Improving Fish Habitat

Can a small fish make its way up the rivers and tributaries in the Lower Barron, Mossman and Daintree catchments? That’s the basis for a project that’s assessing if infrastructure like weirs, dams and culverts are stopping fish moving upstream to nursery and breeding grounds.

These river catchments are hotspots for diadromous fish species like barramundi and jungle perch – adults spawn in estuaries and juvenile fish migrate upstream to freshwater habitat where they mature into adults.

More than 1600 potential barriers have been identified as part of a new project aiming to improve recreational fishing outcomes by improving waterway habitat connection.

Terrain NRM’s Lana Hepburn explains that a number of factors determine which barriers would be most beneficial to remediate to get good recreational fishing and ecological outcomes.

“The goal is to open as much habitat upstream as we can, so we look at where the barrier is in the catchment. If it’s closer to the coast it’s potentially blocking more upstream habitat – so the distance between each barrier is important too.

“We also look at how connected a waterway is to the ocean. Barriers in rivers that connect to the ocean would be prioritised over small tributaries that flow into different creeks and rivers before hitting the ocean,” Lana said.

Some barriers are only obvious in low flow conditions during winter, but fish need to be able to migrate at different times of the year.

A field team from Terrain NRM, Wet Tropics Waterways and Dawul Wuru Aboriginal Corporation’s Yirrganydji Land & Sea Rangers have now physically inspected hundreds of barriers to assess their priority for remediation.