Summary
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.
Discussion
While climate change is an important issue for Commonwealth fisheries, in the short term other issues such as markets, input costs and overexploitation are likely to have a greater effect and be higher priority in the short term for individual operators (Cochrane et al. 2009). Domestically, the Australian Fisheries Management Authority (AFMA) is keeping a ‘watching brief’ on climate change. It has concluded that climate change will not require specific management actions in the short term (AFMA 2009). However, AFMA has identified the importance of monitoring climate change related research. In the longer term, fisheries management and policy-makers will need to ensure that any management and policy measures consider future changes in fish abundance and distribution, and fisher behaviour that may follow from climate change related factors. Policies and management measures will need the flexibility to allow fishers to adapt to changes while still ensuring that stocks are harvested in a sustainable manner.
Commonwealth fisheries are a very adaptable industry. In the short term, fishers face considerable interannual variability in the availability, abundance and location of target species, as well as changes in economic factors such as the value of the Australian dollar, fuel prices and access to markets. Fishers in Commonwealth fisheries can adapt by changing fishing practices such as switching target species, fishing location, or modifying gear. In the long term, fishers have adapted to changes in policy and management, such as the introduction of quotas and effort restrictions, and decreased access through spatial closures and reduced TACs. If anticipated changes from 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.
The case studies featured in this report were chosen because they represent the diversity of Commonwealth fisheries. The report’s findings are transferable to other comparable fisheries. Challenges and opportunities faced by fishers in the SESSF–CTS, for example, are likely to be similar to those in other demersal scalefish fisheries such as the SESSF–Great Australian Bight Fishery. It is important to consider regional variations when comparing the findings. For example, when extending the findings from the ETBF to the Western Tuna and Billfish Fishery (another pelagic longline tuna fishery), there are also likely to be changes to the distribution of tuna species within this fishery as their presence is linked with oceanographic conditions. However, climate change is predicted to have different effects on the East Australian Current to those in the Leeuwin current in the west, and therefore the scale of any change in distribution is uncertain.
In recent years, there has been increasing focus on improving profitability in the fishing industry, as demonstrated by the Ministerial Direction and the Securing our Fishing Future structural adjustment package, and the resulting harvest strategy policy. Economics is an important driver of fishing effort in many Commonwealth fisheries. Fuel is a major cost for fishing vessels and often has a major impact on fishing activity. Changes to the distribution of fish that result in vessels having to travel further to fish, could make fishing financially unviable from some ports.
Instead of initiating climate change specific research, researchers may be able to use available data—such as catch, effort and observer data, environmental data, vessel monitoring system (VMS) and fisheries independent surveys—to determine whether fisheries are being affected by climate change. However, there first needs to be an evaluation of whether the current fisheries data collected will be able to detect a change. It is also difficult to know whether observed changes are due to interannual variability or long-term climate change, and whether changes in biomass are due to climate change or changes in fishing patterns.
With the spatial distribution of species potentially changing with climate change scenarios, current spatial and temporal management arrangements (e.g. marine protected areas, fishing seasons and closures) may no longer be suitable. These are typically based on historical fishing activities and do not necessarily account for future access issues. Changes in species distribution in response to climate change may affect current offshore constitutional settlement arrangements. They may also affect access to Commonwealth stocks by recreational fishers and increase interactions between recreational and commercial fishers. As a result, the suitability of these management measures may need to be reassessed.
At an international scale, changes to the distribution of fish stocks may increase access for some nations as stocks move into their EEZs, while moving out of other EEZs and decreasing availability to those nations. This may have serious implications for some small island nations in the Pacific Ocean who depend heavily on these stocks for food security and their economies. The contribution of fishing to the gross domestic products of these nations can also be substantial.
There are unlikely to be changes to domestic management arrangements from climate change in the short term (AFMA 2009). However, it will be important that management arrangements remain flexible to allow fishers to adapt while also managing stocks so that they do not become overexploited. Currently, fishers change fishing practices and location depending on the availability of their target stocks, market forces and fishery regulations.
The Commonwealth Fisheries Harvest Strategy Policy accounts for climate-induced changes (as well as other environmental impacts) through the use of exceptional circumstances. However, it is important to know how climate change may affect the total carrying capacity of each stock and therefore, estimates of maximum sustainable yield and maximum economic yield. The flow-on effect is the impact on calculating recommended biological catches and TACs.
In terms of ecosystem-based management, it is important to incorporate bycatch and threatened, endangered and protected species in analyses. Climate change is also likely to affect the distributions of threatened, endangered and protected species. Changes in these distributions could result in additional spatial and/or temporal closures in some fisheries. The nature of ecosystem based-management means that changes due to climate change may be discovered sooner than would occur under single species management.
In conclusion, while climate change is an important issue for Commonwealth fisheries, other issues such as markets, input costs and overexploitation are likely to have a greater effect and be a higher priority in the short term. Climate change may affect management tools such as temporal and spatial closures, which are typically based on historical fishing patterns. There might also be jurisdictional issues, particularly for straddling stocks, which could change distributions. It is important that management arrangements and policies retain some flexibility to allow Commonwealth fishers to adapt to changes of stock distribution and availability.
