SCRC: Improvements in Yellowtail Kingfish larval and juvenile survival and quality
Yellowtail Kingfish culture is a rapidly expanding industry in Australia, particularly in rural South Australia, where it is driving the increase in the ‘other’ category of aquaculture production from ~1100 tonnes valued at ~$9 million in 2002-03 to 2000 tonnes and $17 million in 2004-05 (ABARE, 2006). Regarding future production, CST alone are projecting an increase in annual production towards 8,000 T by 2015.
CST is the largest producer of Yellowtail Kingfish in Australia having produced over 1.25 M juveniles in 2007. The company operates two Yellowtail Kingfish hatcheries at Arno Bay and Port Augusta. The production of quality larvae from hatcheries underpins the production of farmed fish and low survival and high levels of malformations significantly increase costs.
Survival of Yellowtail Kingfish juveniles in Australian marine hatcheries is very low in comparison to many other marine species such as sea bass and bream produced in larger more mature industries, for example in Europe. Of particular note, several skeletal malformations have been reported in Australia and New Zealand, although few are well documented (Yellowtail Kingfish, Cobcroft et al., 2004).
There is also high variability in hatchery survival rates and the rate and severity of deformities among production runs and commercial hatcheries.
By way of illustration, the direct benefit to Clean Seas Tuna Ltd. of reducing malformations in Yellowtail Kingfish is estimated to be $1 million p.a. In this example a reduction in malformations from 40% to 20% (on 2.0 M juveniles before quality grading) could produce a further 400,000 good quality juveniles @ $2.50 (market value) = $1,000,000.
Final report
This project consists of nine research projects addressing nine objectives set out in the overarching program of activity described in project 2007/707. The nine projects collectively endeavour to resolve the larval rearing, juvenile development and productivity constraints for propagated Southern Bluefin Tuna, Thunnus maccoyii, as well as continue to make improvements to the production of Yellowtail Kingfish, Seriola lalandi (YTK). The activities described in this report refer to the research that aims to increase survival rates of YTK larvae to more than 25%, and reduce malformation rates to less than 10% before hatchery grading.
