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water flow system. In August 1992, the aquarium staff observed two colonies of
C. taxifolia (0.2 and 1.0 m diameter) in a coarse sand bed about 5 m from the pool's
discharge pipe in the Sea of Japan (Komatsu et al. 2003). Both colonies disappeared
in the winter of 1993. Two new colonies were observed in 1994; both disappeared
in the winter (Komatsu et al. 2003). After that, the Notojima Aquarium began keeping
their C. taxifolia cultures in a closed system. This Japanese aquarium strain geneti-
cally was identical to the Mediterranean aquarium strain (Komatsu et al. 2003).
C. taxifolia did not become established in Japanese waters most likely because the
water temperatures in the winter dropped below C. taxifolia's lower lethal limit
(Komatsu et al. 2003). No C. taxifolia has been documented in Japanese waters
since that time.
Populations of C. taxifolia were next discovered in April 2000 in Fisherman's
Bay, Port Hacking along the southern outskirts of Sydney, Australia, more than
800km south of its closest native distribution in the state of Queensland, where
observational records date back to 1860 (Schaffelke et al. 2002). Also in April
2000, C. taxifolia was documented 200km south of Sydney in Lake Conjola
(Fig. 15.2). Researchers predict that the Port Hacking infestation started 2 years
prior and the Lake Conjola infestation began 5-13 years earlier (Creese et al. 2004).
In Australia, the number of invaded locations continues to increase with ten docu-
mented coastal lakes/estuary infestations in New South Wales (NSW), both north
and south of Sydney, and two waterways in South Australia (Schaffelke et al. 2002;
Millar 2004). Presently, Lake Conjola has the distinction of being the most severely
infested location in NSW, and possibly Australia (West and West 2007). Here,
Caulerpa taxifolia has replaced seagrass as the dominant macrophtye, covering
approximately 30% of the lake floor (Creese et al. 2004). All invaded locations in
Australia are relatively sheltered areas, are less than 10-m deep, and are soft sedi-
ment habitats that were either previously uncolonized or occupied by seagrasses
(Creese et al. 2004; Davis et al. 2005).
Schaffelke et al. (2002) and Murphy and Schaffelke (2003) used molecular
markers and determined that invasive C. taxifolia in Australia was not identical to
the aquarium strain. Nor were NSW populations the result of a natural, southward
range expansion along the eastern coastline (Phillips and Price 2002; Millar 2002).
Most likely, the new infestations were the result of multiple domestic translocation(s),
aided by boating, fishing, and the domestic aquarium trade (Schaffelke et al. 2002,
2006). Some areas, such as Port Hacking, have aquarium shops near shorelines,
which stocked and sold C. taxifolia at the time the infestations were thought to have
occurred (Creese et al. 2004). Other infested areas were much more remote, sug-
gesting that boating and fishing activities were important for the transport of frag-
ments (Relini et al. 2000). Indeed, many remote NSW infestations were popular
fishing spots (Creese et al. 2004). Additionally, some areas where C. taxifolia cur-
rently is found were important commercial grounds prior to the lakes being closed
to commercial fish netting in May 2002.
The year 2000 was a critical year for recognition of global infestations of
C. taxifolia . In addition to the Australian invasions, populations of the aquarium
strain of C. taxifolia were found in two lagoons in southern California: Agua
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