First Record of Fukuyoa sp. (Gambierdiscoideae) in the Northeastern Region of Términos Lagoon, Campeche, Mexico Fig. 1. Map of sampling stations at Términos Lagoon, Campeche, Mexico. The station where Fukuyoa sp. was found is circled in red. Términos Lagoon is a region of substantial economic relevance due to its fisheries, petroleum activities, and high biodiversity, which includes dolphins, manatees, waterbirds, crocodiles, and jaguars, among other species. Situated in the southern Gulf of Mexico along the coastal zone of Campeche, it is recognized as the second-largest coastal lagoon in Mexico. The system maintains two connections with the Bay of Campeche: the Carmen Inlet to the northwest and the Puerto Real Inlet to the northeast. The Puerto Real inlet is characterized by a significant marine influence, which sustains extensive seagrass meadows. These communities are primarily composed of Thalassia testudinum (turtlegrass), Syringodium filiforme (manatee grass), Halodule wrightii (shoal grass), and Halophila engelmannii (star grass). These meadows provide a specialized ecological niche for diverse microalgal assemblages, including epiphytic and benthic dinoflagellates. Therefore, this study aimed to document the presence of benthic toxic dinoflagellates (BTD) in the Términos Lagoon, Campeche, Mexico. 10 As part of the research project Ecological Characterization of Coastal Environments of Mexico UAM-ICD.CBS, 20232026, a comprehensive sampling campaign was conducted at 27 stations across the Términos Lagoon in May 2024 (Fig. 1). Water samples were collected using a 2.5 L Van Dorn bottle, from which 500 mL subsamples were taken to measure physicochemical parameters specifically salinity, temperature, and pH using a Hanna multiparameter probe. For biological analysis, horizontal tows were performed at each station using a conical net with a 60 μm mesh size; the collected samples were stored in 250 mL bottles and fixed with a 4% formalin solution. In the laboratory, subsamples mounted on glass slides with coverslips were examined under a Zeiss-AxioLab brightfield microscope at 40x magnification. Additionally, Calcofluor White staining was employed to observe thecal plate patterns via epifluorescence microscopy (Zeiss-AxioLab) using the same magnification. Morphological identification of benthic dinoflagellates was performed using the specialized descriptions provided by Hoppenrath et al. (2023) [1]. In the northeastern region of the Términos Lagoon, specifically at the Puerto Real pier (Fig. 1), the presence of a benthic dinoflagellate belonging to the genus Fukuyoa is reported for the first time. Cells (n = 14) present a well-defined ovoid shape that is anteroposteriorly compressed, with a diameter ranging from 4060.6 μm and a transdiameter (width) of 36.151.3 μm (Fig. 2). They exhibit a highly compressed ventral view, a descending cingulum, and a well-defined sulcus. Notably, Fukuyoa sp. was recorded in the water column; this occurrence may be attributed to the environment at the Puerto Real pier zone (E25), which features seagrass meadows dominated by Thalassia testudinum and calcareoussandy sediments, under temperatures ranging from 3132 C, salinities between 3338.9, and shallow depths of 0.51 m. Currently, four species are recognized within the genus Fukuyoa: F. ruetzleri (M.A. Faust, Litaker, Vandersea, Kibler, W.C. Holland & P.A. Tester) F. Gómez, D.X. Qiu, R.M. Lopes & Senjie Lin; F. yasumotoi (M.J. Holmes) F. Gómez, D.X. Qiu, R.M. Lopes & Senjie Lin; F. paulensis F. Gómez, D.J. Qiu, R.M. Lopes & Senjie Lin; and F. koreensis Zhun Li, J.S. Park, N.S. Kang, K.-W. Lee & H.H. Shin [2 4]. Based on the thecal plate arrangement of the cells found in the Términos Lagoon, and following the specific tabulation formula proposed by [2] (Po, 3, 7, 6C, 5, 1p, 2), the specimen morphologically conforms to Fukuyoa paulensis. This preliminary identification is supported by the globular cell shape, cingular displacement, and the distinctive configuration of the apical pore complex (Po) and the 1plate. However, since the smaller cingular and sulcal plates) require further verification and given the well-documented cryptic diversity within this genus, molecular sequencing is strongly recommended to provide a reliable species-level identification for this dinoflagellate. Dinoflagellates belonging to the genus Fukuyoa inhabit benthic and epibenthic environments and are commonly associated with macroalgae, sediments, corals, seagrasses, and occasionally the water column, in tropical coastal waters such as those of the Tér minos Lagoon [2]. Studies conducted HARMFUL ALGAE NEWS NO. 83 / 2026 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 83 June 2026 https://hab.ioc-unesco.org/ Long and Winding Sea-lanes for Fish-Killing Algal Events An ancient idiom dead fish rot (or stink) from the head down possibly attributable to Turkish or Persian fishers but the orig Fig. 2. Programme for the Advanced International Colloquium and Technical Workshop on fish killing marine algae and their effects. blooms. The WG also decided to revise the classic but outdated Cooperative Research Report [2] on HAB effects on mariculture and marine fisheries published in 1992 for Chilean government, through CORFO and cooperation of CREAN-IFOP (reported in HAN 63 [3]) (Fig. 2). The colloquium convenors invited international experts to Puerto Varas, Chile in 2019 to review disciplinary knowledge on all aspects of fish-killing algae and associated mortality events (Fig. 3). A p ins were added during the IPHAB XVII Intersessional (2025-2026), but the total meagre reported ichthyotoxins score (by March 2025) (zero goniodomins, zero prymnesins, one karlotoxin [sterolysin]) has increased dramatically (by February 2026): seven goniodomins, four prymnesins, one karlotoxin, and m (admittedly controversial) explain how toxigenic blooms may directly kill fish in aquaculture operations [e.g., 11]. Access to comprehensive time-series databases on HAB events (HAEDAT, HAIS/ OBIS) has allowed for interpretation of fish-killing events over decades on a regional geographical basis, e Catastrophic marine mass mortalities, shellfish toxicity and human respiratory problems from a Karenia cristata dinoflagellate bloom in South Australia, 20252026 Fig. 1. Satellite chlorophyll image from March 2024 showing widespread offshore diatom blooms in response to a massive upwelling event du from which the species name cristata is derived), and a longer hypocone with the right lobe slightly longer than the left. Scanning electron microscopy revealed that the crest was formed by a slight elevation of the right side of the apical groove. On the dorsal side, the apical groove extended to o Unprecedented bloom of Fibrocapsa japonica on French coasts Fig. 1. Map of the different bays in southern Brittany monitored as part of the REPHY program. Since 1987, the REPHY (French Phytoplankton and Hydrology Monitoring Network in Coastal Waters), operated by IFREMER, has conducted long-term m Fig. 3. Light microscope images of living Fibrocapsa japonica cells. Scale bars = 20 μm. French waters. REPHY data [9] indicate that the previous maximum abundance occurred in 2013 in the Vilaine estuary, reaching 1.9 x 105 cells L1, approximately 25 times lower than values than maximum concentrati First Record of Fukuyoa sp. (Gambierdiscoideae) in the Northeastern Region of Términos Lagoon, Campeche, Mexico Fig. 1. Map of sampling stations at Términos Lagoon, Campeche, Mexico. The station where Fukuyoa sp. was found is circled in red. Términos Lagoon is a region of substantial economic rele Fig. 2. (AB). Fukuyoa sp. in ventral view. (C). Dorsal view. (D). Antapical view showing plates S. d. p., 1, 1. (EF). Ventral view showing plates 1, 1,2, 7, S. d. p., 1,1. (GH). Antapical view showing plates 1p,2,3, 1, 2. Scale bars = 20 μm. in Australia [6] recorded F. paulensis at temperatures of Trophic interactions shape ciguatera risk in a warming ocean Ciguatera is one of the most widespread marine poisonings worldwide, caused by the consumption of fish that bioaccumulate ciguatoxins (CTXs) produced by dinoflagellate species belonging to the genus Gambierdiscus. Its expansion into non-en drivers such as temperature variability and habitat disturbance. Calibration and validation with empirical data on cell densities, toxin concentrations, and ecosystem dynamics will be essential to generate robust predictions. The inclusion of spatial structure and coupling with human health risk mod Red and green waters in southern B rittany (France) in March 2026 linked to a bloom of Mesodinium spp. Fig. 1. Map of reported water discoloration events in southern Brittany (1012 March 2026) based on PHENOMER observations and direct reports. Locations include the Bay of Audierne and the Bay of C Fig. 3. Sentinel-2 satellite image (11 March 2026) showing the spatial extent of the bloom in southern Finistère, with burgundy-red patches indicative of high Mesodinium surface concentrations. are more stable and impart a green coloration. This transformation can occur within minutes, explaining t Fig. 6. Cells of Mesodinium major. 13. Different views of living cells. 46. Representation of pigment dynamics during Mesodinium cell degradation: transition from phycoerythrin-dominated red coloration to chlorophyll-dominated green coloration following cell lysis. All images to scale. accompanied Who turned on the light? First report of extensive bioluminescent blooms of the heterotrophic dinoflagellate Noctiluca scintillans with low abundance of bioluminescent bacteria in the Gulf of Nicoya, Costa Rica Historically, the Gulf of Nicoya has experienced recurrent algal blooms, including events Fig. 2. Dominant dinoflagellate of the Noctiluca scintillans algal bloom around Cedros Island. (A) Bloom of N. scintillans. (B) Ciliate fed on by Noctiluca, Strombidium sp. (C) Culture of bioluminescent bacteria. (D, E) bioluminescence observed at night on Cedros Island and surrounding areas (photog estuaries supporting fisheries, tourism, and biodiversity. Monitoring these processes allows differentiation between benign and harmful blooms and supports the preservation of ecosystem integrity. Ultimately, such phenomena not only expand scientific understanding but also underscore the resilience International Conference on Molluscan Shellfish Safety (ICMSS) Dear colleagues, We wanted to draw your attention to the upcoming International Conference on Molluscan Shellfish Safety (ICMSS), taking place 611 September 2026 at the University of Exeter, UK. Further details, including registration (w DART in action: Scientists launch regional effort against toxic diatoms Scientists from across Asia have come together to tackle the growing threat of toxic diatoms that produce neurotoxin Domoic Acid (DA). On 1718 March 2026, researchers from China, Malaysia, and Singapore gathered in Qingdao, Chin Fig. 2. Kick-off meeting and research presentations. (A) Nancheng Chen, the lead PI, delivers the opening address. (BD) PIs from participating countries presenting their national research plans. (EF) Selected presentations delivered during the workshop. molecular tools can greatly improve our abilit IOC-FAO Intergovernmental Panel on Harmful Algal Blooms (IPHAB) Extraordinary online Session 27 October 2026 and 18th Session (IPHAB-XVIII), 1820 March 2027, FAO, Rome The Intergovernmental Panel on Harmful Algal Blooms (IPHAB) was established in 1992 to strengthen the scientific, managerial, and fi