Restoring the Onk at Perrys Bend

OzFish Onkarapinga Chapter members recently completed stage one of their project to restore their local river. The group deployed an impressive 180 limestone blocks into the ‘Onk’ as part of their plan to improve fishing in the river.

Like many Australian rivers, the Onkaparinga has a long history of degradation and neglect, but the Chapter are determined to turn that around. The group hopes to reduce and reverse the impacts of erosion by planting trees along the river bank, installing snags (woody debris) and building new substrate with limestone concrete blocks. 

Early sounding results and observations have shown that fish are using the area already. With very little structure left in the river, fish have been congregating around the new habitat. It is also anticipated the limestone blocks will soon be colonized with mussels, barnacles, coraline tubeworms and oysters. It is hoped the limestone surface will imitate the natural surface of a shellfish reef, thus enabling these invertebrates to take hold.

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During stage 2 of the project the Chapter plans to replace the ‘missing critical component’ of snags along shoreline. As with the limestone blocks the snags should reduce erosion, provide shelter for fish and give other small life forms a surface to get a foot hold and grow.  Stage 3 will involve replanting the now barren river banks.

The Chapter would like to thank OzFish Unlimited, RecFish SA and the Recreation Fishing Grants Programme for their contributions in making the project possible.

For more information: Fishers Tackling Fish Habitat Issues in the Onk