First observations on the timing and location of giant kokopu (Galaxias argenteus) spawning

The giant kkopu, Galaxias argenteus (Gmelin, 1789), is the largest of the galaxiid species and is endemic to New Zealand. While it was the first of the galaxiid species to be described, knowledge of its ecology remains relatively poor, particularly with respect to the reproductive phase of its life-cycle. This article describes the first observations of giant kkopu spawning sites in the natural environment. A total of nine spawning sites have been discovered across two spawning seasons in an urban stream in Hamilton, New Zealand. Giant kkopu are confirmed to follow a similar spawning strategy to the other whitebait species. Eggs are deposited in riparian habitats while temporarily submerged by elevated water levels. Eggs then develop terrestrially before hatching when the egg deposition sites are re-inundated during later high flows. This spawning strategy leaves giant kkopu highly susceptible to flow regime and riparian alterations.