Filming and Snorkelling as Mobile Visual Techniques to Survey Tropical Rainforest Stream Fauna (#31)
Dense tropical rainforest, waterfalls and shallow riffle-run-pool sequences pose challenges for researcher access to remote reaches of streams for aquatic fauna surveys, particularly when using capture-based collecting techniques (e.g. backpack and boat electrofishing, trapping). We compared the detection of aquatic species within pool habitats of a rainforest stream obtained by two mobile visual techniques during both the wet and dry season: active visual survey by snorkelling and baited remote underwater video stations (BRUVSs). Snorkelling detected more species than a single BRUVS at each site, both within and among seasons. Snorkelling was most effective for recording the presence and abundance (MaxN) of diurnally active small-bodied species (adult size <150 mm total length), although both techniques were comparable in detecting large-bodied taxa (turtles, fish & eels). On the current evidence, snorkelling provides the most sensitive and rapid visual technique for detecting rainforest stream fauna. However, in stream sections dangerous to human observers (e.g. inhabited by crocodiles, entanglement, extreme flows), we suggest the stratified deployment of multiple BRUVSs across a range of stream microhabitats within each site.