Reef Fish in Peril:
Protecting Clownfish and Damselfish
The orange clownfish — famous for its leading role in the movie Finding Nemo — and an array of brightly colored damselfish are part of a family of fish (known as the “pomacentrids”) that depend on coral reefs. Global warming is putting them at risk of extinction, so the Center for Biological Diversity filed a petition on September 13, 2012, to protect the orange clownfish and seven of the most vulnerable damselfish in U.S. waters under the Endangered Species Act. About a year later, we filed a notice of intent to sue the National Marine Fisheries Service for the agency’s failure to act on our petition.
Orange clownfish protect themselves from predators by living amid the tentacles of sea anemones that grow on coral reefs. Similarly, the seven damselfish in our petition take shelter directly among the corals, which some species also rely on for food. But greenhouse gas pollution hits reef-fish habitat with a double whammy that has caused nearly every reef in the world to suffer declines. First, global warming is heating up the oceans, which increases the frequency and intensity of mass bleaching events that can kill corals. Second, as the main greenhouse gas — carbon dioxide — increases in the atmosphere, more and more CO2 is absorbed by ocean water, where it spurs chemical reactions that make the water more acidic. Ocean acidification reduces the ability of coral reefs to grow.
Scientific studies are now showing that the conditions created by increasing greenhouse gas pollution will also harm clownfish and damselfish directly. Rising water temperatures can interfere with fish reproduction and reduce their swimming capabilities. At the same time, ocean acidification damages fish nervous systems, impairing their ability to see, hear and smell. These effects are particularly devastating to young fish that start their lives in the open ocean and then must locate coral reefs in which to make their homes. To add insult to injury, while ocean acidification is disrupting the senses clownfish and damselfish use to find homes and avoid predators, its effects can also confuse these fish so much that they are actually attracted to the odors from predators, according to recent studies. As a result, at CO2 levels expected later this century, some damselfish species could suffer predation rates five to nine times higher.
Beyond all of the dangers from greenhouse gas pollution, the orange clownfish and some damselfish may also face threats from the global marine aquarium trade. Clownfish and damselfish are by far the most commonly traded species worldwide, accounting for more than 40 percent of all fish traded. Some studies suggest that the orange clownfish and black-axil chromis may be suffering declines in the wild due to over-harvesting for aquariums.
Urgent action is needed to save these remarkable fish from extinction. Along with our petition to protect the orange clownfish and seven species of damselfish living in U.S. waters — blue-eye damselfish, Hawaiian dascyllus, yellowtail damselfish, black-axil chromis, Dick’s damselfish, reticulate damselfish and blue-green damselfish — under the Endangered Species Act, we’ve also filed petitions to protect the corals they need to survive. The Endangered Species Act provides a suite of conservation tools that would create a safety net for reef fish and corals, as well as tools to help address the threat from greenhouse gas pollution.