Barriers to Protect Threatened Fishes
Whilst improving fish passage is valuable and often essential tool to rehabilitating native fish populations, there can also be the unintended consequence of facilitating the passage and spread of undesirable alien fish that are known to have devastating impacts on certain threatened fish species. Similarly the blockage of fish passage to limit or stop the spread of alien fish into new habitats can be a useful tool in the protection of remnant populations of vulnerable threatened native fish species.
We provide three separate case studies of where barriers, both constructed and natural have been used to protect remnant populations of two threatened fish species in NSW, from recent invasions of alien fish species, a fourth case study will be included, where we have designed and propose to construct a significant fish passage barrier, then remove alien fish upstream of that barrier with the aim of reinstating and expanding a population of threatened native fish.