Summary

NSW DPI has been undertaking surveys of carp populations within NSW.  This work has included sampling for both larval and adult fish in order to: determine ‘hot-spots’ of carp breeding; benchmark the sex ratio throughout NSW and collect DNA samples for genetic population structure assessment; assess spatial and temporal variation in reproductive condition throughout NSW and assess spatial variability in population dynamics.  The results of sampling undertaken to date suggest that:

1) Carp breeding is not widespread but is generally restricted to large wetland systems in the lower parts of catchments and large impoundments.

2) The sex ratio is not a uniform 1:1 ratio throughout the Murray-Darling Basin, with a general pattern of female-dominated populations in the north and male-dominated populations in the south.

3) There is little spatial variability in carp breeding, and widespread spawning occurs in both Spring and Autumn.

4) There is limited recruitment of carp in isolated coastal populations suggesting that these populations may die out in many small catchments over the next decade.

This project continues to provide insights into the ecology of invasive carp.  With this and additional information anticipated to be gained from the project, there will be a very sound basis for the design of integrated pest management approaches.  The current project is restricted to NSW, but it will be implemented across the entire Murray-Darling Basin under a new CRC (the Australian Invasive Animal CRC), which comes into effect in July 2005.