Assessment of a stocking program: Findings and recommendations for the Snowy Lakes Trout Strategy
|Assessment of a stocking program: Findings and recommendations for the Snowy Lakes Trout Strategy
Stocking is used worldwide as a management tool to establish new fisheries or to increase fish numbers following a decline. Trout and salmon are not native to Australia but have been stocked into rivers and streams since the late 1800s to establish and maintain a recreational fishery. Over the past 20 years, a total of 63,700,000 brown, rainbow and brook trout have been stocked into NSW. Despite such an intense stocking regime, there has been relatively little monitoring of the success of these stockings or evaluation of the status of trout fisheries.
In December 2000, a working Group was established to develop a strategy to manage the trout fisheries of three important fisheries in Lake Eucumbene, Lake Jindabyne and Tantangara Reservoir. A Snowy Lakes Trout Strategy was subsequently drafted to guide fish stocking practices in the region. The main recommendation was that rainbow trout be stocked into Lake Eucumbene (150,000 fingerlings) and Lake Jindabyne (50,000 fingerlings) on an annual basis.
To ensure the stocking was undertaken in a sustainable manner, a monitoring program was established to determine the relative success of these stockings. The program sought to monitor various aspects of the trout population to determine if the stocking practices were adequate. This report summarises the findings of that monitoring program, and provides additional recommendations about stocking levels to sustain the economic importance of trout fishing to the Snowy Mountains region.
Results from this five year study show that both rainbow and brown trout populations of Lake Jindabyne and Eucumbene are in excellent condition. Spawning fish were always in fair to good condition and the ratio of stocked to wild fish was always lower than 25% in all sampling years; an observation indicating that both wild and stocked fish are spawning in the systems. Information from angler catch returns also demonstrated that the recreational fishery is healthy, as angler catch rates were high, and varied little among years.
These data demonstrate that both rainbow and brown trout populations are performing well in both lakes and their associated tributaries. Stocking of rainbow trout should therefore continue at the present level as there are no signs of population distress in either waterbody. Brown trout should not be stocked, as the species has established a self-sustaining population since they were last stocked 20 years ago. Continuing to regularly monitor the annual spawning migrations would ensure the fishery remains healthy and that a viable recreational fishery is maintained.