Occurrence of Undaria pinnatifida (Phaeophyta: Laminariales) in Port Phillip Bay, Victoria, Australia

In July (winter) of 1996 Undaria pinnatifida f. typica (Harvey) Suringar was found growing on basalt reef and rock/shell rubble in 2-4 m of water near Point Wilson, Port Phillip Bay, Victoria. The population grew prolifically over winter-spring with a density of up to 140 plants m(-2), with sporophytes attaining a maximum length of approximately 800 mm. Size-frequency distributions of the population in September 1996 suggested that the population was actively recruiting, and examination of sporophylls indicated that plants reached reproductive maturity at a length of approximately 400 mm. Release of zoospores was achieved in the laboratory at temperatures between 10 degrees C and 15 degrees C, and gametophytes and immature sporophytes developed between 10 degrees C and 20 degrees C.