Thus, this alga has been found to jump from the coast of one port city to the coast of another port city. The natural strain has both male and female individuals and additionally reproduces sexually. Gametes are expelled from each sex and meet to form a zygote which then goes through two larval stages before becoming an adult. In 2000, the strain was found on the coast of California (U.S.), near San Diego, and also on the coast of New South Wales, Australia. The California colonization was small enough to be considered controllable: it was covered with tarpaulin which was held down with sandbags at the edges of the infestation. Then chlorine was poured in through tubes which fed into certain openings in the tarpaulin: the interior of the tarpaulin filled up with chlorine and killed living organisms inside it, not only the unwanted alga but also fish, invertebrates and other seaweeds. The killing of such other organisms was not desirable but was deemed preferable to letting the algae grow unchecked. The appearance off the California coast was most probably caused by an aquarium owner improperly dumping the contents, allowing "C. taxifolia" to flow through a storm sewer into the lagoon where the invasion was discovered. California has since passed a law forbidding the possession, sale or transport of "Caulerpa taxifolia" within the state. There is also a federal law under the Noxious Weed Act forbidding interstate sale and transport of the aquarium strain "Caulerpa". In July 2006, the alga had been declared eradicated from the two Southern California locations (Agua Hedionda Lagoon in Carlsbad and Seagate Lagoon in Huntington Beach). Researchers at the University of Nice in France have been studying a tiny aquatic slug which is a natural predator of "C. taxifolia". Called "Elysia subornata", it was found off the coast of Florida, in waters warmer than those in the Mediterranean. This slug is believed to feed exclusively on "C. taxifolia", by sticking its proboscis into the stem and sucking out the white viscous liquid inside the stem: this causes the alga to become limp, discolored, and dead. As the slug does so, it absorbs the alga's poison. The slug has an enzyme which neutralizes the noxious effect of the poison, and at the same time, the poison protects the slug from being eaten by fish. However, this slug cannot survive in the cooler waters of the Mediterranean and, therefore, is unable to control the invasive alga there.