Many cultured pearl farms are located in areas of the Pacific that boast the greatest marine biodiversity on the planet. These are also areas that are affected by coral reef degradation. Coral reefs play an important role in the life cycle of pearl oysters: they are substrates for reproduction, sources of nutrients for oysters and home to many fish and other organisms that play an important role in maintaining oyster health. In French Polynesia, for example, many smaller farms let reef fish remove biofouling from pearl oysters. This practice is founded on healthy fish populations that are often found in reef ecosystems.