As a massive and extremely sparsely populated state, Western Australia has not suffered from the extent of environmental damage or overfishing that has been experienced elsewhere in the world. The key fisheries are well managed, and their value is recognized as a mainstay of the economy and an important aspect of tourism and recreation. Concerns primarily focus on the potential damage of bottom trawling, overfishing and aquaculture.
Marron and barramundi are both farmed. Marron are farmed in freshwater ponds and tanks, largely on a small scale basis. Careful management of water and discharge is an important requirement for any aquaculture operation, to limit impacts on local groundwater, and the invaluable waterways of a dry continent. Barramundi are farmed in open water cages and ponds. Government authorities review proposed farms carefully for the prospect of damage caused by new loads of nutrients, waste, and chemicals. Sites are chosen for their ability to rapidly disperse or process nutrients, and planning requirements ensure that farms are not placed too closely together. Barramundi are carnivorous species, and it takes up to two and a half pounds of fish meal to produce a pound of farmed barramundi. Aquaculture advocates argue that the wild fish harvested for fish meal and fish oil are not high-value species to humans, and that before fish farming became popular, the same quantity of fish meal was used to feed pigs and other livestock. However, the entire food chain is part of the equation, and the production of carnivorous farmed fish by harvesting wild fish is currently way too inefficient and damaging to important components of the ecosystem. Little conclusive evidence of environmental damage caused by barramundi aquaculture has surfaced to date.
Sea grasses are the critical primary producers for much of the WA marine environment, and bottom trawling for prawns and scallops have in the past inflicted serious damage to important seagrass meadows. New regulations, active monitoring of target environments, and improvements to trawling techniques have demonstrated significant improvements to habitats where trawling is practiced, and most importantly, general awareness of the value of the seagrass beds has risen dramatically.
The most important commercial fisheries have been managed well, and the rock lobster fishery is a good example. It was one of the first fisheries in the world to be certified as sustainable by the Marine Stewardship Council. To the north of the state, illegal foreign fishing is a major concern due to its intense focus on trocus shell and shark fin, high value products in Asian markets. Solutions to the problem are not easy as the driving factors are diminishing fish stocks and growing poverty levels in fishing communities throughout the region to the north.
Recreational fishing in WA also presents a major environmental risk, despite the relatively small population base. Overfishing of pink snapper attributed to the recreational sector led to the near collapse of that species in Shark Bay in the 1990s. Most Western Australians live on the coast, and populations are concentrated in Perth and the southwest. With 34% of the population going fishing, this amounts to real pressure on highly prized species. WA has strict regulations on the taking of shellfish and fin fish, which include minimum and maximum size limits, seasons, and restrictions on taking breeding stock. Maximum size limits are important for preserving barramundi stocks, as all barramundi are born male but the older and larger fish become females, the prime breeding stock. The fishing community is increasingly becoming conscious of the importance of sustaining breeding levels of fish, and of the need to safely handle fish that are caught accidentally and returned. This is especially important for fish such as dhufish which are endemic to WA and only occur in the most populated section of the coastline. Dhufish are particularly prone to barotrauma, the effects of rapid ascent from depth, which caused internal gasses to expand as pressure decreases. The effects are brought on by anglers pulling fish up from a depth of 80 feet or greater, and can cause the stomach of fish to be pushed right out of its mouth. In the past, undersized dhufish that should be returned safely rarely survived the impacts of barotrauma, but new devices called ‘release weights’ increase survival rates significantly. Release weights are attached to the jaw of a fish and assist in getting the fish back into a suitable depth.
Seafood Trails 