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Fish barrier removal and river connectivity support glenelg river tupong populations

Tupong are a migratory native fish that inhabit estuaries, creeks and rivers, including the Glenelg River. Connectivity is thought to be a major factor influencing the health of the species, as Tupong require access to the sea and freshwater to complete their lifecycles. Increases in river flow in spring and summer are thought to stimulate the movement of young Tupong from the ocean into coastal rivers and further upstream into freshwater reaches. Maintaining suitable freshwater habitat is critical to ensure the fish have sufficient habitat and food resources to feed, grow and breed. Adult Tupong then migrate back to the estuary or sea to spawn on large winter freshes. Annual fish monitoring, from 2009 to 2018, coincided with the removal of 12 fish barriers along the Glenelg River. The fish monitoring showed tupong numbers have increased substantially in recent years and their range is now well over 300 km throughout the Glenelg River. Record numbers of young Tupong were recorded moving upstream from the estuary to the freshwater reaches in the most recent fish surveys (2018). This highlights the importance of removing fish barriers and connecting the Glenelg River with water for the environment as regulated base flows. The removal of these fish barriers has opened up 977 km of waterways to fish movement in the Glenelg Catchment. Along with complementary works including reinstatement of instream woody habitat and the return of water for the environment, fish barrier removal has played an important role in supporting healthy populations of not only Tupong but other fish species in the Glenelg River.