Christopher Hallett

Chris Hallett’s project aims to develop a reliable, practical and cost-effective index for assessing the health of the Swan Estuary, based on fish assemblage characteristics.

Different aspects of the fish community – diversity and composition, use of the estuary as a nursery habitat and the trophic structure (the feeding relationships between species) – will be measured. Historical data collected between 1977 and 2004 is being used to construct a reference against which the future health of the estuary will be compared.

Managers and scientists will then be able to use a reliable but simple system to quantify and monitor the ecological health of the Swan Estuary, and monitor changes in its condition. Development of the index will create improved and more effective management of the Swan Estuary.

The project, funded by WAMSI, Murdoch University, the Department of Fisheries, the Department of Water and the Swan River Trust, involves the collation and analysis of fish community data collected seasonally over two years.

To date, sampling of the fish community of the Swan Estuary has been completed for six seasons out of the planned eight. Fish are collected from more than 20 nearshore and offshore sites. The former are sampled using seine nets, while the latter are sampled using sunken gill nets. All fish captured are identified to species and the total number of individuals of each species in each sample is recorded.

“The index will incorporate information on a range of fish community characteristics and will enable estuary managers to quantify estuarine health, monitor future changes in the condition of the Swan Estuary and facilitate more informed and preventative management actions. The index also represents a simple, easily understood method for communicating our science to the public and stakeholders. “

The work will assess whether the index for the Swan Estuary can be applied to measure the health of other WA estuaries using the Wellstead Estuary near Bremer Bay as a trial. If successful it will be a crucial tool for assessing and comparing the health of estuaries across south-western Australia.

Chris gained a BSc in biology from the University of Manchester, studying the effects of light on the health of Costa Rican tree frogs before commencing an MSc in Marine Environmental Protection at the University of Wales, Bangor. He held a volunteer research fellowship at CSIRO in Hobart to study the diet and feeding ecology of two deep-sea dogfish species on Tasmanian seamounts.

“I fell in love with Australia during my time in Tasmania, and so in February 2007, I began a PhD in the Centre for Fish and Fisheries Research at Murdoch University.”

Chris is working on WAMSI Node 4 projects. His supervisors are Dr Fiona Valesini and Professor Ian Potter. His thesis is entitled, Estuarine Health Index.

Presentations made at workshops and conferences

• National Estuaries Network Open Public Forum: Estuary Science for a Changing Climate, UWA, May 2007
• Australian Marine Science Association (WA)’s fifth annual student workshop at Rottnest Island, July 2007
• The Centre for Ecosystem Management Seminar Series, ECU, August 2007
• AMSA (WA)’s  sixth annual student workshop at Rottnest Island, July 2008