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

Abstract

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˚C and 15˚C, and gametophytes and immature sporophytes developed between 10˚C and 20˚C.