Algal range expansions are possible as the climate warms into the future. With ocean warming, tropical species have the potential to extend their range into NSW coastal waters. In particular the dinoflagellate Pyrodinium bahamense, a producer of PSP toxins and responsible for >2,000 human illnesses and 100 deaths resulting from the consumption of contaminated shellfish and fish (Hallegraeff and Maclean 1989), is presently confined to tropical, mangrove-fringed coastal waters of the Atlantic and Indo-West Pacific (Hallegraeff 2010). However, the fossil cyst record shows that this species once existed as far south as 32°S, just north of Sydney, and has the potential to extend its range into more southern latitudes in future years.
Similarly, other tropical species belonging to the genus Gambierdiscus which produce ciguatoxins (CTXs) and possibly maitotoxins (MTXs) and are the causative species for ciguatera fish poisoning (CFP) in humans, may extend into more southern waters with the ‘tropicalisation’ of eastern Australia.
Another group of phytoplankton, the haptophytes, have potentially ichthyotoxic (toxic to fish) representatives which, although present in Australian waters, have never bloomed in eastern Australia to date. These include Chrysochromulina leadbeateri, Phaeocystis globosa, Prymnesium parvum and Prymnesium polylepis.