Prawn farms under pressure may find a saviour in mulloway
20 Feb 2012
Northern NSW prawn farms struggling to compete with cheaper imported prawns may have found a saviour in the popular ocean fish, mulloway.
A Rural Industries Research and Development Corporation-funded research trial has shown that the temperate marine species, mulloway – otherwise known as jewfish – can be successfully farmed using the infrastructure of existing prawn farms.
The research project, which was led by Dr Jeffrey Guy at Southern Cross University’s National Marine Science Centre, took a “pond-to-plate” approach which covered the breeding of mulloway fingerlings, growing the fish out to market size and testing the quality of the final cooked product.
The research trials were conducted on an existing prawn farm at Palmers Island near Yamba, NSW, however the findings could apply to any land-based aquaculture facility on the NSW north coast where the growing conditions suit mulloway.
Dr Guy said it is hoped the mulloway research trial will help encourage some of the larger Palmers Island prawn farms to diversify their production base and improve their longer term viability.
“Our research has shown that mulloway perform extremely well in prawn ponds, reaching market size in two years, with high survival, good growth, minimal disease and high production rates approaching 14 tonnes per hectare,” Dr Guy said.
“We also found mulloway to be a hardy species when grown in earthen ponds; they were very resilient to periods of poor water quality and no significant outbreaks of disease were recorded, so this may be the preferred culture environment for this species.
“Other positive findings were that the mulloway were easy to harvest and transfer - a major advantage in the farming of this species - and were extremely well received in the marketplace.”
Analysis of the farmed mulloway fillets showed they were an excellent source of long chain omega-3s and also contained high levels of the monounsaturated omega-9 fatty acid, oleic acid, providing important health benefits for consumers. Sensory evaluation of the cooked mulloway fillets found they were “quite acceptable” to over 60 percent of consumers that tasted the product.
Although the initial research findings are encouraging, the project also identified several factors that may limit the expansion and profitability of mulloway farming. Key constraints include a lack of knowledge about diets, feeding protocols and the effects of environmental parameters, such as temperature and salinity, on feed intake. The research trial also identified the poor availability and high cost of juvenile fish for grow-out. A new RIRDC-funded research project commenced earlier this year to look at the major cost areas of diets, feeding and fingerling production.
Globally, aquaculture is expected to play a crucial role in compensating for declining ‘wild’ capture fisheries and in meeting increased demand for high quality protein. Total aquaculture production in 2008 (the latest available figures) was 55.1 million tonnes with a value of US$98.4 billion, contributing around 38 percent of total global fisheries production and 46 percent of total food fish supply.
The “Re-invigorating NSW prawn farms through the culture of mulloway” publication can be downloaded for free from www.rirdc.gov.au.
Damon Whittock – RIRDC Public Affairs Manager – 02 6271 4175 or 0458 215 604.