Changing food habits of Macquarie perch, Macquaria australasica Cuvier (Pisces : Percichthyidae), during the initial filling phase of Lake Dartmouth, Victoria

Abstract

The composition of the diet of Macquarie perch changed markedly during the various stages of rising and falling water-level during the initial filling phase of Lake Dartmouth, an impoundment formed by the construction of Dartmouth Dam on the Mitta Mitta River in north-eastern Victoria. Macquarie perch fed on typical river-dwelling organisms from inflowing rivers, on terrestrial organisms that became displaced as the water-level rose, and on typical still-water or sluggish-water organisms, which were extremely abundant in the newly created lake. The relative proportions of several of these food types in the diet varied depending on whether the water-level was rising or falling. Macquarie perch appear to have adapted well to the changing food supply in the lake, and have included in their diet several food types that they would not normally have encountered in their natural riverine habitat.