The main climate pressures affecting the marine environment in Tasmania are changes in ocean temperatures, rainfall and ocean acidity. Understanding the effects of these changes on fisheries and the marine environment can assist in understanding the likely impacts to coastal communities.
Increased ocean temperatures are likely to have a positive impact on recreational and charter fishing. This is because popular fish species that usually live in warmer waters are now able to live in Tasmanian waters. Negative impacts from increased ocean temperatures may occur for commercial fisheries and ships, ports and marinas. Negative impacts may occur because warmer waters allow pests and diseases, such as the long-spined sea urchin (Centrostephanus rodgersii), to flourish in Tasmanian waters when the cool waters had previously excluded them.
Rack- and pen-based aquaculture are negatively affected by changes in rainfall, particularly flood events. Floods wash bacteria, nutrients and pesticides into coastal waters which can result in the forced stoppage of oyster harvesting and may affect aquaculture production. Rack-based aquaculture in Tasmania may also be negatively impacted by increased ocean acidity which is thought to soften the shells of molluscs including oysters.
High value species
Tasmania supports a high value fishing industry with wild capture fisheries having a total value over $160m in 2010/11 (4 662 t). In contrast to a general decline in commercial wild capture fisheries production in Australia, Tasmania’s commercial fisheries increased in both tonnage (33%) and gross value (36%) between 2006 and 2010 (ABARES 2011). This increase may be due to numerous factors including changes in export markets and fisheries management regulations.
The highest value species was abalone (approximately $97m) followed by southern rock lobster (approximately $60m). Other high value commercial species include giant crab (approximately $2m), banded morwong (approximately $1m) and octopus (approximately $420 000). Similar to value, fishery production in 2010/11 (t) was highest for the abalone fishery (2700 t) followed by the rock lobster fishery (1275 t). The total production from Tasmania’s commercial fisheries was 4561 t split between 19 species and groups of species.
In 2010/11, Tasmania’s aquaculture sector was the largest (38 882 t) and most valuable (approximately $432m) in Australia. Salmonids (e.g., Atlantic salmon) had the highest production (34 229 t) and value (approximately $400m) of aquaculture species in Tasmania followed by oysters (3913 t, $23m).
Henry and Lyle (2003) found that recreational and indigenous fishing participation in Tasmania was relatively high at nearly 30%. This was second behind the Northern Territory. These fishers catch mainly flathead, trout and Australian salmon.
In addition to fishing and aquaculture, Tasmania has an active shipping/sea freight industry as well as marine tourism and employment in ports and yacht clubs.
Tasmania has a relatively small active shipping/sea freight industry moving approximately 6 million tonnes worth $2181m per year. Tasmanian ports employ approximately 287 people on both a full-time and part-time basis. Tasmanian ports employ 10% of the total number of people employed in ports in Australia.
Tasmania has a small marine tourism industry which includes whale-watching and scuba diving businesses. The whale-watching industry has only two operators and approximately 24 000 participants. However, in comparison to other states, Tasmania’s industry has the highest average annual growth (37%) in Australia. Participation in scuba diving is very seasonal and focused largely on the east coast of Tasmania.
Approximately 7% of Australia’s yacht clubs are in Tasmania and recreational boat ownership is very high (Henry and Lyle 2003), particularly in Hobart.
Climate and sealife
See Climate and sealife – species sensitivities for detailed information