Algal blooms, like this one in the Tasman Sea seen from satellite in 2004, have implications for the ocean food chain.

Fisheries in a future ocean: impacts of climate change

The impacts of our changing climate on the oceans will have an impact on Australia’s fisheries.

• 19 August 2008 | Updated 14 October 2011

• Impact on fisheries 
• Other pressures on fisheries

Climate Adaptation Flagship scientists have modelled changes in climate and ocean conditions for a range of carbon dioxide emission scenarios.

The modelling has highlighted changes in a range of variables that will influence Australian fisheries and aquaculture, including:

• temperature
• ocean currents
• winds
• nutrient supply
• rainfall
• ocean chemistry
• extreme weather conditions.

Changes over decades or more in ocean temperatures and nutrient availability will affect the range and productivity of fishing grounds and all tiers of marine biodiversity, with economic and social consequences for fishing industries.

For example, models predict a southward contraction in the range of southern bluefin tuna off Australia’s east coast, and an expansion in the distribution and abundance of yellowfin tuna.

Impact on fisheries

By 2030 we can expect to see a range of likely impacts of changing climate and ocean conditions, including:

• a regional shift in wild fish stocks
• changes in spawning times
• a contraction of suitable habitat for salmon farming reliant on cool water conditions
• habitat change because of species invasions
• higher intensity extreme weather events affecting onshore and coastal aquaculture.

Other projected climate change impacts include:

• benthic and demersal fish species will keep shifting south, most prominently in the eastern and south-eastern region
• some populations may decline where ranges are bounded by open water to the south
• continued decreases in the zonal west winds are likely to lead to continued depletions and potential collapses of demersal fish stocks
• changes in temperatures, current patterns, and primary and secondary production may affect larval fish health and transport thereby influencing recruitment potential
• climate change impacts will potentially combine with fishery impacts to exacerbate further depletion of groundfish stocks.

Other pressures on fisheries

The fishing pressure on Australia’s commercially important benthic and demersal fish stocks is substantial in many regions.

Eight of the 17 stocks listed as overfished, in the Australian Bureau of Resource Sciences 2004 annual report on the state of Australia’s fisheries, are in the southeast demersal fishery group.

The effect of fishing is presumably so important that assessments and projections of climate change impacts should not be conducted without considering the impacts of fishing in the area of interest.

Pollution should also be considered a stress that reduces the resilience of benthic and demersal fish assemblages to climate changes.

Find out more about CSIRO’s work in Aquaculture.