Among the more than 30 dolphins that washed up on the shores of coastal Chiba Prefecture earlier this week, one had pneumonia and several were pregnant, a Japanese researcher said Friday.
Of the 32 beached dolphins, which were washed up on the shore from Monday through Wednesday, 14 have died. Though surfers have worked hard to return the dolphins to the sea, they have been drifting back ashore in a weakened state.
According to Yuko Tajima, a researcher on marine mammalogy at the National Museum of Nature and Science in Tokyo, which conducted autopsies on six of the dead dolphins, two were pregnant and one of the two was suffering from a severe case of pneumonia.
“It could be because of the spread of diseases in the group, hypothermia and emaciation due to the low water temperature,” Tajima said, explaining reasons why so many dolphins had washed ashore. “We’ll continue to analyze what the cause of the deaths was.”
The dolphins, which belong to a species known as melon-headed whales, were found stranded along a 500-meter stretch of beach near Tsurigasaki. The first six dead dolphins were subsequently sent to the National Museum of Nature and Science for further investigation.
“I’m not sure of the reason behind it, so it's a little difficult for me to comment, but I think it's great that the surfers have put in the effort,“ said Akihiro Yoshino, an official at the Ichinomiya Municipal Office.
Melon-headed whales, a member of the dolphin family despite their name, prefer deep subtropical waters and only tend to come close to shore when the seafloor slopes steeply, according to Whale and Dolphin Conservation in the U.K.
