Thousands of physical barriers around Australia limit the ability of fish to migrate.
Unlocking paths for fish
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To determine whether a fishway is functioning as intended, OzFish Unlimited assess a range of factors, including the number of species passing through, the size of fish, water quality and water velocity.
HEN we’re out fishing, most of the fish we catch – and many we don’t – need to migrate at some point in their lifecycle, due to resource limitation or to breed. Around Australia, there are thousands of physical barriers to fish movement and passage, limiting the ability of fish to migrate, reducing the total amount of habitat available and placing further pressure on fish stocks that are often already under stress. Some of our fish migrate strictly within
freshwater environments, however many also need to migrate between freshwater and saltwater habitats. To take an example from the rivers and wetlands of north Queensland, barramundi, mangrove jack, tarpon and jungle perch migrate between freshwater and saltwater at least once as part of their lifecycle. These are the more visible species because they’re popular for recreational anglers, yet many of the smaller species that underpin the food chain – including many of the gobies and gudgeons – need to undertake similar migrations. In an ideal world, we would simply remove all the barriers to fish passage and restore the hydrology back to its original state, however this is rarely possible or feasible.
In most cases, the physical infrastructure contributing to this issue is essential for things such as transport, water storage and municipal stormwater conveyance. Fishways provide a solution to this issue by retaining the function of essential infrastructure, while also providing passage for fish. Fishways come in all shapes and sizes, and their design depends on the location and height of the barrier. For instance, a fishway built on a large dam or weir will be very different in design to a fishway built at a small culvert or causeway. In practice, most of the physical barriers to fish passage are small (that is, a vertical drop of <1m), and therefore many of the fishways we see in places such as coastal north * continued P75
JOIN THE MOVEMENT
CREATING BETTER HABITAT FOR BETTER FISHING Page 74 – Bush ’n Beach Fishing, May 2024
Fishways provide a solution by retaining the function of essential infrastructure while also providing passage for fish.
www.bnbfishing.com. au
