Fisheries
In 2006-07, the gross value of Australian fisheries and aquaculture production was $2.18 billion, with a total export value of $1.49 billion. Approximately 35 per cent of Australia’s gross value production, or $793 million, was from aquaculture production.
The commercial fishing industry employed approximately 9700 people in 2006, with a further 6200 employed in associated wholesaling and processing industries.
The most valuable species in 2006-07 were rock lobster ($441 million), salmonids ($281 million), prawns ($265 million), abalone ($216 million) and tuna ($161 million).
Climate change impacts
The impacts of climate change on marine ecosystems and fish stocks are expected to be driven by changes in temperature, rainfall, ocean chemistry, ocean currents, nutrients and extreme weather events. These impacts are likely to vary by region. For instance, increases in sea surface temperature are potentially a key impact on south-east fisheries, while northern fisheries are most likely to be affected by changes in rainfall.
Increased water temperatures
It is projected that the greatest increase in sea surface temperature will occur off south-east Australia. Summer sea surface temperature records already indicate an increase of more than 1°C since the 1940s off the east coast of Tasmania.
Increases in sea surface temperature are likely to affect the distribution of many species in the south-east and offshore, with potential flow on effects to the broader marine ecosystem.
The projected increase in sea surface temperature may also have adverse impacts on the production of cool-water farmed aquaculture species, such as the salmon production industry in Tasmania.
Changing rainfall patterns
Coastal aquaculture may be impacted by altered rainfall patterns due to changes in salinity levels, and suspended sediment and nutrient loads.
The projected decline in rainfall may affect freshwater aquaculture industries as a result of reduced water availability.
Changes in rainfall may negatively affect barramundi, prawn and mud crab production in northern fisheries.
Ocean chemistry
Changes in ocean chemistry may affect plankton communities that underpin marine food webs, with possible flow-on effects to other species such as commercial fish. Ocean acidification may also affect the eggs and larvae of commercial species, and affect some aquaculture species, such as mussels and oysters. The vulnerability of coral reefs to changes in ocean chemistry may also have implications for reef-dependent fisheries.
Extreme weather events and rising sea levels
Climate change is expected to result in more intense storms, which may impact offshore and coastal aquaculture stock and infrastructure.
Coastal habitats, which provide important breeding and nursery grounds, may be affected by sea level rise due to climate change. For instance, the extent of mangrove areas, which provide critical habitat for prawns and estuarine fish, may be reduced in the Gulf of Carpentaria as a result of sea level rise.
This information has been sourced from a range of materials, including: Antarctic Climate & Ecosystems CRC (2008) Position Analysis: CO2 and climate change: ocean impacts and adaptation issues. Australian Bureau of Agricultural Resource Economics (2008), Australian Fisheries Statistics 2007; Hobday, A., Poloczanska, E., Matear, R. (2008) Implications of Climate Change for Australian Fisheries and Aquaculture: a preliminary assessment