98% of Queensland prawn areas at risk of inundation by rising seas this century
- Written by The Conversation
As climate change wreaks havoc with the world’s oceans, future production of fish, crustaceans and other aquatic organisms is under threat.
Our new research shows how this disturbance will play out for Australia’s prawn industry, which is concentrated in Queensland. We found by 2100, sea level rise threatens to flood 98% of the state’s approved prawn areas.
The problem is not confined to prawns – Queensland barramundi farming is also at risk from sea-level rise. Climate change also poses challenges for other major seafood industries in Australia, including salmon in Tasmania.
Australian seafood is vital to our culture and diets, and the national economy. We must take steps now to ensure the aquaculture industry thrives in a warmer world.
Spotlight on Queensland prawns
Aquaculture refers to breeding, rearing and harvesting fish, crustaceans, algae and other organisms in water. Australia’s aquaculture industry is expected to be worth A$2.2 billion by 2028–29.
Aquaculture can involve a variety of methods, from ponds and sea cages to indoor tank systems and even giant ships.
Aquaculture is one of Queensland’s fastest-growing primary industries – partly due to burgeoning production in prawn farming.
Queensland is also expected to experience a 0.8m sea-level rise by 2100, under a high-emissions scenario. Our research investigated how this could affect the state’s aquaculture industry.
We did this by examining existing data on coastal inundation and erosion from sea-level rise, combined with data on current and future aquaculture production areas.
We found 43% of sites where aquaculture production is currently occurring are at risk from sea-level rise. Prawn farming is the most vulnerable.
About 98% of areas approved for prawn farming in Queensland are expected to be inundated by seawater by 2100. The risk includes 88% of areas currently producing prawns. Prawns are grown in large ponds on land near the coast with access to saltwater, which makes them particularly vulnerable to inundation. Annual prawn production losses due to sea-level rise could reach up to A$127.6 million by century’s end.
Inundation and coastal erosion can cause breaches in pond walls compromising their structural integrity. These risks may be amplified when sea-level rise coincides with coastal flooding. Rising seas can also increase salinity in surrounding soils and groundwater, further affecting ponds. Other aquaculture infrastructure, such as hatcheries, buildings, and roads, may also be disrupted.
The Gold Coast region – a prawn production hub – is particularly vulnerable. Damage caused by ex-Tropical Cyclone Alfred highlights the vulnerability of coastal infrastructure to extreme weather. This will only worsen as the planet warms.
Queensland barramundi farms also face a serious threat. Some 44% of areas producing barramundi are likely to be exposed to inundation, causing up to A$22.6 million in annual production losses. Meanwhile, two of Queensland’s designated “Aquaculture Development Areas” – regions earmarked by the state government for industry expansion – may be unsuitable due to future sea levels. Both are located in the Hinchinbrook Shire Council area.
Beyond rising seas
Globally and in Australia, climate change is posing myriad challenges to seafood farmers.
Rising water temperatures stress animals such as salmon, lowering oxygen levels which slows growth rates and increases their risk of disease. Such depletion is a particular concern in already low-oxygen environments, such as Tasmania’s Macquarie Harbour.
Ocean heatwaves can cause mass fish deaths and devastate production. In Tasmania in February, more than 5,500 tonnes of dead fish were dumped at southern Tasmanian waste facilities – a problem linked to warmer water temperatures.
Dead and decomposing fish can further alter oxygen levels in water, spread disease to wild populations and attract scavengers. In the Tasmanian case, fish remains washed up on public beaches, angering the public and leading to calls for greater industry regulation.
Extreme weather further complicates aquaculture operations. Storms, flooding and abnormal rain patterns can affect water salinity which impacts species growth and survival. They can also damage vital infrastructure, which may allow animals to escape.
This occurred in 2022, when repeated flooding and disease outbreaks on oyster farms in New South Wales led to complete stock losses, prolonged farm closures and workers being laid off.
Surviving a warmer future
Not all aquaculture operations will suffer under climate change. Warming waters can lead to longer growing seasons in temperate regions. It can also expand suitable habitat for tropical species such as tilapia, mussels and oysters. Regions previously inhospitable to aquaculture may become viable production zones.
For the countries and producers that are expected to suffer, those that plan for and adapt to climate shifts can minimise losses.
Key steps industry and government can take include:
planning farms in lower-risk areas and relocating vulnerable sites
implementing climate-resilient infrastructure and restoring coastal ecosystems near farms to buffer against climate impacts
expanding to include diverse species and selectively breeding stock that can tolerate the changing conditions
strategic government policies and planning, financial incentives, and investment in resilient infrastructure to help the industry stay ahead of climate risks.
With the right strategies, Australia’s aquaculture industry can adapt to a changing climate and continue to contribute to food security and community wellbeing.
