference The 11th EASTHAB Symposium and 4th Philippine HAB Conference were held back-to-back from December 11 13, 2019 at the Microtel Hotel, Puerto Princesa, Palawan, the Philippines. The theme was Advances in Harmful Algal Bloom Research, Monito Fig. 1. Participants in the 11th EASTHAB Symposium/4th Philippine HAB Conference Fig. 2. Department of Science and Technology secretary Fortunato dela Peña with the keynote, plenary speakers and local organizing committee leads. Left to right: Dr. Ichiro Imai, representative of the Vice Mayor of Pu The ICES-IOC Working Group on Harmful Algal Bloom Dynamics 2020 Meeting The International Council for the Exploration of the Sea (ICES) and the Intergovernmental Oceanographic Commission of UNESCO (IOC) have collaborated closely for 26 years, stimulating research on HAB population dynamics and monit Fig. 2. Shared day between ICES-IOC WGHABD, ICES-IOC WGBOSV and ICES WGITMO ences using molecular methods as well as results from studies in Arctic areas. These studies presented data on HAB and invasive non-native species present in Arctic waters. A USA study focused on the distribution, community Typical benthic habitat with macroalgae and limestone rubble observed at ~ 60m depth on La Pérouse seamount, Indian Ocean (Photo courtesy of L. Ballesta). Eds-in-chief Beatriz Reguera, IEO, Vigo, Spain Eilen Bresnan, Marine Scotland, UK Regional Editors Caribbean: Ernesto Mancera jemancerap@unal.e