In marine and coastal areas, the main threat to biodiversity arises from the over-exploitation of marine and coastal resources and from related fishing practices, although pollution and coastal degradation also represent significant threats.
Habitat conversion and degradation, overexploitation, pollution and sedimentation, coastal erosion, eutrophication, species introductions and climate change are considered the major causes of marine biodiversity loss.
Between 1970 and 2002 the ocean's biodiversity reduced by a third.
Many marine fisheries have been grossly over-exploited, and their recovery will be slow. Future growth in demand for fish will have to be satisfied by aquaculture - itself a practice fraught with environmental dangers.