Apra Harbour (51) which is under serious threat from development for a power plant and generating and industrial facilities. Pavona frondifera is already being affected by heated water discharges and it is feared that the other species could be similarly vulnerable W. 2, Disturbance Reefs near tourist resorts and industrial and urban developments are particularly vulnerable. Corals are easily damaged by boats and anchors (39f7), trampling, and fishing with explosives and chemicals such as chlorine W). In a few cases habitat destruction could have a serious effect on a coral species, since some stony corals appear to have limited ranges. For example, Oculina robusta O. tenella Labellum fragile and Caryophyllia horologium are endemic to Florida 09) and in Guam three species ( Euphyllia~ sp, Plerogyra sinuosa and Tubastrea aurea ) are thought to be vulnerable on account of their rarity (20,51). 3. Exploitation The collection of stony corals for building and industrial purposes has caused the loss of large tracts of reef in countries such as the Philippines (25), Sri Lanka (56), Malaysia (57) and Indonesia (58). The ornamental coral trade has also had localized impacts in several countries, including the Philippines (59,60) and Hawaii (23). The main problem seems to be that small immature colonies are preferred and there is intensive localization of collecting in certain areas. Colonies of Seriatopora for example, have virtually disappeared from some areas in the Philippines (25). On Hawaiian reefs collection of coral colonies by tourists had a local impact in the 1970s. Fungia scutaria one of the rarer corals found principally in Kaneohe Bay in Oahu, declined as a result of the combined effects of over-collection and pollution. Its limited distribution and low abundance made it particularly vulnerable (23, 2). CONSERVATION For many cnidarians, few data are available to assess the effects of human activities although for corals there is evidence that action must be taken rapidly to preserve a resource of great ecological and economic importance. Although there is little danger of any coral species becoming extinct it is clear that many coral reefs are seriously threatened. Fortunately, steps are already being taken to control some of man's more damaging activities. The Reefwatch project, run from the Tropical Marine Research Unit at York, U.K, is assembling data on the current condition of reefs worldwide using amateur and professional divers. Handbooks have been and are being produced by LUCN, the South Pacific Commission and UNESCO to provide guidelines for monitoring and managing coral reef ecosystems (15,41). Coral reef reserves have been established in many countries and survey work is being carried out to locate further potential sites. Consideration is being given to the type of reserve implemented, so that local people may still exploit and benefit from the resources of the reef. The Great Barrier Reef Marine Park is one example. The Australian government has established a management regime which provides for multiple use of the reef while ensuring that the important qualities of the ecosystem are protected (50). Numerous examples of parks and reserves for coral reefs could be cited, and methods of establishing and managing these were discussed in detail at the Third World National Parks Congress in 1982. However, the proliferation of such reserves is not a reason for complacency, as methods for maintaining these areas, and conflict with fishermen and other users, still present considerable problems. In temperate countries little interest has been shown in cnidarians, although reserves may be required to protect species with limited distributions or restricted to vulnerable habitats such as estuaries and salt marshes. Exploitation and trade in corals and other cnidarians should be managed. In several countries eg. U.S.A. (Florida) (19), Bermuda (64), Bahamas (63) and Guam (20), the taking of corals, sea fans and other cnidarians is prohibited or restricted. Fishery management plans are being drawn up for coral resources in the Gulf of Mexico (30), and for precious coral in the western Pacific (see reviews). Corals 25