Age‐related growth characteristics of Galaxias fasciatus (Salmoniformes: Galaxiidae)

Galaxias fasciatus Gray is one of the diadromous galaxiids whose juveniles are known in New Zealand as whitebait. Its otoliths are shown to have a regular pattern of summer and winter zones that can be used for age determination. Age and annual growth were examined in specimens from the South Island and from the Owhiro Stream, Wellington. A form of the von Bertalanffy growth equation was used to fit curves to the observed data. Body lengths ranged from 4 cm in juveniles just entering fresh water to nearly 25 cm in the largest adults. Females were found to grow faster and to reach a greater size than males. The oldest fish successfully aged was in its tenth year. About 21% of fish from Banks Peninsula exceeded age 5, but only 7% from Owhiro Stream were older than this.