Harmful Algal Blooms in Australian Coastal Waters: Surprises from Climate Change?

Professor Gustaaf Hallegraeff1

1Institute for Marine and Antarctic Studies, Hobart


Microscopic plankton algae provide critical services to human society by generating through photosynthesis every second breath of oxygen we inhale. They also form the basis of all food chains leading to edible fish. Sometimes -so-called- harmful algal blooms can cause severe economic losses by discoloring the water and damaging tourism, killing fish through oxygen depletion, damaging or clogging of gills, but more seriously by contaminating seafood with potent neurotoxins. Algal blooms may also pose unexpected problems for desalination plants.

While microalgal blooms in a strict sense are completely natural phenomena, since the 1980s their impacts on Australian public health, tourism, and fisheries have increased in frequency, intensity and geographic distribution. To a major extent this reflects increased scientific awareness. In other cases, algal bloom problems reflect increased utilisation of coastal waters for aquaculture and fisheries. Eutrophication has rarely been rarely invoked as a causative factor. Other harmful species have been newly introduced via ship ballast water discharge or have exhibited significant range expansions in relationship to climate change.

Environmental agencies and aquaculture industries worldwide are increasingly forced to invest in improved technologies for monitoring for an increasing number of harmful algal species in water samples and increasing complexity of algal toxins in seafood products. Climate change is calling for increased vigilance in seafood safety.


Gustaaf Hallegraeff is a Professor at the Institute of Marine and Antarctic Studies of the University of Tasmania in Australia. He has supervised 40 PhD students and worked on a wide range of Harmful Algal Bloom issues from shellfish toxins, climate change, ship’s ballast water to fish-killing algae. He is a Fellow of the Australian Academy of Technological Sciences and Engineering, and winner of the 2004 Eureka Prize for Environmental Research and 2014 Lifetime Achievement Award by the International Society for the Study of Harmful Algae.