This contention was widely disputed, not least because only one of the four species of dolphins the fishermen held responsible, the false killer whale, eats yellowtail and even then only as a relatively small component of its diet.
Many scientists argued that the decline was more likely to be the result of a combination of factors. The large net fisheries in the area, operated by Korea as well as Japan, probably over-exploited the local fish stocks. These may already have been affected by pollution and the sudden occurrence of a natural, though unusual, warm ocean current which began to flow through the area in the early 1970s, displacing the colder, more nutrient-rich, waters of the region.
Nonetheless, the fisherment remained convinced that the dolphins were responsible and, by way of a solution, began driving large numbers of the dolphins into bays and killing them.
Between 1976 and 1982, the Iki Islanders killed at least 4,147 bottlenose dolphins, 953 false killer whales, 525 Risso's dolphins and 466 Pacific white-sided dolphins.
The despair of the Katsumoto fishermen was understandable. Their own local laws prevented them from hunting yellowtail by any method other than hooks and lines, which meant that they were unable to compete with the large-scale commercial net fisheries.
In 1977, the fisherment even invited television cameras to film them killing the dolphins, believing that this coverage would generate sympathy for their plight. Instead, scenes of the carnage attracted attention and condemnation from all over the world. This came as a great shock to the Iki islanders, who genuinely couldn't understand why their actions should be considered so controversial.
Then suddenly in 1982, for reasons that are unknown, the dolphins stopped appearing in such large numbers around the yellowtail's breeding grounds. Today, some dolphins are almost certainly still taken in the waters around Iki, but the mass slaughter appears to be a thing of the past.
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