Some Aspects of the Ecology of Lake Macquarie, N.S.W., with Regard to an Alleged Depletion of Fish. VII. The Benthic Macrofauna.

Abstract

The benthic zone of Lake Macquarie, passing from shallow to deep water, consists of weed, slope, and mud zones, occupying respectively 23.5, 16.0, and 60.5 per cent. of the lake area. The biomasses of the invertebrate macrofauna of the zones are respectively 94 156 g, 180 ± 12 g, and 10.6 ± 9.4 g per m2. Each zone has its typical fauna. A variety of species occurs in the weed and slope zones, but only two species occur in number in the mud zone.

A number of mollusc species was represented only by dead shells of recent origin, suggesting some catastrophe such as production of anaerobic conditions. There is no evidence that the mussel Trichomya hirsuta was affected, and experimentation revealed that this species can survive long periods of immersion under anaerobic conditions.