Challenges And Opportunities For Commonwealth Fisheries

Predicted climate change impacts on the Australian marine environment include increases to sea surface temperature (especially in the waters off south-eastern Australia); rises in sea level; altered ocean current, wind and rain patterns; increases in ocean acidification; and increases in the frequency and intensity of tropical cyclones and storm events.

Fisheries generally operate within an environment of uncertainty. Variability in fish prices, fish abundance and availability, and weather all contribute to this uncertainty. Climate change presents Australian fisheries with a new source of uncertainty, which will have implications for commercial fishing (including aquaculture), and for recreational and Indigenous fishers.

This report aims to assist policy by identifying:

• the components of Commonwealth fisheries most vulnerable to climate change
• research gaps
• possible ways to improve resilience and capitalise on opportunities.

This is done through case studies of the Eastern Tuna and Billfish Fishery, Northern Prawn Fishery and Southern and Eastern Scalefish and Shark Fishery—Commonwealth Trawl Sector.

Determining the likely impacts of climate change on the aquatic environment is complicated. Not only are there uncertainties in the model projections, but there are also large gaps in our understanding of marine ecosystem processes. Variability in ocean currents, winds, nutrient levels and fish populations and uncertainty over future greenhouse gas emission levels complicate the assessment of climate impacts, particularly when time frames and other stresses are taken into account. Not surprisingly, the likely effects of climate change on Australia’s commercial and recreational fisheries and aquaculture are not immediately clear.

Some of the potential effects of climate change on target species in Commonwealth fisheries include changes to carrying capacity and productivity, distribution and abundance, recruitment including larval dispersal and settlement, growth rates and availability of prey.

Climate change will bring many challenges and opportunities for fishers. Depending on the fishery, climate change may cause changes (either positive or negative) to access and fishing costs, catch quality, storm activity, abundance and catch levels and distribution. Fishers switching target species may have difficulties in fisheries with quotas, unless trading and asset value are properly managed. Commonwealth fisheries need to be very adaptable. In the short term, fishers face considerable interannual variability in the availability, abundance and location of target species, as well as economic factors such as the changing Australian dollar, fuel prices and access to markets. They are able to adapt by changing fishing practices such as switching target species, fishing location, or modifying gear.

There is a need to evaluate whether managers and researchers will be able to detect any changes due to climate change in the fisheries data already collected, and (if so) on what time scale. Regardless of whether changes to biomass, catch or distribution are solely due to climate change, the early detection of changes maximises the time available in which to respond appropriately. The ability of fishers to switch target species in the short term depends on the availability of suitable quota, the amount of flexibility to trade it, and the suitability of the current gear. There may also be issues surrounding the asset value of quota. It is also dependent on the suitability of the current gear.

While the possible changes due to climate change are an important issue for Australia’s fisheries, in the short term other issues such as markets, cost of inputs and overexploitation are likely to have a greater effect and be higher priority for individual operators. Climate change may affect management tools such as temporal and spatial closures, which are typically based on historical fishing patterns and current distributions. There may also be jurisdictional issues, particularly for straddling stocks, which may change distributions.

The Commonwealth Fisheries Harvest Strategy Policy (2007) accounts for climate-induced changes (as well as other environmental impacts) through the use of the ‘exceptional circumstances’ category. These circumstances, invoked under established criteria, would override management advice arising from the straightforward application of the harvest strategy, if (for example) there has been a change in the ecological environment of the fishery unrelated to impacts of fishing. However, it is important to know how climate change may affect the total carrying capacity of each fishery and therefore, estimates of maximum sustainable yield and maximum economic yield. If projected changes due to climate change occur gradually (and do not result in sudden regime shifts), and management arrangements and policies retain some flexibility, many Commonwealth fishers should be able to adapt.

Full story: TheFishSite