Ecology and Management of the Invasive Marine Macroalga Caulerpa taxifolia

Abstract

In coastal waters of Australia, the USA, and Europe, aquarium strains of the green macroalga Caulerpa taxifolia have invaded and caused ecological and economic disasters. As a result, this alga was placed on the International Union for the Conservation of Nature’s list of 100 worst invasive species. Two things have promoted the invasions. First, C. taxifolia asexually reproduces by vegetative fragmentation. Fragments as small as 4 mm can survive and attach within 2 days. Second, this species has been and continues to be very popular with the aquarium industry, prized by both home hobbyists and public aquaria. Although regulations are now in place in many countries, retail shops and e-commerce continue to sell many species of feather Caulerpa, including C. taxifolia. “Aquarium dumping” is thought to be the reason for most, if not all, of the major invasions. Field eradication efforts have included manual and vacuum pump harvesting, covering colonies with opaque tarpaulins, subjecting C. taxifolia to a range of noxious chemicals, temperature, and salinity shocks, while outreach, monitoring, and modeling are promoted as ways to prevent future incursions. To date, only the USA and the West Lakes area of South Australia have eradicated C. taxifolia. Further research and outreach are needed to prevent future invasions of this noxious alga.