What is Blue Coral?

Blue coral is a type of stony coral commonly found in tropical reef flats or slopes in the southern hemisphere of the pacific ocean. This coral gets its name from the blue color of its skeleton, which also makes it highly desirable in the tourist trade. The scientific name for blue coral is Heliopora coerulea.

Although coral often looks more plant-like, it is actually an animal. The hard bony structures people commonly associate with coral is actually the skeleton which is secreted by the polyps, the moving parts of the coral. Each polyp's skeleton is joined to others, creating a colony. Like most stony corals, in blue coral, the polyps are small. Each polyp has a truck on one end, which is attached to the colony, and eight tentacles around its mouth opening on the other end.

Blue coral is found near the coast of Australia, Japan, and Indonesia, as well as parts of Africa and India. It is also, rarely, found around Fiji. It usually lives in shallow waters, less than 6.6 feet (2 m) deep. Colonies vary in size, but some may reach over 6 miles (10 km) across. When viewed along with the surrounding environment, a colony is usually called a coral reef, which provides a habitat to a wide variety of animals and plants.

Like most coral, blue coral is a hermatypic coral. Hermatypic corals live in symbiosis with algae called zooxanthellae, which inhabit the coral's tissue, enjoying the protection of the colony. Although the coral is not capable of photosynthesis, the algae are, and the nutrients produced are shared between the algae and the coral.

Blue coral reproduces sexually. Called brooding, a polyp will grow one or two larvae inside eggs within its body. Once hatched and outside the polyp, the larvae will attach to the colony. Larvae cannot swim, so any movement away from the parent polyp is due to ocean currents.

Although blue coral is often considered common in the areas it is found, like most coral, it is threatened by the pollution and overfishing which often causes the destruction of delicate reef environments. In addition, this coral is also harvested for trade. Made into jewelry or used in aquariums, blue coral was harvested extensively in the late 1980s throughout most of the 1990s. Now may colonies are found in protected areas of the ocean, which limits the destruction of their environments, but many are still harvested for trade.

Blue coral, scientifically known as Heliopora coerulea, is a unique species of coral distinguished by its striking blue skeleton. It's the only extant species in the family Helioporidae and is found in the Indo-Pacific region. Unlike most corals, which have calcium carbonate skeletons, blue coral's skeleton is composed of a fibrous, crystalline form of calcium carbonate called aragonite, which gives it the characteristic blue color.

Blue coral is typically found in the shallow waters of the Indo-Pacific, from the East African coast to the central Pacific Ocean. It thrives in areas with moderate wave action, often forming extensive colonies on reef slopes and flats. These corals prefer depths ranging from 2 to 60 meters, where sunlight can still penetrate to aid their symbiotic algae, zooxanthellae, in photosynthesis.

According to the International Union for Conservation of Nature (IUCN), blue coral is listed as a Near Threatened species. This status is due to its susceptibility to bleaching, disease, and damage from destructive fishing practices and coral mining. Conservation efforts are crucial to prevent its further decline and to maintain the biodiversity of reef ecosystems where it plays a role.

Blue coral stands out from other corals primarily due to its unique blue-colored skeleton. Additionally, it is a hermatypic, or reef-building, coral with a fibrous skeleton rather than the typical stony structure of most reef-building corals. It also has a smooth, non-porous surface and can grow in both branching and plate-like forms, contributing to its distinctiveness.

Blue coral contributes significantly to marine ecosystems by providing habitat and shelter for a diverse range of marine life, including fish, invertebrates, and other coral species. Its structure helps protect coastlines from erosion and wave damage. Moreover, as a reef-building coral, it plays a vital role in the formation and maintenance of coral reefs, which are among the most biodiverse ecosystems on the planet.

Blue coral has been used in jewelry and decorative objects due to its unique color and texture. However, due to its Near Threatened status, the use of blue coral for such purposes is not considered sustainable. Ethical considerations and regulations often discourage the harvest of blue coral for commercial use to protect the species and preserve marine biodiversity.