Oral Presentation International Conference on River Connectivity (Fish Passage 2018)

How low do we go - Advances in fish passage technology for small fish (<100 mm long!). (#94)

Tim Marsden 1 , Ivor Stuart 2
  1. AFPS, Fern Bay, NSW, Australia
  2. Kingfisher Research, Melbourne, Victoria, Australia

In Australia, provision of fish passage has often focused on adult and sub-adult fish of a number of iconic species such as Murray cod, golden perch, barramundi and mullet. However, there is a diversity of species whose post larvae juveniles make upstream migrations from the estuary into lowland freshwater habitats in Queensland. This includes: empire gudgeons, long-finned eels, bony bream, anchovies, mangrove jack, striped mullet and barramundi have juveniles that are very small when entering freshwater. These fish, as small as 8 mm long, encounter stream barriers and successful passage is crucial to maximising survival and productivity. In extreme cases barriers, can completely block these life stages and lead to a freshwater population collapse. Providing passage for small fish has required a rethink of traditional fish passage options, now there is a renewed focus on very low turbulence and roughened fishways that create hydraulic micro habitats that these fish use to move upstream. We outline the design options available for passage of small fish and successful fishways in Queensland.