ABSTRACT
Ssp. tomentosoides next appeared on NW Atlantic shores in 1957, NE Pacific shores in 1977, New Zealand shores in 1973, and Australian shores about 1995 (Bouck & Morgan 1957, Dromgoole 1975, Silva 1979, Carlton & Scanlon 1985, Trowbridge 1995, C.Hewitt, CSIRO, pers. comm.). The alga’s appearance was noticed in most of these cases because the areas invaded lacked native conspecifics. For example, there are no native species of Codium in the NW Atlantic north of Cape Hatteras (Silva 1962), and there are no native subspecies of C. fragile in Auckland Harbour, New Zealand (Dellow 1952, 1953, Dromgoole 1975, 1979, Trowbridge 1995) or San Francisco Bay, USA (Silva 1979). In Australia, however, the alga invaded Port Phillip Bay and environs (C.Hewitt, pers. comm.). According to Silva & Womersley (1956), there are two native subspecies (tasmanicum and novae-zelandiae) not only in the region, but also in and around Port Phillip Bay itself, rendering this invasion extremely difficult to detect.
