The whale's sonar system was severely damaged, which may have disrupted its ability to communicate, experts say

The Physeter macrocephalus, which is better known as the sperm whale, or cachalot, is the largest toothed predator and lives in deep seas.

Tragically, a female sperm whale got stranded in Huizhou, Guangdong province, on March 12. After three days of joint rescue efforts, the whale failed to make it back to the sea and died in shallow waters.

On the morning of March 12, a fishing enthusiast found a 10-meter-long sperm whale trapped in a fishing net, which was unable to swim out of Daya Bay in the south of the city.

After hearing the news, members of the local fishery administration, professional divers and fishermen rushed to the site to free the whale from the net and help it back to deeper waters.

However, after initially swimming toward the sea, the whale turned around, and despite the best efforts of the rescue team, who used food to urge the whale to swim in the right direction, they were unsuccessful.

Oceanographers suggested there might be something wrong with the whale's sonar system, disrupting its ability to communicate.

The situation continued until the next evening when the whale was led to slightly deeper waters, but it still seemed to have navigation difficulties.

On the morning of March 14, after round-the-clock efforts, the whale was still unable to get itself out of danger, while its health appeared to be deteriorating.

Experts took action by examining the body of the whale to determine the next steps to take. Its respiration rate was falling and its swimming speed was decreasing rapidly.

"The whale is too close to the shore," said Li Songhai, an expert in marine mammals, when he left the site at about 7 pm. "It's not in a good state and its chances of survival are slim."

The rescue team continued in their attempts to lead the whale to the deep sea, and tried several times to feed it, but their efforts ended in failure.

The whale seemed drained by the events of the long night. On the morning of March 15, after careful examination, experts announced that the whale had died, perhaps due to its poor physical condition, exhaustion, or after becoming stranded in shallow waters.

At about 4:30 pm that day, the dead whale was transported to shore, soon to be sent to the Huizhou Fishery Research and Extension Center for dissection and further study.

On March 16, during the dissection, experts found that the whale's sonar system was severely damaged, which may have accounted for its inability to swim back to the deep sea.

Later that afternoon, there was a 2m-long well-developed sperm whale embryo found inside the dead whale.

"This might be the first time a sperm whale embryo has been discovered during a dissection," said Dong Shenhan, executive curator of the Museum of Biology at Xiamen University, who was in charge of the procedure.

The pregnant sperm whale will help researchers better understand the habits of a mother whale while foraging, and provide valuable information on how to protect this endangered species.

The embryo and its mother will be made into scientific specimens for future study, a task which may take approximately half a year to finish.

The official cause of the death will be revealed when the dissection is complete.

liuxuan@chinadaily.com.cn