As concern increases over the future health of the Great Barrier Reef, the emerging prawn farming industry joins the Wet Tropics Healthy Waterways Partnership and suggests switching to more sustainable crops in coastal areas of the Wet Tropics
Prawn farming in Australia is still a relatively small industry, even after 30 years of supplying quality Australian seafood. Almost half the industry resides in the Wet Tropics where six active farms produce 2,000 tonnes of prawns each year. They employ 177 full time staff in small regional communities (Cardwell, Macknade, Mission Beach, Kurrimine and Mossman) and add $38.2 million to the Queensland economy.
And the industry is growing with the Douglas Shire Council recently approving a multi-million dollar expansion of the Mossman farm, which will double its capacity.
Interestingly, the dollar yield per hectare for prawn farming is well above traditional terrestrial agricultural uses. The six farms in the Wet Tropics who are farming 295 hectares can return $129,491 in dollar value per hectare of farmed land, all within a six month grow out period.
The industry is keen to see more investment in prawn farming and sees the Wet Tropics as a potential growth area. Given its environmental credentials, they also want to highlight prawn farming as a more sustainable use of agricultural land.
Prawn farms are strictly regulated in terms of what can be discharged and the industry is one of the few to have a point source discharge where part of their license conditions to DAF and EHP requires continuous analysis, testing and reporting.
The Australian Prawn Farming Association (APFA) says that a 2003 research paper published in the Marine Pollution Bulletin confirmed what they already knew - prawn farms in an estuarine environment are not a large contributor to loads reaching the reef. It was found that nutrients released into the estuarine environment were not detectable 2kms downstream.
While prawn farms are strictly regulated they are not able to control the quality of the water that comes into the farm. Larger farms pump water from the estuaries into a large settlement system and nutrients, sediments and chemicals all have an effect on the life of a prawn just as it affects the Reef.
Once production starts farms constantly monitor dissolved oxygen, temperature, salinity, total ammonia nitrogen (TAN), Nitrite (NO), alkalinity, turbidity and pH. Monitoring and knowing algal blooms is also critical for a successful healthy crop.
Keeping prawns alive requires constant monitoring of the environment and weather conditions to maintain healthy ponds, combined with the complexities of keeping the feed doses correct and adding the right amount of aeration.
According to the AFPA, water quality is a key research priority for the industry and its growing economic success prompted a “comprehensive, multi-disciplinary study of intensive impacts on downstream environments and the development of cost effective effluent treatment systems”.
The seven year study (1995-2002) focussed on the largest prawn farms in Queensland and New South Wales throughout the production cycle over successive years and produced 46 peer reviewed research papers for ponds, pond discharge composition, treatment and environment management, receiving waters – assimilation and monitoring and land mapping.
The industry is continuously looking for ways to improve the sustainability of its farming practices.
Joining the Partnership
As an industry committed to sustainability the AFPA considers joining the Wet Tropics Healthy Waterways Partnership an important move and one that will hopefully help build their connections with the community while putting a spotlight on the industry’s environmental credentials.
Go to www.australianprawns.com.au for some great prawn recipes.