2012/723 Performance of Barramundi from widespread genetic sources in diverse grow out environments

By Gavin Partridge

The project related to the WA Fishing Industry Council's 2020 Strategy of increasing aquaculture production to 50,000MT worth $500 million. This project was needed to identify whether GxE interactions occur in barramundi in order to design an appropriate barramundi breeding program/s. Such programs will lead to significant increases in production and profitability through improvements in growth and other heritable characteristics.

CRC research to date has laid the foundation for the development of a breeding program through business planning and measurements of existing genetic diversity within Australian. A strong understanding now exists on the levels of genetic diversity in both wild and captive stocks and how this diversity can be managed within a breeding program. Prior to a breeding program commencing, however, an important unanswered question remains as to which stocks perform best under commercial production environments and whether the best performing stocks in one environment are also the best performing in other aquaculture environments.

This project aimed identify the most appropriate strain of barramundi for seacage culture in northern Australia to ensure the long-term economic viability of the country’s largest barramundi producer and to enable other enterprises to establish in this region. On-farm and laboratory data demonstrates that significant differences in growth rates exist between strains in this farming environment. With growth rate being the key determinant to farm profitability, identifying the most appropriate barramundi strain for optimum performance across the wide temperature regime that exists in this farming environment (~22 to 32°C) is critical for the health of the farmed stock and the long term economic viability of the industry. Given that the barramundi industry recognise the importance of selective breeding to improve their profit & sustainability, this data will also be directly relevant to any future breeding program that may be developed.

Project Objectives

1. To conduct simultaneous mass-spawnings of two different barramundi strains
2. To ship juvenile barramundi from mass-spawned broodstock to two commercial farmsrepresenting diverse grow-out environments.
3. Determine whether genotype by environment interactions occur in key production parameters bymeasuring growth and condition indices at harvest on each farm
4. Determine whether genotype by environment interactions occur in fish quality by measuring keyquality indices at harvest
5. Make recommendations on the composition of founding broodstock populations and performanceevaluation systems for a national breeding program.
6. To determine how temperature effects the growth of each barramundi strain in seacages