Fish assemblages in residential canal developments near the mouth of a subtropical Queensland estuary

Abstract

The hydrological conditions and fish fauna occurring in canal developments situated near the mouth of a subtropical estuary in southern Queensland were studied for 15 months from December 1985 to February 1987. In contrast to canal developments situated in bays or the middle reaches of estuaries, these downstream canals did not entrap sediments, and only minimal silt deposition occurred in those canals most isolated from the river. Hydrological conditions within the canals were generally within recommended limits for fish survival, although low oxygen concentrations in bottom water occurred on isolated occasions in the dead-end canals. The ichthyofauna of these canals, as in other canal developments, was dominated by planktivores/microcarnivores of no direct importance to fisheries. These fish guilds occurred in substantially greater numerical proportions in the canals than in undisturbed wetland areas. Well-flushed canals constructed in nontidal sandy areas are likely to have minimal impact on existing fish communities and could increase the area of available fish habitat. Extra keywords: canal design, hydrology, oxygen content, estuarine fisheries, coastal development.