The farming of quality Australian abalone is a profitable industry, producing an estimated total ~1,000 tonnes live weight with a value of $35 million in the financial year ending July 2017. Notably, over the next 10 years, abalone production is forecast to increase by >300% to ~3,600 tonnes with an estimated total value of ~$120 million based on current day market prices. However, in order to facilitate this growth, detailed knowledge pertaining to the nutritional requirements of farmed abalone species is paramount. Currently, hybrid abalone culture is carried out via the provision of feeds developed specifically for greenlip abalone. While these feeds promote good growth and survival in both species, it is considered that the ideal protein ratio requirements of abalone may vary in relation to temperature (season), age (stage of growth) and species, (greenlip vs. hybrid). The issue is further exacerbated by varying, and site specific environmental conditions; especially high summer temperatures causing incidents of elevated mortality; and low winter temperatures suppressing growth. As such, on-farm performance of hybrid abalone has significant scope for improvement via nutritional intervention. Carefully planned and targeted RD&E effort that builds on the nutritional knowledge amassed for greenlip abalone therefore has the capacity to make rapid steps in relation to the productivity of the hybrid abalone aquaculture industry. Those gains are in turn expected to be transferable back to greenlip aquaculture.
The Australian Abalone Growers Association has identified ‘Nutrition’ as an RD&E investment priority in its 2015-2020 Strategic Plan, with a Strategic Goal to ‘Implement a Nutrition Program for Health, Survivorship and Meat Weight Gain’. This project will assist industry in achieving its projected growth within the time-frame of AAGA’s Strategic Plan by developing formulated feeds that are tailored to the major seasonal trends experienced by the abalone farming industry. Depending on the differences found in nutritional requirements this may result in the development of age/size-specific, temperature/season-specific and/or species-specific diets.
Final report
The Australian Abalone aquaculture industry continues to search for performance improvements in farmed hybrid Abalone (Haliotis laevigata x H. rubra) to satisfy increasing consumer demand. This project was the first in 25 years to comprehensively profile existing commercial feeds and found large differences in their nutritional composition. These results informed the experimental diets that were manufactured and trialled under the project.
Growth trials on sub-adult and juvenile hybrid Abalone showed that efficiencies in growth can be achieved by increasing protein to more than 40 per cent. In depth metabolic assessments overwhelmingly showed that increasing this level does not increase oxygen consumption in hybrid Abalone or reduce tolerance to oxidative stress caused by high water temperatures.
This project provides clear evidence to hybrid Abalone producers and feed manufacturers that increases in growth can be achieved by changing the composition of current diets and that implementing these changes does not compromise Abalone health during stressful summer growing conditions.
