High-speed ships connecting the southwestern Japanese city of Fukuoka and the South Korean city of Busan are having trouble with increasing collisions with whales near Tsushima Strait. Some experts claim that whales collide with ships when they rapidly surface from deep water, while others say female whales raising calves have trouble avoiding fast-moving ships. Ship operators are trying hard to pinpoint the cause. Some experts say, however, accidents of this kind are unavoidable to some extent. The service jointly run by Japan's Kyushu Railway Co. and South Korea's Miraejet Co. normally provides five round trips a day. Their passenger…