Movement of large bodied fish in response to water management at the Hattah Lakes
August 2014 to June 2017
Hattah Lakes are part of the 48,000 hectare Hattah-Kulkyne National Park located in the north west corner of Victoria, Australia. The system comprises of 18 semi-permanent freshwater lakes which receive water from the Murray River via a feeder creek; Chalka Creek. The lakes start to fill when flows in the Murray River reach a critical level where water spills into Chalka Creek.
Decreased flooding frequency of the Hattah Lakes due to river regulation resulted in a recent works and measures program to reinstate more frequent flooding. The program resulted in the installation of a pumping station, series of regulators and a number of block banks which allow more than 6000 hectares of the Hattah Lakes National Park to be artificially flooded (equivalent of 45 m Australian Height Datum). These structures allow control of the water regime in Hattah Lakes, in line with seasonal cues and water availability.
Acoustic tracking technology is used worldwide to study fish movements. A tag is surgically implanted in a fish. This tag emits a high frequency, unique identifying code that is detected by receiving stations when the fish is in range. Receivers are set out either in a grid pattern or at strategic locations (e.g. river junctions) that increase the chance of detecting tagged fish. The acoustic receiver array time and date stamps the signal and this data is saved. Once downloaded, the information can be analysed such that a model of fish movement can be created which may help in answering particular questions.
Carp are a common pest species in Hattah Lakes (and nationally). The initial phase of this project is to tag carp with acoustic tags and assess their movement patterns within Hattah Lakes. In particular we aim to link carp movement to changes in water level in the lakes. This information will be used to better control and manage carp in Hattah Lakes (and elsewhere) in the future. The second phase of this project will involve tagging Golden perch in Hattah Lakes to determine their responses to changes in water level. This will provide information that may assist the management of Hattah Lakes for native species.
The main objective is to understand fish responses to a range of flow scenarios in the Hattah system to advise future management of watering events.
Operational objectives include: