EXPERT REACTION: Should SA's toxic algal bloom be declared a natural disaster?

In my opinion, the magnitude of this algae bloom and devastation of fish and marine life could meet the definition of a national disaster. It could also qualify as a 'Matter of National Environmental Significance' under the Commonwealth Environmental legislation (EPBC Act). It is certainly an environmental contamination event that has been brewing for several months and has a growing harmful footprint. It urgently needs to be thoroughly researched to evaluate exactly what factors are contributing to the toxic nature of the algal bloom. Collecting detailed scientific data right now is essential. This will help provide insights into options for managing a complex and harmful situation. Controlling algal blooms is historically very difficult. The environmental conditions that promote their occurrence and severity can take years to develop. And many factors such as solar radiation and ocean temperature are beyond our immediate control. I am unsure that an ocean algae bloom of this nature can be controlled. I suspect it is more a case of understanding what the triggers are for alerting communities of future potential blooms. But right now, we need to consider what are the most urgent actions that need to be taken to limit further environmental and potential human health harm.

It doesn’t take a marine scientist to see that there is an ecological disaster unfolding in South Australia across 100kms of coastline. While most of us can’t see the fire burning, we can smell the smoke. It is a disaster of national significance, not just because of the environmental and economic impacts, but because the cause is not something we’re used to working with - not at this scale at least. While harmful algal blooms have been known to science for a long time, the severity, duration, and spread of this HAB is something I don’t think Australia has seen before and I think it is in Australia’s interest to understand everything we can about the bloom, as well as mitigation and recovery strategies, before it happens again, which could be very well somewhere else.

It’s hard to overstate the extreme severity of the algal-bloom environmental crisis in South Australia. We are talking about extensive mortality of nearly 500 different marine species, including key habitat-forming sponges and other invertebrates, as well as fish, over more than 500 km of coastline. It’s completely devastating.

This kind of extreme event, fuelled by a combination of high temperatures and pollution, is unfortunately not the first marine climate-driven catastrophe we witness in Australia’s Great Southern Reef. Extreme heatwaves caused extensive mortality of kelp forests along more than 150 km of coastline in Western Australia in 2011 and led to major aquaculture losses and new disease outbreaks in Tasmania in 2015-16.

We urgently need federal leadership to properly understand and respond to the South Australia toxic algal bloom crisis. This algal bloom is symptomatic of wider climate change impacts that are happening across all states, and need to be tackled in a coherent way. Unfortunately, these extreme events are only predicted to increase in both severity and frequency in the next decades, and we need to properly understand the full magnitude of all impacts so that we can accurately diagnose the problem and prepare management responses. There are potential interventions that can and should be considered, including reducing local stressors such as pollution and potentially rescuing endangered/ EPBC listed species in areas not yet impacted.

Calls for a declaration of a national disaster conflate two separate issues.

Is it a National Emergency?

The first issue is whether we should declare the algal bloom to be a national emergency.
This kind of declaration can be made if there is an emergency that is causing (or is likely to cause) harm that is ‘nationally significant’. Nationally significant harm means harm that has a significant national impact because of its scale or consequences.

Declaring a national emergency can streamline some national government activities, and may support a ‘major disaster determination’ which provides access to one-off and short-term Centrelink payments (more on this, below). A national emergency declaration is also important because of its symbolic effect. It acknowledges that something is really, really important. The floods in Lismore in NSW and in southern Queensland in 2022 were declared a national emergency under this same power. The SA Government may be able to make the case that this algal bloom – and the marine heatwave across southern Australia that preceded it – ought to be declared a national emergency. A declaration like this would bring the SA algal bloom, and the decimation of the SA marine environment and communities that rely on it, into the national spotlight.

Can the Australian Government provide relief funding?

The second issue is whether the Australian Government can provide financial support and other resources to help people who are affected by the algal bloom.
There are two kinds of national funding relevant here. One is the Disaster Recovery Funding Arrangements, administered by the National Emergency Management Authority (NEMA). These arrangements cover national funding that can be allocated to state/territory governments to help with disaster relief. Support can include ‘hardship payments’, loans and grants, community recovery funds, and other resources to support communities and businesses affected by a disaster. This first kind of funding is only available for ‘eligible natural disasters’. Eligible disasters are defined as ‘rapid onset’ events, including bushfires and floods. The disaster relief funding arrangements do not specifically provide for algal blooms or slow-onset disasters such as marine heatwaves (or land-based heatwaves, for that matter). This is a big problem because extreme events can be fast (like fires) or very slow (like droughts and heatwaves), but both kinds can cause serious harm. These funding arrangements will need to be more flexible as the climate changes.

The second kind of funding is administered by Centrelink. It includes disaster recovery payments or a short-term allowance that individuals have to apply for themselves. The relevant Minister can make a determination (which is like a decision, in writing) that a ‘major disaster’ exists if an extreme event has such a significant impact on individuals or an entire industry that a government response is required (including because it is unusual, or nationally significant). The Minister can also make a major disaster determination if there is a national emergency declaration in place (see first point). If the Minister makes a major disaster determination, people can apply to Centrelink for a one-off payment if they are negatively affected by the major disaster (i.e. seriously injured, their home is destroyed, or their major assets have been destroyed or suffered major damage directly because of the disaster). People may also be eligible for a short-term allowance (equivalent to the JobSeeker Payment for up to 13 weeks) if they live in or earn an income in an affected area and have experienced a loss of income directly because of the major disaster.

Blooms of this species of algae (Karenia mikimotoi) have been recorded throughout the world for the past 100 years but have been mostly reported since the 1960s. This species of algae has several adaptations that may have enhanced its ability to grow in the context of the South Australian blooms. It can ‘swim’ up and down in the water column which allows it to take up nutrients from the deeper layers of water when there is little mixing as has been the case in the waters off South Australia this year. The warmer conditions typically favour most algal growth and this species is no exception. It also has a wide temperature tolerance, which might help explain its persistence into winter. It also has an ability to assimilate the ‘remains’ of other algal blooms, which might link it to the Murray River floods in 2023 which released vast amounts of nutrients that stimulated algal growth then, and it is possible that these nutrients are still rippling through the food web. In addition, these blooms have been linked to materials derived from catchments such as natural organic matter further underscoring the possible link with the Murray floods.

This bloom highlights the extremely complex feedback between ocean temperature and mixing and possibly flood events and how this affects our environment and the industries that rely on this. While there have been no attribution studies between the event and climate change yet, the factors likely to be driving this bloom are being amplified by climate change. As a scientist, I don't think it is my role to advise if this is a national disaster (which is a political decision), but I would advise Mr. Watt to consider events such as this when making decisions on projects in relation to greenhouse gas emissions. I would also suggest the government strengthen national capability in monitoring and linking the complex factors that control ecological response to climate change to provide warnings of their occurrence and risk to Australia's environment and associated industries.

The recent algal bloom in South Australia has wreaked havoc on the region's marine ecosystem, with far-reaching consequences for the fishing and aquaculture industry, and coastal communities they support. This could very well be considered a national disaster.

The event has already resulted in closures to the Coorong’s pipi fishery and parts of the State’s oyster aquaculture sector due to the risks posed by harmful toxins and is also causing widespread deaths among important recreational and commercial fish species.

The impact of the algal bloom appears to have been particularly severe on less mobile species such as leatherjackets, seahorses, flathead, puffer fish and some rays. Many of these species are long-lived, meaning that recovery of populations may take years.

This ecological catastrophe has not only affected individual species but has also had a profound impact on marine habitats and the food webs they support. These major changes have the potential to have significant long-term consequences for the marine environment.

The fishing industry and coastal communities, already working through the implications of fishery closures brought about by fishing practices, now face additional challenges in the wake of this disaster.

Whilst it is difficult to attribute single events directly to climate change, the combination of extreme sea surface temperatures, intense rainfall, and the particularly weak westerly winds that led to this algal bloom aligns with long-standing predictions of more frequent extreme weather events. These interconnected factors suggest that similar occurrences may become more common in the future, highlighting the need for increased vigilance and adaptive management strategies in coastal and marine environments.

To address this crisis, it is crucial to better understand the impact on fisheries and implement measures to support both the industry and affected communities. Additionally, efforts must be made to facilitate the rebuilding of marine life and the fisheries they sustain, ensuring the long-term resilience of South Australia's coastal ecosystems.

The scale and duration of this event is unprecedented.

There has been serious loss of marine life, widespread damage to the environment and significant economic and social disruption.

Apart from considerations about hardship payments for businesses, there is a need for Australia to become better prepared for these natural disasters, to develop surveillance and early detection systems, set up emergency response measures to mitigate against the spread and accelerating losses, and to undertake fundamental research to understand and more readily manage such events in the future.

We cannot just treat this as a one-off event that should be monitored. This is a complex problem and we need a coordinated science-industry-governance response to be more strategically positioned for such events in the future.

The harmful algae bloom has blanketed large areas of South Australia’s coastline and has already killed many fish, sharks, and a wide diversity of other marine life, with devastating environmental and economic effects.

The fragmented bloom has drifted north into Spencer Gulf, into the internationally significant Coorong wetlands, and even the Port River, where limited flushing means the impacts could linger for months in these fragile and internationally important ecosystems. Should prevailing currents carry it to WA or VIC, neighbouring coasts may face the same ecological and economic shocks within weeks.
Whether we label this a ‘national disaster’ is a legal decision, but scientifically, the scale, potential cross-jurisdictional reach and multi-year legacy effects are on par with the bushfires and floods that routinely trigger federal interventions.

A national declaration might unlock coordinated monitoring, emergency support for fisheries and wildlife rescue, and the rapid mobilisation of Australia’s research capability to forecast bloom trajectories and investigate potential mitigation tools such as nutrient-load reduction – particularly where the bloom enters restricted coastal wetlands which are not easily flushed by oceanic currents.

Long-term prevention requires tackling the drivers: record temperatures and high nutrients. Without concerted action, events like this risk becoming the new normal.

I have been researching marine harmful algal blooms (HABs) in Australia for the past 25 years, including advising government and industry on HABs.
 
Yes, this particular HAB of Karenia species, principally including Karenia mikimotoi, is a national disaster in my opinion. Its impacts are far larger and more broad-ranging than any other HAB that we have experienced in Australia.
 
It has devastated an area of several hundred square kilometres of coastline since mid-March, and is now impacting Adelaide, a city of 1.5 million.

Brevetoxins have been found in some seafood from this HAB, which are neurotoxins with potentially severe impacts if contaminated seafood is consumed. Commercial seafood harvesting in impacted regions has been suspended, hence there is no risk due to the consumption of commercial seafood. Recreational fishers should be advised not to fish in the area.
 
It is not just having an ecologically disastrous effect, it is now severely impacting fishing and aquaculture industries as well as tourism. We need regular monitoring and financial support for all affected.

South Australia’s harmful algal bloom is a major ecological crisis that is crying out for help from the government. While not yet formally declared a national disaster, the scale of this event, spanning hundreds of kilometres of coastline and devastating huge numbers of marine life, is unprecedented for the region and demands national attention. Algal blooms are caused by rapid growth of microscopic algae, triggered by a mix of warming ocean temperatures (climate change), nutrient pollution, and limited ocean movements. In this case, unusually warm waters and calm conditions appear to have created the perfect storm. This is climate change in real time. The consequences of years of inaction are now unfolding before our eyes.

The impacts are severe: mass fish kills, oxygen depletion in coastal waters, and huge risks to aquaculture, fishing, tourism, and even human health.

There’s no quick fix, but solutions include reducing nutrient runoff, better coastal monitoring (more funding!!), and acting on climate change — the key driver making these events more frequent and intense. If this was happening in more populous areas, action would have already been taken to call this a national disaster. Without serious changes, we can expect more of these ecological shocks in the future.

The scale and impact of the SA algal bloom is unprecedented in recent times. It initially occurred concurrently with a major drought in South Australia. The scale of the bloom presents enormous challenges for managing and controlling it. At a time when there is enormous pressure to provide a ‘quick fix’, it is critical that whatever action is undertaken can be shown to be scalable and feasible before implementation. These types of challenges can be expected to increase in the future with the combination of human pressures on ecosystems and climate change increasing mean and extreme temperatures beyond historical norms.

The current algal bloom affecting South Australia is not just an environmental event: it is an ecological disaster on par with bushfires and floods, and it should be formally recognised as such. These blooms can devastate marine ecosystems, causing mass die-offs of mammals, fish and invertebrates, threatening biodiversity, and undermining the livelihoods of fishers and coastal communities. As with other natural disasters, people who depend on the sea for food, work, and cultural identity need timely support and access to disaster relief. Climate change, warming waters, and nutrient runoff are driving the increasing severity and frequency of these events. Like a bushfire or floodwater, a toxic bloom can sweep through an ecosystem, and we must treat it with the same urgency.