Until about the last decade, the freshwater fish fauna of Stewart Island had seldom been
studied No comprehensive attention had been given to determining the species present there
or their distributions, and the number of freshwater fish site records from the island, derived
largely from localised or short-term/ad hoc collections, was small However, Chadderton
(1988) listed six species based on collections around the northern half of Stewart Island that
included quite intensive sampling of the Rakeahua River catchment, and later (Chadderton
1990) reported 12 species following sampling more widely from catchments of eastern and
coastal rivers All of these recorded species are diadromous (sea-migratory at some life
stage—McDowall 1988), except fish that Chadderton (1990) recorded as Galaxias vulgaris
Stokell from the Rakeahua River and Duck Creek in central Stewart Island and the Robertson
River in the far south (Fig 1) Identifications of these populations have, however, proved
erroneous (see below)