The biology of a landlocked form of the normally catadromous salmoniform fish Galaxias maculatus (Jenyns). I. Life cycle and origin

摘要: In contrast to most other members of the family Galaxiidae which live and reproduce in fresh water, Galaxias maculatus, common jollytail Australia "whitebait" New Zealand, is normaIly catadromous throughout its range (south-eastern Australia, southern South America). some athalassic inland lakes on volcanic plains south-western Victoria, however, a number populations apparently descended from this species have becomelandlocked. The life cycle forminhabiting one these (the "landlocked jollytail" Lake Modewarre) may be briefly summarized as follows: Gonadal maturation adult fish, slightly saline landlocked lake, begins around March almost completed by about June. final stage not reached, until fish migrate short distances up intermittent inflowing creeks when latter begin flow late winter spring (July-October). Spawning takes place are swollen after heavy rain, eggs being deposited amongst flooded vegetation shallow areas slow-flowing water along creek banks. Many spent die spawning. eggs, stranded flood-waters subside, develop banks above normal level. After development complete reimmersion first flood cover them stimulates hatching. developmental period probably 2 weeks, but absence flooding hatching can delayed at least month fertilization. newly hatched larvae washed downstream into lake where they feed grow maturity. They upstream spawn following winter-early season an age approximately 1 year. 9 cm their year, 14 second, 17 third average size females greater than that males. general features history form compared contrasted with those stream-dwelling G. maculatus salmoniform fishes. geological origin complex Victoria inhabited galaxiid discussed, hypothesis concerning Modewarre ancestral population Barwon-Leigh River system advanced.