Viviparity and the reproductive ecology of clinid fishes (Clinidae) from temperate Australian waters

Abstract

Viviparity is reported in twelve species of the family Clinidae in Tasmanian waters, and superfoetation (the simultaneous development of multiple batches of eggs and/or embryos) in nine of the twelve (all in the subfamily Clinini). The reproductive anatomy and life history features are documented in two superfoetate, shallow-water species,Heteroclinus perspicillatus andHeteroclinus sp. nov. (Scott's Weedfish). Gestation of embryos is intrafollicular and their mode of nutrition shifts from lecithotrophy during early development to trophodermal matrotrophy and, eventually, intestinal nutrient transfer. The sizes of the newly born larvae differ between species, but in all cases maternal investment in individual offspring (as measured by the proportionate increase in embryo dry weight)—20125%, 5744% and 3140% forH. perspicillatus, Scott's Weedfish andH. heptaeolus, respectively — is among the highest recorded for teleosts. Relative fecundity, however, is comparable to those of temperate, demersal spawning blennioids, and this suggests that high levels of maternal investment and relatively advanced stages of larval development at parturition for the sub-family as a whole do not involve a cost in individual fecundity. Parturition, which occurs over several months in spring and summer, is asynchronous. After parturition, the larva spend from 3 to 7 weeks in the plankton, primarily in in-shore waters. Post-settlement growth is rapid and most of the reproductive populations consist of fishes in the 1 + year-class.