The unimpeded passage of fish throughout streams is crucial for spawning migrations, re-colonisations, general movement and habitat selection. Seventy percent of native fish species in Victoria's coastal drainages need to migrate to or from the sea at some stage in their life cycle. (From J.D Koehn & W.G.O'Connor 1990. Biological Information for Management of Native Freshwater Fish in Victoria. Dept. Conservation & Environment). Some species such as eels need to move out to sea to spawn.
Others, such as the short-headed lamprey, need to run up from the sea into fresh water to spawn. Many species such as the common galaxias and tupong, run down into the estuary to spawn and then the young juvenile fish need to be able to return upstream. Some fish spawn in the fresh water but their larvae are washed into the estuary and the juvenile fish then need to return upstream into fresh water. Unfortunately over the last 200 years a multitude of barriers have been constructed in our rivers. They range from low barriers at flow gauging stations, causeways and road crossings to dams, weirs and drop structures.
A total of 1,145 barriers are present on rivers north of the Divide and 1,293 barriers occur on coastal streams. In the late 1990's a 'Fishway Program' was commenced as a joint project of the Murray-Darling Basin Commission and the Department and the construction of fishways was funded by these, and other authorities, including Melbourne Water. By December 2002, a total of 58 fishways had been completed on 32 rivers, opening up a total of 4,465km of new sections of river to migratory fish.
This will extend the distribution of many species, increasing their number and allow them to colonise new habitat thus providing additional protection for the long-term survival of species. It will also extend the distribution and possibly abundance of migratory angling species such as Australian bass and golden perch as well as fish such as Murray cod which undertake extensive upstream migration to spawn. Fishways are therefore of great value for both conservation and recreational reasons. Sites for another 14 fishways are currently under investigation. Further information on the State Fishway Program is available from The Waterways Unit, DSE, Melbourne (9412 4050).