Thinking about the creatures living in the coral reefs located under the deep ocean, your attention might be drawn to the giant oyster, which can be up to a meter in length and weigh up to 250 kg, it is the largest aquatic oyster on earth. But despite its size and fame, the giant oyster is in peril. The tropical waters of the Indo-Pacific are warming due to climate change, and their shells and meat are in great demand. For these reasons some are already locally extinct.
Our new research out today finds that these iconic giant water creatures are facing new threats such as ocean warming and the acidic oceans that come with climate change. Is their game over? Not now. We believe there are new ways we can manage shellfish on coral reefs, as well as new breeding programs designed to address these threats and when we reach net-zero greenhouse gas emissions. If so, then you get time to save them.
Charismatic creature The only invertebrate of the eight great species
Despite being called man-eaters in 19th-century tales of exaggerated sea voyages and Pacific island legends—giant oysters are great creatures. These charismatic creatures are the only invertebrates out of eight great species to be included in the list of things to see for Great Barrier Reef visitors, along with manta rays and clownfish. Here, the giant oyster is adequately preserved and visitors can see eight of the world’s twelve giant oyster species.
Giant oysters are still plentiful in Australian waters, with their numbers decreasing in other areas due to over-exploitation. We need other ways to protect our giant oysters from new threats to come. If we save them, we can also save other creatures living in coral reefs by their fame. This will save coral, fish and other invertebrates. Nine giant oyster species have long been included in the Red List of Species due to overexploitation by the International Union for Conservation of Nature.
Climate change and pollution pose major threats to giant oysters
All giant oysters are protected under the Convention on International Trade in Endangered Species of Wild Fauna and Plant Appendices. Rapid global climate change and pollution now pose major new threats to giant oysters, while slowly acidifying oceans now affect all giant oyster species from the Red Sea to the Pacific Ocean. Ocean acidification makes it difficult for animals to build and maintain a strong shell, especially during their early life. The best biodiversity conservation strategy is to reach net-zero carbon dioxide emissions as soon as possible and achieve a stable climate by limiting global warming to a limit of 1.5 °C. This will help save giant oysters and coral reefs.
Soo-Ann Watson, James Cook University and Mei Lin Neo, National University of Singapore