Emergence of field-based underwater video for understanding the ecology of freshwater fishes and crustaceans in Australia

Underwater video is increasingly being used to record and research aquatic fauna in their natural environment, and is emerging alongside Dual Frequency Identification Sonar (DIDSON) as a powerful tool in Australian freshwater ecology. We review current progress with field-based applications of underwater video in studying Australian freshwater fish and crustacean ecology. Drawing upon searches of online literature databases and our expert knowledge, we located 11 relevant publications: five set in the Murray-Darling Basin, three in the Eastern Province, two in the Northern Province and a single study in the Pilbara Province. In total, 10 studies reported using video for fish ecology, while three studies included crustaceans. Across the 11 publications, eight examined threatened species, while the remaining studies developed video techniques for surveying species richness in remote or difficult to access habitats. Habitat-use was also a dominant theme (seven studies). Seven of the eight studies that centred on threatened species focused on at least one percichthyid species in either the Murray-Darling Basin or the Eastern Province. Miniaturisation in equipment and increases in compact battery capacity seem to have driven a shift from above-water battery supplies and data storage to small, inexpensive and mobile underwater cameras. We foresee wider use of video in freshwater ecology primarily in the study of animal behaviour and also to improve species detection in field surveys. There is scope for testing novel techniques such as animal-borne video and unmanned underwater vehicles and making use of video in citizen science initiatives.