A sperm whale that died after being spotted struggling near the mouth of the Yodo River in Osaka last week was sent to the sea floor Thursday off the Kii Peninsula south of Osaka Bay, the city's ports bureau said.

The around 15-meter-long male whale referred to affectionately on social media as "Yodo-chan" was transported by ship after being attached to 30-ton concrete blocks to weigh it down once in the water.

According to the bureau, the vessel carrying the whale's corpse was towed by a tug boat in the early hours of Thursday from a quay near the mouth of the Yodo River.

The vessel was taken south between Wakayama and Tokushima prefectures and the cetacean was deposited into the water just past 3 p.m.

Photo taken from a Kyodo News helicopter on Jan. 19, 2023, shows a dead whale being sent down to the sea floor with 30-ton concrete blocks from a vessel off the Kii Peninsula, western Japan. The 15-meter-long male sperm whale, which was first sighted on Jan. 9 near the mouth of the Yodo River in Osaka, became progressively weaker and was confirmed dead four days later. (Kyodo) ==Kyodo

The whale, which weighed 38 tons, was first sighted on Jan. 9 after it strayed into the mouth of the river. It became progressively weaker, and experts confirmed on Friday it had died.

Osaka Mayor Ichiro Matsui told reporters on Tuesday that while there had initially been talk of temporarily burying the whale's body on land to reduce it to a skeletal specimen for display in a museum, the plans were abandoned due to the government receiving no requests for the animal's remains.

According to the coast guard, it is rare for whales to be sighted in Osaka Bay. The bay is largely enclosed by Awaji Island, leaving two narrow passages to the north and south -- the latter of which leads to the Pacific Ocean.

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