The main climate pressures affecting the marine environment in Western Australia are changes in ocean temperatures, the seasonality and location of storms and increasing ocean acidity. Understanding the effects of changes on fisheries and the marine environment can assist in understanding the likely impacts to coastal communities.
The settlement of rock lobster puerulus (larvae) close to shore is thought to be negatively impacted by altered seasonality and location of storms. In particular, alterations to the pattern of westerly winds affects puerulus settlement. This has had substantial impacts on the rock lobster fishing industry and has resulted in a reduction in quota, amongst other management changes. Rack- and pen-based aquaculture, diving and charter fishing (marine tourism activities) are all negatively impacted by storms. Storms can damage assets such as stock and infrastructure in aquaculture businesses (pearl oyster, finfish), and reduce the number of days marine tourism ventures can operate.
Commercial fishing and ships, ports and marinas are negatively impacted by warming ocean temperatures. This is because extreme heatwaves such as that observed in 2010 cause fish kills and allow pests and diseases to reside in ports and other areas frequented by non-local vessels. Additional regulations may be placed on shipping, and monitoring/remediation may be required to deal with pests and diseases in ports and marinas. In contrast, increased ocean temperatures may have a positive impact on recreational and charter fishing by bringing popular warm water species further south closer to population centres.
Increased ocean acidity can negatively impact the marine tourism industry through dive charters that focus on coral reef diving. Increased ocean acidity is detrimental to coral growth and may reduce the quality of Western Australia’s coral reefs.
High value species
Western Australia’s commercial wild capture fisheries had a total value around $285m in 2010/11, while the catch was 22 707 t. Consistent with the general decline in fisheries value and production in Australia, commercial wild capture fisheries in WA experienced a 30% drop in catches and 28% drop in gross value between 2006 and 2010 (ABARES 2011). This decline is likely to be due to multiple factors including changes to international (export) markets, the value of the Australian dollar and operational costs.
The highest value fishery species in WA in 2010/11 was the western rock lobster (approximately $184m), substantially more valuable than the second most valuable species, red throat emperor (approximately $35m). Other highly valued fisheries include abalone and prawns (both multiple species).
Rock lobster production was also the highest in WA at approximately 5200 t in 2010/11. Prawns and scallops had the next highest production at 3233 t and 3058 t respectively. In contrast to its high value, abalone production was only 300 t.
Western Australia’s aquaculture sector was dominated by pearl oysters (approximately $99m) and multiple species of finfish (approximately $89m) in 2010/11. The value of pearl oysters is determined largely by export markets as 98% of WA’s farmed pearls are sold internationally. Other aquaculture species include mussels, marron and yabbies.
A study into recreational and Indigenous fishing found that approximately 28% of Western Australians participated in recreational fishing between May 1999 and May 2000 (Henry and Lyle 2003). This was the third highest rate of participation behind the Northern Territory and Tasmania. These fishers catch mainly dhufish, blue swimmer crabs, herring and mackerels.
In addition to fishing and aquaculture, Western Australia has the largest and most valuable shipping/sea freight industry in Australia. WA also supports a marine tourism industry and employs a relatively high proportion of people in its ports.
The active shipping/sea freight industry in WA is used by the mining industry as well as agricultural and other exports. In 2010/11 the value of the imports and exports shipped through WA ports was almost 30% of the Australian total. In addition, the tonnes moved through WA ports was approximately 50% of the total shipped through Australian ports (includes exports and imports). The number of people employed in WA ports was approximately 470 which accounted for almost 18% of total port employees in Australia.
Marine tourism is relatively important in WA with whale- (and whale shark-) watching operators, participants and value ranked third of all Australian states. The growth of this industry is small, however, lagging behind all states except Victoria. Scuba diving is a popular recreational pursuit particularly near Perth and Ningaloo Reef (Exmouth). Western Australia has approximately 10% of Australia’s yacht clubs and is ranked fifth, ahead of Tasmania and New South Wales.
Climate and sealife
See Climate and sealife – species sensitivities page for detailed information