Some Aspects of the Ecology of Lake Macquarie, N.S.W., with Regard to an Alleged Depletion of Fish. I. General Introduction

Abstract

In the period 1883-98 Lake Macquarie was the principal source of fish for Sydney and Newcastle. Since 1930 it has been only tenth or eleventh of New South Wales estuaries in fish production. The number of commercial fishermen in 1920 was 110, but today is only 35. Allegations of depletion prompted this investigation, the results of which are discussed in this series of papers. Lake Macquarie is a coastal lake with a small freshwater inflow estimated to be only 4 per cent. of its volume. Attempts to improve the channel connecting the lake with the sea have failed repeatedly. A seemingly permanent result of the dredging is a great enlargement of the unproductive sand flat at the inner end of the channel. The soils of the lake's catchment area are poor in minerals. The land vegetation is mainly sclerophyllous forest with isolated patches of rain-forest and Melaleuca swamp. The population has increased since the first settlement in 1825 until it is now over 50,000, but the lake is also a recreation area for the much larger population of Newcastle (over 200,000).