The Australian spotted jellyfish (Phyllorhiza punctata) is a species of jellyfish native to the western Pacific from Australia to Japan but has been introduced widely elsewhere. It feeds primarily on zooplankton. The Australian spotted jellyfish generally can reach up to 50 centimeters in bell diameter, but one 72 cm wide jellyfish was spotted on Sunset Beach, North Carolina.
The species has been found in the waters off the Hawaiian Islands since at least 1945, in the Mediterranean Sea since at least 1965, and in large numbers in the Gulf of Mexico since 2000. In the eastern Pacific, it has been sighted in the San Diego area and the Gulf of California as early as 1981. While it is not known how it was introduced to these regions, it has been theorized that budding polyps may have attached themselves to ships, or were carried in a ship’s ballast tank which was subsequently dumped. As an invasive species, it has become a threat to several species of shrimp. In Gulf waters, the medusae grow to unusually large size, upwards of 60 cm across.
Their ability to consume plankton and the eggs and larvae of important fish species is cause for concern. Each jellyfish can filter as much as 50,000 of seawater per day. While doing that, it ingests the plankton that native species need. In North America and Hawaii, its non-native locations are the Northern Gulf of Mexico, Southern California, Greater Antilles, Florida, and the Hawaiian Islands. They are also threatening large fishing industries because of their consumption of eggs and the larvae of fish, crab and shrimp.