Grow-out of Snapper (Pagrus auratus) in sea cages
Final report
The aim of this project was to farm, on a pilot commercial scale, two indigenous species of marine fish: snapper, Pagrus auratus; and mulloway, Argyrosomus hololepidotus.
The project involved:
- development of hatchery techniques;
- intensive rearing of larvae;
- transport of live fish;
- design, construction and testing of seacages for research;
- grow-out of juvenile fish in tanks and seacages;
- identifying and treating disease outbreaks in seacages;
- obtaining production data; and
- obtaining preliminary marketing information.
The project sought to provide information on the possibility of enhancing wild stocks of mulloway by the release of fish originating from a hatchery.
Enhancement of mulloway (Argyrosomus hololepidotus) in intermittently opening lagoons
Final report
Mariculture nutrition
Final report
Nursery culture of the sydney rock oyster saccostrea commercialis and the pacific oyster crassostrea gigas
Enhancement and farming of scallops in NSW using hatchery produced seedstock
Final report
This is a report on the second stage of a two part program investigating hatchery production, farming and seeding of the commercial scallop, Pecten fumatus. A total of more than four million scallop spat were produced for farming trials and over 250 000 scallops ranging in size from 20-60 mm were released into Jervis Bay.
Hatchery techniques were broadened to include procedures for the production of triploid P. fumatus. In general, the survival of triploid scallops was considerably lower than that of normal (diploid) scallops, particularly, immediately after treatment and during early larval rearing. No differences were observed between triploid and diploid spat, however, juvenile triploid scallops tended to be larger and heavier with significantly larger muscle tissues. The significant reduction in embryo development percentages (>80%), the relatively low percentage triploidy achieved initially (41%) followed by consistent reductions in percentage triploidy, mean that further research is required before it would be applied to the commercial sector.
Although our previous research had, for the first time, demonstrated reliable large scale rearing of P. fumatus larvae was possible, several major constraints to hatchery production were noted. Previously, larvae were either retained in the hatchery until they were large enough to be transferred to land based upweller systems, or larvae were settled on mesh in collector bags and transferred directly to the field. A new technique was developed in which larvae were settled on mesh screens held in the hatchery for about a fortnight before being placed in mesh bags at known densities and moved to the field for culture. This technique allows control of spat stocking density, and has produced threefold increases in spat yields over previous bag settlement techniques while significantly reducing maintenance costs.
KEYWORDS: Commercial scallop, hatchery production, farming, reseeding.
Evaluation of practical technologies for Perfluoroalkyl (PFA) remediation in marine fish hatcheries
Future Oysters CRC-P: Accelerated Sydney Rock Oyster (SRO) Breeding Research
Selective breeding for disease resistance and fast growth in Sydney rock oysters
The NSW oyster industry has suffered from QX disease and winter mortality for a very long time. It has responded to these disease challenges by vacating affected leases seasonally or in the case of Georges River by abondoning the infested part of the estuary. The history of inter-estuary transfer of oysters for on-growing has not allowed the development of resistant strains in NSW. However, if resistant strains of oysters are not developed, the industry will have no better management tool available in future than that used in the past, ie moving or selling oysters before a disease outbreak is expected or abondoning oyster leases.
If the opportunity for breeding QX disease resistance in Sydney rock oysters is not taken up, a unique opportunity will be lost, to use breeding lines previously selected for fast growth in the selection for disease resistance. It is important that breeding for QX resistance begins now, before another estuary is infested with this parasite. In Georges River, the industry responded to the QX outbreak by abandoning affected leases.
Growth rates in Sydney rock oysters have been improved by an average of 4% for the first generation of selection in Port Stephens. Now the initial progress has been made and four breeding lines are established, it is important that the momentum is maintained and selective breeding for fast growth is continued. The growth rate of the Port Stephens selection lines can be increased by 4% for each successive generation.
Growth rates in Sydney rock oysters can be improved by both selective breeding (an average of 4% faster growth for the first generation of selection) and triploidy (30-40% faster growth). However, triploids have not previously been produced from improved breeding lines. It is important to determine if improvements in growth rates by these two methods are additive. For example with triploids produced from improved breeding lines, a 30% increase in growth rate with triploidy plus another 8% for two generations of selective breeding may increase growth rates of oysters by 38%.