Factors required for the successful aquaculture of black bream in inland water bodies - extension to project 1997/309
From the information in B2, there is, for the following reasons, clearly a need to develop a recreational inland fishery in south-western Australia utilising the euryhaline black bream. 1. To provide, for local residents and tourists in rural areas, access to an outstanding angling and food fish species that occurs naturally in Western Australia and which is both hardy and adapted to living in a wide range of salinities and temperatures. 2. To increase for rural areas, which, during recent years have suffered economic decline through land degradation and salinisation, the potential for tourism. 3. To reduce the fishing pressure on natural populations of black bream, the abundance of which in some estuaries has declined precipitously during the last 20 years, presumably through overfishing (FRDC 93/082). 4. To determine whether the very different growth rates recorded for geographically isolated natural populations of black bream are due to genetic differences or differences in the environments in which they live. Such data are important for ascertaining whether it is necessary to select carefully the populations used as broodstock. 5. To explore the possibility that inland water bodies could be used for producing black bream economically on a limited commercial scale. 6. To provide an angling species in inland saline water bodies of south-western Australia which occurs naturally in the region.
1. The ultimate objectives of the proposed study are to determine the suite of conditions, in inland water bodies, that are required for rearing black bream to a size that is suitable for angling and to be able to demonstrate to potential stockers of black bream that such fish can then be readily caught on rod and line. This information will also be invaluable to those property owners who, in the future, wish to use their properties for producing small amounts of black bream for commercial puroposes. The above overall objectives will be attained by achieving the following individual objectives;
2. Determine the relationship between the relative abundance and types of potential food that are naturally present in inland saline water bodies and those that are ingested by different sizes of black bream.
3. Determine whether yabbies constitute an appropriate live food source for particularly the larger black bream and where appropriate, self sustaining populations of yabbies can either established in inland water bodies or provided in a cost effective manner.
4. Determine, under controlled laboratory conditions, which of the currently available commercial fish feeds lead to optimal growth of black bream, and then, using the most cost effective of these feeds, determine the appropriate rate of feeding under field conditions over an extended grow-out period (12 months).
5. Determine the effectiveness of introducing underwater cover to reduce the predation of black bream by cormorants in inland water bodies.
6. Determine the effectiveness of using cages to house young black bream until they reach a size at which they are far less susceptible to predation by cormorants.
7. Determine whether the very different growth rates of black bream in the Swan and Moore River estuaries are paralleled by comparable differences when black bream from these two systems are cultured in the laboratory under identical salinity, temperature and food conditions.
8. Determine whether black bream are able to spawn successfully in inland water bodies and, if so, the broad characteristics of those water bodies where spawning occurs.
9. To provide information to farmers that will enable them to grow black bream successfully and thus constitute an extra source of revenue through charging for access to fishing on their land.
Principal Investigator: Sarre G.A., Partridge G.J., Jenkins G.I., Potter I.C. and Tiivel D.J.