Off-shore Activities and Sources of Pollution

Oil and chemical spills and the deliberate discharge of oily ballast water by ships pose a potential, but poorly documented, threat to marine and coastal habitats. This threat, though important, is thought to be less significant than land-based sources of pollution.

Oil or chemical spills can smother habitats and associated organisms. Studies of the impact of oil discharges into the Arabian Gulf during the Iran-Iraq and Gulf Wars indicate that spills are associated with short-term declines in many fish and other species. In 1986, a major spill off the mouth of the Panama Canal was linked to significant losses in diversity of corals and losses to the extent of coral cover in affected areas.

The discharge of ballast water from ships may pose a more significant threat to some marine habitats as a primary vector in the transport of invasive alien species, rather than as a result of the direct threat created by its chemical contents.