Cabbage Tree Bay Aquatic Reserve is one of few fully protected marine areas around Sydney. Despite its small size, an incredible diversity and density of life has flourished since its introduction 23 years ago. Local and international swimmers, snorkellers and divers enjoy it. A shining light for marine conservation and ecotourism. Occasionally when conditions are right jelly blubber (Catostylus mosaicus ) numbers explode. On this occasion a smack of many thousands was present providing food for some of the other inhabitants.