Scientists from Arthur Rylah Institute for Environmental Science (ARI) found the grayling while undertaking fish monitoring for the Native Fish Report Card program. The adult fish was safely returned to the river.
Once abundant throughout the coastal rivers of south-eastern Australia, Australian grayling populations have declined due to altered river flows, water extraction and barriers to fish movement such as weirs. Grayling need certain types of flows at different times of the year to trigger and enable breeding migrations between freshwater and the ocean. Adult fish need to move upstream to spawn, while juveniles require suitable flows to move downstream into nursery areas in estuaries and the ocean.
ARI research in Victorian coastal rivers shows that Australian grayling benefit from flow pulses or ‘freshes’ to stimulate spawning migrations. That’s where we come in – managing delivery of water for the environment to the regulated Glenelg River. Returning flows to the Glenelg at the right rate, time and place helps to keep river habitats connected for fish that need to move about. Estuary perch and black bream also rely on flow cues for spawning and recruitment.
An environmental ‘fresh’ is currently moving through the upper Glenelg River to keep it healthy and fish moving freely.
The Native Fish Report Card program - supported by Department of Environment, Land, Water and Planning and Victorian Fisheries Authority - monitors fish populations annually.
Photos courtesy of Arthur Rylah Institute for Environmental Science (ARI).