Spatial Temporal Expansion of Harmful Algal Blooms in Chile: A Review of 65 Years Records

Harmful Algal Blooms (HABs) have been classified depending on the causative organism and its impacts: non-toxic HAB (microalgae capable of affecting tourism causing oxygen deficiency, which generates mortality marine organisms), toxic transferring toxins to food chain), ichthyotoxic generating mechanical damage in fish). HABs represent a worldwide problem apparently increased frequency, intensity, geographic distribution at different latitudes. This review details occurrence events Southeast Pacific, Chile, over 65-year period, analysing two three types described: HABs. For this, we conducted from many scientific sources written press social media, that mentioned country. In microalgae involved are dinoflagellate (52%), diatoms (33%) silicoflagellate (10%), with total 41 species and/or genera described literature. A 501 were recorded Chile between 1956 2021, where 240 (47.9%), 238 (47.5%), 14 (2.7%), 8 (1.5%) 1 (0.2%) event caused by diatoms, dinoflagellate, silicoflagellate, raphidophycean haptophyte, respectively. An apparent increase frequency is observed since first record 1956, maximum 46 during years 2017 2019. The highest incidence fish group haptophyte (23 events), 10 mortalities salmon an rate 43.4%. Unlike what associated these groups less frequent, but hold much higher rate. During last 65 years, HAB’s extent shows trend south-to-north. However, identification closely linked areas country’s aquaculture located and, therefore, it could be biased. turn, greater monitoring effort after major (e.g., 2016 event). On other hand, also recognized lack knowledge about harmful algae throughout Chilean Humboldt Current system, particularly northern regions, such as Atacama Coquimbo. Therefore, number blooms occurred fjords channels, those minor economic impacts for artisanal fishermen mussel farming sector, might underestimated.