Baumgartner L, Cameron L, Faragher R and Pogonoski J (2008) An assessment of the trout fishery in Oberon Dam and the Fish River. NSW Fisheries Research Report Series No. 19. 23 pp. ISSN 1440-3544.

Summary

Oberon Dam is a water storage of 45,390Ml located 200km North West of Sydney. The dam was constructed in 1949, and impounded the upper sections of the Fish River Creek in New South Wales. Approximately 990,000 brown and rainbow trout have been stocked into Oberon Dam since 1980. Since 2000, the lake has been annually stocked with 20,000 rainbow trout from the Gaden Hatchery. The only recorded stocking of brown trout (n=5,000) took place in 1998. Annual spawning migrations of trout into the Fish River Creek were assessed between 2000 and 2007. The primary aim of these surveys was to identify if there were any changes to the trout populations that might require management intervention to prevent a collapse.

Results demonstrated that annual spawning runs of rainbow trout were exclusively wild fish, with no stocked fish captured over the study period. This observation suggests that natural recruitment is dominating fish production in the Fish River Creek. Analysis of size class information revealed the presence of juvenile cohorts in each year, suggesting that some degree of recruitment occurred annually. Larger size classes were also present, and were of ‘good’ to ‘fair’ condition. Both of these observations suggest the rainbow trout population is in a relatively healthy condition but is not particularly reliant upon stocking.

Brown trout have not been stocked since 1998 but a broad range of size classes were collected during the study. Strong year classes of juvenile fish were observed in four out of seven years and large adults migrated annually. Fish were in ‘good’ to ‘fair’ condition during the spawning migration and the population appeared to be in good health. Given the length of time since stocking, the brown trout population currently appears to be self-sustaining. Assessments of both trout populations in the Fish River Creek demonstrate a strong natural recruitment of both species. Whilst recruitment may not occur each year, it appears that existing levels are sufficient to maintain an effective fishery.