Use of Float-Tubes to Increase Efficiency and Safety of Backpack Electrofishing in Australian Isolated Boulder Streams

Backpack electrofishing is arguably the most time-effective and least selective sampling method for assessing freshwater fish populations in small streams. However when these streams are situated in isolated gorge locations, the habitat often consists of deep pools dispersed with shallow boulders and bedrock. Sampling efficiency and safety of staff and equipment are often substantially reduced due to limited safe wading access to fish habitat. Other sampling methods are usually unsuitable due to site isolation and difficult access (limits to the size and weight of equipment that can be carried for long distances and into steep gorges) and time constraints (amount and type of sampling that can be conducted during one day minus portage time). An innovative float-tube system was devised to improve safety and increase access to deep-water habitat, and the devices were used in conjunction with backpack electrofishing to assess populations of the endangered Macquarie perch in streams of the Blue Mountains, NSW Australia.