First record of biological traits of the Australian endemic longfin pike (Dinolestes lewini : Dinolestidae)

Abstract

Dinolestes lewini (longfin pike) is a common, but little studied, fish species endemic to temperate marine-dominated waters below ~31°S on the east, south and west coasts of the Australian mainland and around Tasmania. Samples of longfin pike collected in Lake Macquarie, a large coastal lagoon in south-eastern Australia, were examined for age, growth and reproductive characteristics. Spawning occurred over an extended period between at least October and March (austral spring to autumn), and although spent individuals occurred in samples, spawning location could not be ascertained. Examination of otolith edge condition provided strong support that opaque and translucent zones were deposited annually and that counts of opaque zones on otoliths can be used to estimate ages. Sex-related differences in mean length at age and projected growth based on the von Bertalanffy growth function were evident. Growth trajectories diverged at ~1.5 years of age, after which females grew faster than males for a longer period, eventually attaining greater observed maximum lengths and ages. Observed longevity was 5+ and 9+ years for males and females, respectively. The data provide an initial knowledge-platform for incorporation in species assessments and for further comparative investigations of variation in biological traits across the species’ distribution.