Once a substantial threat, by-catch has been reduced from 14,000 striped dolphins a year between 1950 and 1969 in the western Pacific, to a current incidental catch of 2,000 to 4,000 individuals. Fishermen kill dolphins caught in their nets as they present competition for fish (7). Hunting has also been known to take place, particularly in Japan, but is not considered a major threat, and Japan has voluntarily reduced its catch. Water pollution as a result of the release of heavy metals causes lung disease, and the over-fishing of anchovies has harmed populations in some areas (4). In the Mediterranean Sea, a morbillivirus caused the death of more than 1,000 animals between 1990 and 1992. The epidemic was possibly caused by poor environmental conditions (1).