Rivers of northern Australia contain a high diversity of freshwater fishes, which are ecologically, socially and culturally important. Little information is currently known on their basic early life history requirements, particularly spawning times, nursery habitat and survival requirements of young. In addition, there are a variety of anthropogenic changes (e.g. water extraction, river regulation, land use change, population expansion and climate change) posing imminent threats. At this critical time, we investigated the spatial and temporal variability of freshwater fish spawning during the dry season low flow period in the Daly River, and what specific nursery habitats are being used for breeding during this period.

Sampling of fish early life stages occurred at 6 weekly intervals (May-October), in three river reaches of the Daly River. A suite of standardised methods was trialled, with Sweep Net Electrofishing and light traps being most effective, and drift and trawl nets yielding very small numbers. Spawning occurred throughout the dry season, with peak abundance occurring for some species towards the end of the dry season, leading into the resource rich wet season. A total of 14 species were collected as larvae and 24 as juveniles. Strong diel variation was also evident, with higher larval abundances at night.  The majority of larval and juvenile fish were collected in littoral habitats (of varying characteristics) and not collected in the main channel. 

This study forms part of a larger on-going project that will contribute towards an understanding of spawning and recruitment requirements of fishes in the Daly River.