Study of stocked mulloway fingerlings in NSW estuaries and identifying mulloway sites using tagged fish
Enhancing recreational fisheries through research into the responsible and optimal stocking of mulloway into estuaries
Saltwater Trust Allocation
2008/09 $52,509
Aim
To evaluate the ecological and genetic aspects of stocking mulloway in estuaries.
Background
Fish stocking supports some of our most important inland fisheries enhancing the recreational catch of anglers. However, there is insufficient information on the environmental aspects of marine stocking, such as predatory impact on small forage fish and prawns and the growth and survival of the stocked fish. Such aspects need to be thoroughly investigated and assessed according to environmental law before any large scale marine stockings can occur.
The University of NSW in partnership with NSW DPI is undertaking stockings in northern NSW estuaries and Botany Bay to refine release strategies which will optimise the survival and growth of mulloway in terms of fingerling size, release season and habitat. This will ultimately maximise the benefit of stocking for recreational anglers. An assessment of the genetic contribution/diversity of stocked and wild mulloway in these estuaries is also being undertaken.
This program is receiving widespread support from recreational fishers who recognise that it is a positive step toward replenishing fish stocks but that stocking should also be thoroughly investigated and assessed.
So far the following stockings have been undertaken in:
2006
|
Location |
Number stocked |
|---|---|
Botany Bay/Georges River |
14,000 |
Manning River |
20,000 |
Tweed River |
21,500 |
Richmond River |
15,000 |
2007
| Location |
Number stocked |
|---|---|
Botany Bay/Georges River |
14,000 |
Manning River |
20,000 |
Saltwater Trust Allocation
2007/08 $129,750
Aim
Assessment of the dispersal response of stocked fish when stocked at modeled optimal, and at higher, non-optimal densities, using acoustic telemetry.
Background
Ultrasonic tags will be used to track newly released mulloway in the Georges River. Model simulations will be performed to estimate optimal stocking density for four deep holes with similar salinities within the river. Fish will be stocked at a size of 20cm (instead of the usual target size of 8 cm) to facilitate attachment of an acoustic tag.
