NAGASAKI (Kyodo) High-speed hydrofoil ships ferrying passengers between Fukuoka and Busan, South Korea are increasingly running into whales near the Tsushima Strait -- a problem some fear will put them out of business.
The operators of the ships are trying to pinpoint the exact cause of the accidents, but some experts say they may be unavoidable.
Some say the collisions are caused when whales rapidly surface from deep water; others say females raising calves can't avoid the fast-moving ships.
The international ferry service is jointly run by Kyushu Railway Co. (JR Kyushu) and South Korea's Miraejet Co. The companies make five round trips a day.
"Jetfoil" boats have hydrofoils mounted in the front and back that allow them to skim the waves at more than 80 kph as their hulls float 2 meters above the surface.
According to JR Kyushu, there have been six collisions involving jetfoils since December 2004 -- four this year alone.
In South Korea, about 30 people were injured when the Kobee, a high-speed boat, was apparently hit by a whale.
Tsutomu Tamura, head of the Ecosystem Section at the Institute of Cetacean Research, said beaked whales feed deep in the sea and may have failed to dodge the boats when they came to the surface for air.
Akira Takemura, a professor at the Faculty of Fisheries, Nagasaki University, said the frequency of collisions in the spring is something the companies should pay attention to.
"Spring is the time when humpback whales that have raised their calves in waters near Okinawa and Taiwan travel north through the Tsushima Strait," he said. "It is possible that humpback whales traveling with calves, which move relatively slowly, may have collided with the boats."