Biology Reference
In-Depth Information
pumps in Croatian waters. Eradication with suction pumps was tested in four locations
in 1996 and 1997 after
C. taxifolia
invaded Croatia in 1994. There was extensive
regrowth in three of the four locations. To be effective, Zuljevic and Meinesz (2002)
noted that suction pumping needed to be repeated after short while and eradication
was more effective if the patch was small. Initial eradication attempts in NSW,
Australia also included physical removal by hand and suction pump (Glasby et al.
2005a). Again, hand removal was abandoned because of the intense labor involved
(<1-3 m
2
per diver per hour) and fragmentation caused by the removal process
(Glasby et al. 2005a). In only one place is hand removal continuing. At the French
National Park of Port Cros, annual hand removal plus applying cloths soaked in cop-
per salts has occurred since 1994 to remain local biodiversity for SCUBA divers
(Rierra et al. 1994; Thibaut 2001; Madl and Yip 2005).
15.5.2 Smothering Colonies
Black tarpaulins (20-30-mil PVC), surrounded by PVC frames and weighted down by
gravel-filled bags, were used in the successful eradication campaign in California
(Anderson 2005). Chlorine was injected into the confined space under all tarps, so it
was not possible to determine if both treatments were required for
C. taxifolia
eradica-
tion. In other locations, tarps to smother individuals or inhibit photosynthesis were not
successful. Zuljevic and Meinesz (2002) tested 0.15-mm thick black plastic tarps that
were 4-m wide and suggested that this technique would be useful for all types of sub-
strata. However, success was limited because of damage to tarps from anchoring, fish-
ing, and storm events (Zuljevic and Meinesz 2002). In NSW, heavy rubber conveyor
belts and jute matting (hessian) were tested and soon abandoned because the method
was excessively labor intensive, tears in the tarps allowed for survival of some
C. taxi-
folia
, and high mortality of many species in the impacted area (Glasby et al. 2005a).
15.5.3
Changes to Local Salinity
Caulerpa taxifolia
was found in West Lakes and the upper reaches of the Port River
in South Australia in 2002 (Cheshire et al. 2002; Westphalen and Rowling 2005),
prompting a significant eradication program. The West Lakes system is an artificial
marine water body constructed in the 1970s and filled from Gulf St. Vincent at the
south end by the tide. With an average salinity of 35 ppt, the system extends 7 km
from north to south, is less than 500-m wide, and ranges in depth from 3 to 7 m
(Collings et al. 2004). After extensive literature review, understanding the local flow
regime, and mesocosm salinity trials, managers closed West Lakes to the sea and
replaced the saltwater with freshwater. Freshwater was pumped from the nearby
Torrens River. Any negative impacts were deemed acceptable by managers because the
river historically drained through the area that included West Lakes and infrastructure
