An inventory of impediments to tidal flow in NSW estuarine fisheries habitats

Tidal flow is thought to be an important consideration in the maintenance of fish habitat, particularly nursery habitat. To assess the presence of structures which impede tidal flow in New South Wales, a special project was initiated in mid 1994 which collected anecdotal and field data. The former were collected via a questionnaire sent to Oyster farmers and fisheries officers, while the latter were preceeded by the inspection of 148 1:25000 topographic maps. The presence of bridges, culverts, causeways, fords, weirs and floodgates were noted on the maps. Nearly 4230 structures located in the tidal zone were considered for their remediation potential, and we suggest 1388 are candidates for change. The majority of the candidate structures are floodgates, almost 50% of which occur in three north coast rivers. The information obtained in this inventory has important implications for habitat managers and researchers in NSW and the other Australian states.