Evaluation of a Sport Fish Stocking Program in Lakes of the Southern Murray–Darling Basin, Australia

Abstract

The golden perch Macquaria ambigua is a recreationally important freshwater sport and food fish species found throughout southeastern Australia. Stocking golden perch in impoundments has been used by fisheries managers to enhance existing wild populations for over 30 years. Despite widespread stocking, the contribution of stocked fish to golden perch populations has not been investigated. We evaluated the stocking contribution by using chemically marked golden perch fingerlings introduced into three lakes in which natural recruitment is low. We surveyed the lakes to determine the contribution of the stocked fish to the lake populations and found an overall contribution of 47 ± 9% (mean ± SE) at Reedy Lake, 55 ± 9% at Kangaroo Lake, and 90 ± 5% at Lake Charm. Our results indicate that, rather than replacing wild fish, stocked fish increased the abundance of adult fish at all three lakes. The contribution of stocked fish to each population declined with increased connectedness to the Loddon River, which served as the probable source for the wild fish population. Stocking programs can substantially augment fish populations when natural recruitment is very low.