In the Mediterranean Sea, the molluscs Oxynoe olivacea and Lobiger serradifalci are found on C. taxifolia and feed on it. The grazing rate of these two ascoglossans is low and significantly effected by temperature. Elysia subornata is an opisthobranch that feeds only on species of Caulerpa and is a potential for biological control of C. taxifolia in the Mediterranean. During summer and autumn, the toxic substance produced by C. taxifolia, caulerpenyne, may be the reason there are few consumers (NIMPIS, 2002).
Research on the Mediterranean and tropical strains of C. Taxifolia revealed some major differences between them. The Mediterranean strain has larger fronds, lacks female gametes, can withstand lower temperatures, and has increased concentrations of defensive chemical metabolites (Raffaelli et. Al, 1997).
C. Taxifolia appears to have been distributed around the Mediterranean as fragments attached to ship anchors, as the locations of new outbreaks are predominantly associated with port and mooring facilities (Meinesz et. Al, 2001b).
Observation of native populations of C. Taxifolia growing at temperatures of 9 to 11°C in Moreton Bay, Australia, has raised doubts over whether the Mediterranean populations are of a genetically-modified, cold-adapted strain, as has been asserted by some authors (Phillips & Price, 2002).
The temperature range for the Mediterranean strain is 7°C - 32.5°C, while the maximum salinity is 38 ppt (NIMPIS, 2002).
Principal source: National Introduced Marine Pest Information System (NIMPIS). 2002. CSIRO, Australia.
Compiler: Dra. M� Antonia Ribera, Laboratory of Botany, Faculty of Pharmacy, University of Barcelona, Spain & IUCN/SSC Invasive Species Specialist Group (ISSG)
Review: Dra. M� Antonia Ribera, Laboratory of Botany, Faculty of Pharmacy, University of Barcelona, Spain.
Publication date: 2006-04-18
Recommended citation: Global Invasive Species Database (2024) Species profile: Caulerpa taxifolia. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=115 on 02-11-2024.
C. Taxifolia outcompetes the seagrasses Posidonia oceanica and Cymodocea nodosa in Mediterranean ecosystems (NIMPIS, 2002).
Economic impacts resulting from the cost of eradication included approx $US6 million spent in Southern California up to 2004 (Anderson, 2004) and $AUS6-8 million in South Australia.
Chemical: Colonies of C. taxifolia that were discovered in Southern California were eradicated by covering and sealing them with PVC tarpaulins and injecting liquid chlorine underneath. Subsequent treatments at another location used solid chlorine formulations (Anderson & Keppner, 2001). Costs of the Southern Californian eradication were $US2.33 million from 2000-01 for control and monitoring (Carlton, 2001), with an ongoing annual surveillance cost of $US1.2 million until 2004 (Anderson, 2004).
Application of coarse sea salt at a concentration of ~50kg/m² has been used with moderate success in Australia, eradicating C. taxifolia from an area almost 5200 m² in one case, although in another case an area of 3000 m² showed a reduction in algal density but eradication was not achieved. The use of this method in the cooler months, when C. taxifolia naturally dies back, was recommended. Salting has so far only been succesfully used on soft sediments in water <6m in depth (Glasby et. Al, 2004).
Physical: Simply covering C. Taxifolia colonies with black PVC plastic was found to be reasonably successful in Croatia. A total area of 512 m² was treated, with either no or sporadic regrowth occurring after treatment (McEnnulty et. Al, 2001).
Manual removal by scuba divers was successful in eradicating a small patch of C. Taxifolia, around 3.4 m², in the French Mediterranean. The use of a suction pump to remove all fragments has also met with moderate success in other areas. Clearance rates for manual removal are from <1 m² to ~3 m² per diver per hour (McEnnulty et.al, 2001).