Project Background

Objectives

1. To evaluate the utility of a RIVPACS-type approach to estuarine health assessment (ESTPACS) using suitable existing benthic macrofaunal data sets if available, and to investigate the appropriate level of taxonomic resolution to be used in a standard protocol.
2. To evaluate the ABC (abundance-biomass comparison) method of health assessment if suitable existing data are available.
3. To collect new data from estuaries in NSW and Victoria to support a demonstration ESTPACS model(s).
4. To develop a nationally applicable standard protocol for estuarine health assessment using benthic macrofauna.

Direction

The project collates and assesses the value of existing information about estuaries along the southeastern coast of mainland Australia with a view to establishing a protocol for national estuarine health assessment. In under tasking the project new information on the distribution of fauna in southeastern Australia estuaries was collected, and a database on the structure of southeastern Australian estuarine benthic community structures developed. This database can be used to assess long and short term changes to estuarine health.

Sampling Design

For developing and testing the RIVPAC type model 92 sites in 29 estuaries throughout Victoria and southern New South Wales were sampled. Usually three sites per estuary were sampled. Sites were selected to sample diverse habitats in each estuary and usually a lower, mid and upper estuarine site was sampled.

Two methods were used to collect benthic fauna from each location a dredge sample

Taking a biological sample of estuarine waters.

and a composite sample of five Ekman grabs (15 x 15 x 15 cm). In addition data were collected on a number of physical and chemical variables either measured at the site, obtained from a sediment sample (a separate 15 cm Ekman grab collected at the same time as the biological samples), or read off maps.

In additional temporal studies have been made of 11 sites in four estuaries spread across Victoria and southern New South Wales, the Hopkins (3 sites, western Victoria), the Darby (3 sites, central Victoria), Wingan Inlet (3 Sites, Eastern Victoria) and the Clyde (2 Sites, southern New South Wales). For this study seasonal samples of 10 replicate 15 cm Ekman grabs were collected. These samples were used to look at temporal differences in species composition and community structure to determine the most appropriate time of year for sampling.