SPAWNING OF THE BROAD-FINNED GALAXIAS, GALAXIAS-BREVIPINNIS GUNTHER (PISCES, GALAXIIDAE) IN COASTAL STREAMS OF SOUTHEASTERN AUSTRALIA

The broad-finned galaxias, Galaxias brevipinnis, spawned during high f lows in mid autumn. Spawning took place over inundated riparian areas where eggs were laid amongst substrate, mainly in the interstices of c obbles and pebbles. Between subsequent high flows, eggs were out of wa ter for days or weeks, lying up to 7 m from the water's edge. When exp osed, eggs and streamside substrate remained damp, shaded by surroundi ng forest. Hatching would only occur when eggs were inundated by a sub sequent flood. In the held, most eggs had hatched within 30 days of th e spawning period, but some remained unhatched for up to 60 days. In t he laboratory, eggs remained unhatched for up to 57 days under moist c onditions but out of water, and up to 120 days when kept in water. How ever those kept under drier conditions died. It would appear that ripa rian cover may be important in providing shaded and moist conditions f or the survival of eggs in the wild. Evidence of some adult mortality following spawning was noted. Newly hatched larvae were carried to sea during high hows. Predation on eggs by both adult G. brevipinnis and introduced brown trout Salmo trutta Linnaeus was found to occur.