Scientific Exploration丨China’s first major rescue: How to find an escape route for whales away from human interference?

At 5:30 in the morning of April 20, the rising sun broke through the thick clouds and dyed the waters of the Nanjiushan area of ​​Xiangshan Port at 30° north latitude orange-red. A huge black figure swam freely in the sea, and the rescue boat guarding nearby looked particularly small in comparison.

Seeing this scene, the rescue workers on the scene breathed a sigh of relief. The rescue boat followed and escorted it for more than half an hour. Finally, the people on the boat saw it flick its tail, dive into the seabed, and disappear in the vast sea of ​​Nanjiu Mountain...

Just the day before, this sperm whale, which was more than 19 meters long and estimated to weigh over 50 tons, was found stranded on the mudflats of Banbianshan Sea Area in Shipu Port, Xiangshan, 20 nautical miles away from this sea area, by local fishermen. It was struggling and on the verge of death.

The full-scale rescue operation lasted 21 hours, starting from the time the alarm was received at 8:40 a.m. on April 19 and the start of the rescue at 9:10 a.m.

During this period, many rescue workers were busy all night, marine experts from all over the country offered suggestions, and countless netizens were worried about the safety of the sperm whale.

Ultimately, this rescue broke China's record of having no successful rescues of stranded sperm whales.

More people are concerned about whether the sperm whales can survive after returning to the sea. Zhou Jiajun, an animal expert at the Zhejiang Forest Resources Monitoring Center, was invited by the Second Institute of Oceanography of the Ministry of Natural Resources to participate in the rescue. He stayed up all night, as he wrote on his Weibo:

Rationally speaking, it is too early to announce that the sperm whale has been successfully rescued. After all, there are no conditions or capabilities for a comprehensive physical examination, the cause of the stranding is unknown, the physical injuries during the stranding are also unclear, and there is a possibility of a second stranding.

However, the sperm whale rescue operation has achieved great and phased success. The experience accumulated from this rescue operation will become a model for rescuing large stranded whales.

I really can't help but praise Xiangshan's operation this time!

Sperm whales on the brink of death

A huge rescue team gathered around it

If we review this rescue operation from Zhou Jiajun's perspective, we can say that it was like walking on thin ice, because there is no standard plan for the rescue of giant whales, and any problem with any detail may lead to the failure of the entire rescue. Although he had rich experience in whale rescue, he was as nervous as riding a roller coaster during this rescue.

It was already the evening of April 19 when Zhou Jiajun arrived at the rescue site. It was already dark and nine hours had passed since the sperm whale was discovered stranded.

He quickly determined that this was a male sperm whale, and that it was in very bad condition, as its genitals, which were supposed to be inside its body, had prolapsed and its mouth was wide open, which were all signs that the whale was in the dying stage.

"When I first saw the images sent back by the drone, my heart sank. I even thought that the sperm whale could not be saved." When he heard the feedback from the rescuers in the front that the whale's nostrils were still flaring weakly, a thought flashed through his mind: as long as he is alive, there is hope.

Previously, local fishery, ocean, public security, fire and other departments jointly carried out the first rescue operation, but because the whale was too large and the tide receded too quickly, the joint rescue team tried several times to tow it away from the beach with a speedboat, but all failed.

The low tide lasted for more than six hours from 10:07 a.m. to 4:31 p.m., during which the tide receded and the sperm whale, whose body was partially immersed in the seawater, faced the most severe test:

First, the skin. The weather was fine that day. Although sperm whales are mammals and can breathe in the air, their skin has adapted to the ocean but not to the sun and drought. Once exposed to the air, it will peel off in a state similar to severe burns.

Secondly, the internal organs. It is almost impossible for humans to weigh a living sperm whale, and the weight of the stranded sperm whale can only be estimated by analogy: a dead sperm whale with a length of 19.2 meters was measured to weigh 70 tons. The length of this stranded sperm whale was also measured to be more than 19 meters, and the weight was estimated to be at least 50 tons, and may even exceed 70 tons. Once such a giant body is out of the buoyancy of the sea, the damage caused by the weight squeezing the internal organs may also lead to exhaustion and suffocation.

Zhou Jiali said that the rescue operation in Xiangshan was very scientific. During the first rescue, the rescuers found that the whale was moving with huge amplitude in the water and it was impossible to fix the ropes, so they decisively stopped the rescue and waited for a better time to rescue.

At about 4 p.m. that day, the tide had receded to its lowest point. Slowly, the entire sperm whale emerged from the water, lying on its left side in the mud. Although the towing rescue operation was stopped, efforts to buy time for the sperm whale to survive did not stop.

The local fishery administration, fire department, Blue Sky Rescue Team, and fishermen gathered around the sperm whale, pouring water on it to lower its body temperature and keep its body moist. At the reminder of fishery experts, everyone was especially careful to avoid sensitive parts such as the nostrils and eyes.

Wang Yunxiang, the station chief of Shipu Station of Xiangshan Fire Brigade, was also in the rescue team, but he was a little anxious. He and his teammates rushed to the scene early in the morning with rescue equipment. Before setting off, they also brought two motorized pumps to pump water to replenish the stranded whale, and also brought water rescue suits and kayaks, but when they arrived at the scene, they were worried: the beach where the whale was stranded was far away from the equipment-carrying vehicle, and they had to carry these equipment to cross a large reed marsh and then cross a nearly 800-meter-long beach to reach the whale, so the group had to abandon the equipment and walk through the knee-deep mud on the beach to get to the sperm whale.

In the most difficult mudflat drag rescue

The sperm whale seemed to understand human nature and cooperated throughout the process.

As time passed, the sperm whale gradually became weaker. Wang Zhiyuan, a veterinarian at Ningbo Ocean World, gave the sperm whale an infusion to fight inflammation. Everyone was waiting for the second rescue moment: the next high tide.

The wait was unbearable, and the atmosphere in the rescue command center was tense. At 8 p.m. the night before, the second rescue plan was being discussed.

Based on the evaluation of the sperm whale's length and weight, Zhou Jiajun and the experts all agreed that this was an adult male whale. After comprehensive analysis of factors such as the on-site environment and the whale's condition, everyone tended to adopt the towing solution: tie a fixed rope to the whale's tail and use the power of the boat to slowly tow the whale back to the deep sea.

But this plan also needs to consider many risks:

If a large ship is used to tow the whale, and the sea water is not deep enough, the ship will run aground if it gets close. The large ship cannot maintain a low speed when towing, and may break the whale's tail vertebrae, causing serious injury or even death to the whale.

If a small boat is used for towing, the total displacement will be 50 tons, but the whale's weight is definitely more than 50 tons. During the towing process, if it struggles a little and swings its tail, it can capsize the small boat and put the rescuers in danger.

Where should the towing rope be tied? Because the rope cannot pass through the whale's huge body, it can only be tied to the tail, which may also cause the tail vertebrae to be broken.

The final solution is to ensure the safety of the whale and try to tow it with a small boat. If there is a danger to people during the rescue process, decisively abandon the rope to ensure safety.

Finally, as high tide approached, the rescue went as planned. Zhou Jiajun recalled that every possible detail was taken into consideration.

Firefighters first wrapped a blanket around the whale's tail handle, and then tied an easily removable escape rope (one end of this rope can be tightened for towing, and the other end can be loosened, so that when reaching deep water, the other end can be loosened to separate from the whale.

At the same time, the whale was also tied with a red signal buoy light for easy observation.

After completing the preparations, all personnel evacuated the scene together because the high tide would pose a threat to rescue workers.

At 10 o'clock in the evening, the highest tide level soon arrived, and the rescue boat began to tow the sperm whale, slowly moving towards the open sea, slower and slower.

Although Zhou Jiajun has had many experiences in rescuing cetaceans, this was the first time he felt that whales might really have the intelligence to understand humans, or maybe it was a matter of luck. During the most difficult dragging process on the mudflat, the sperm whale was very cooperative and did not move until the rescue boat stopped in the sea water. Then it began to swing its tail fin in the water, gradually regained its body balance, and began to exhale and spray out high columns of water!

At that moment, the scene and the rescue command center were in an uproar. There was hope that the sperm whale would be rescued!

After that, the rescue boat slowly towed the sperm whale away from the stranded location at a speed of 1 to 2 knots (1.8-3.6km/h) and headed towards the open sea.

How to feed this sperm whale

Looking for a route out of trouble, away from human interference?

The whale was in very good condition during the entire towing process. Its tail was swinging, its head was constantly tilted upwards, and it sprayed water from time to time to breathe. It seemed that its vitality was constantly recovering.

Through the images sent back by the rescue ship, people were shocked by the tenacity of the sperm whale. Firefighter Luo Cheng on the rescue ship kept his eyes on the sperm whale and he even felt that the whale tilted its head in response to them on the boat.

At that moment, everyone was willing to believe that all things have spirits.

But the rescue is not over yet.

Sperm whales live in the deep sea far away from humans and coastlines. The depth of the sea water where they hunt for food is at least 100 meters deep, because the squids they like live in the sea water in this range. Therefore, it is important to find a truly escape route for this sperm whale away from human interference.

There is a busy westward route near the coast of Xiangshan, and the local fishery administration department recommends releasing the fish in the open sea 20 nautical miles away.

At the same time, considering the voyage time, the release can be carried out at sunrise and at the lowest tide, which makes it easier to observe the whale's condition after release and further reduces the probability of it being stranded again.

The experts unanimously agreed and suggested the need to stop the ship regularly to observe the physical condition of the whales when towing stops.

The time after 3 a.m. was even more torturous as the tugboat entered a sea area where the signal was unstable. During this period, the tugboat lost contact with the command center for a while.

It wasn't until 5:30 in the morning that the good news finally came.

Why are stranded sperm whales so difficult to rescue?

It is a common understanding in the world that stranded large whales are extremely difficult to rescue, because they are too large to be effectively moved, and even approaching them rashly may be dangerous.

Therefore, there are many sperm whale stranding incidents around the world, but very few have been successfully rescued. The sperm whale stranded in Xiangshan this time was completely out of the water at low tide. Because of this, this rescue also made many people feel that it was a miracle.

Acoustic repelling and induction are commonly used rescue methods for whales and dolphins when they are about to run aground in shallow waters. In the water, vision is limited by factors such as visibility. Toothed whales use echolocation more often to detect the environment and find food, so they are more sensitive to underwater sounds. However, this kind of rescue is suitable when the whale is not completely out of the water. It is difficult to use it in situations like the stranded whale in Xiangshan, which is completely out of the water.

Chen Jian, director of the Marine Biology Museum of Zhejiang Ocean University, also paid attention to the rescue. At the beginning, he was not optimistic about the rescue because there had been no successful cases of rescuing sperm whales in China.

In 2013, several sperm whales were stranded in Yancheng, Jiangsu, and none of them could be rescued.

On March 12, 2017, a sperm whale swam into the waters off Daya Bay. It was injured and tangled in fishing nets. Although local departments worked together to rescue it and helped it move to deeper waters, it ran aground again and stopped breathing as more and more people gathered to watch. What was even more worrying was that during the autopsy, experts found a baby sperm whale in its belly.

Zhou Jiajun, who has participated in many cetacean rescues, has a more personal experience of this. Usually, the stranded cetaceans are relatively small. For example, on July 11, 2021, a group of melon-headed whales were stranded in the coastal waters of Taizhou. He also participated in the remote rescue. Melon-headed whales are small individual cetaceans.

People in Linhai, Taizhou are rescuing melon-headed whales

Compared with the rescue of giant stranded whales, the rescue of small stranded cetaceans also faces difficulties: sperm whales are huge in size, and the advantage is that they are not afraid of humans. For example, this sperm whale did not overreact when humans rescued it; but small cetaceans are different. They are timid and easily have stress reactions, and in severe cases even die.

On November 10, 2021, an East Asian finless porpoise strayed into an inland river and wandered around Nanshaoxi River in Yuhang, Hangzhou for many days. Zhou Jiajun also participated in the rescue. Unfortunately, during the transportation of the finless porpoise, the finless porpoise had a severe stress reaction due to fear and eventually died.

Every time they rescue animals, rescuers like Zhou Jiajun keep thinking: How can we humans better rescue these animals in danger? How to deal with stress during the rescue process? Should we use tranquilizers in advance? But this is also an area worth discussing and studying: how to use tranquilizers, how to control the dosage, and how to minimize secondary damage?

In Zhou Jiajun's words, there are still too many unknown areas for humans to explore when it comes to cetaceans.

Can the sperm whale’s life be smooth after returning to the sea?

Sperm whales that return to the sea may be stranded again. Zhou Jiajun is not the only one who has such concerns. Chen Jian also thinks so. The two have the same reason: sperm whales generally live in deep waters of the ocean because there is the food and seawater depth they need. Normal sperm whales simply cannot come to the coast so close to the land. If it appeared on the coast, something must have gone wrong.

The reasons why whales get stranded are still a mystery to humans, but some reasons can be summarized from existing experience:

One is water pollution. Many stranded whales have been found to have plastic, fishing nets and other garbage entangled in their bodies, and wounds caused by being entangled and torn by these garbage can often be seen on the whales.

The second is noise pollution. The hearing of whales has long been adapted to the background sounds of the natural environment, and they often join in this music. Underwater, they make a series of sounds of different frequencies to communicate with their peers. These sounds include low-frequency (generally less than 1000 Hz) groans, grunts, collisions, and knocks, as well as high-frequency (generally above 1000 Hz) screams, whistles or "singing". However, the noise generated by human fishing boats, underwater blasting and other operations can cause harm to whales and may also cause them to lose their way and run aground.

The third is to rescue fellow whales. Some whales with strong sociality (such as pilot whales) may be reluctant to abandon stranded individual members, which may eventually lead to the large-scale stranding of the entire whale group.

The fourth is organic damage, such as sonar damage (just like blindness), loss of direction and stranding.

The most likely scenario for the Xiangshan sperm whale stranding this time is the fourth one. But the worst scenario is also the fourth one. If the whale's sonar system is damaged, it is very likely to strand again even if it is released this time.

Based on this consideration, Zhou Jiajun admitted that the most regrettable thing about this rescue operation was that no positioning beacon could be installed to track the subsequent movements of the sperm whale. There are two reasons. First, the beacon device. The relevant units in Zhejiang Province did not have the equipment. During this rescue, when the experts from the Institute of Deep-sea Science and Engineering of the Chinese Academy of Sciences in Sanya arrived, the sperm whale had been dragged to the open sea. Second, even if there was equipment, if you want to install it on a national first-class key protected wild animal, you need the approval of the Ministry of Agriculture and Rural Affairs, which is too late in terms of procedures. We still need to strive to promote this aspect of work in future rescues.

Where will this lucky sperm whale go?

Netizens who followed the rescue of the stranded whale in Xiangshan expressed their feelings: I hope we will never meet again in our "whale" lives. Although it is best not to meet, it does not prevent us from caring about it. What will happen to this sperm whale in its future life?

To answer this question, we must start with understanding sperm whales. Only those who have seen sperm whales in person can feel how insignificant humans are. Sperm whales are the largest existing toothed whales in the world. They mainly move in the deep ocean in the twilight zone (generally refers to the depth from 200 meters to 1,000 meters where the light is dim). They are widely distributed and numerous, but mysterious and unpredictable. They are an important part of the vertical energy flow of the marine ecosystem.

But in this population, females and males have completely different lifestyles. Female sperm whales live in tropical waters (which is why there are almost no female sperm whales along the coast of my country), while males travel all over the world. They can adapt to a wide range of sea temperatures and can swim from tropical waters all the way north to very cold polar waters, which means they have traveled halfway around the world.

Males come to tropical waters during the mating season. They make complex, regular sounds with a wide frequency range in order to win the favor of females and find a partner to give birth to the next generation. After the sperm whale baby is born, the sperm whale mother will continue to stay in the tropical waters to accompany the sperm whale baby to grow up, while the sperm whale father will leave and head north to the polar regions. This behavior of male sperm whales is biologically considered reproductive migration.

Sperm whales usually live 60 to 70 years, sexually mature males between 18 and 20 years old, and females mature earlier, at 12 to 13 years old. Once they become adults, they continue the way of life of the previous generation.

Judging from its body size, the sperm whale stranded in Xiangshan is an adult, and its teeth are sharp and unworn, indicating that it is in its prime. It can be seen that this male sperm whale that appeared in the Xiangshan waters was just passing through the waters of 30° north latitude, and it should not have stopped there. If everything goes well, it may go all the way south to find "love", or it may go all the way north to become a lonely wanderer.

We wish it the best either way, and we just hope it won't continue to linger at 30° north latitude.

Herman Melville praised the beauty of sperm whales countless times in Moby Dick. Humans have too many imaginations and stories about sperm whales. Those who have witnessed sperm whales are all amazed by this elegant creature and realize what a mysterious legend it is in the ocean.

A little science: Why are they called sperm whales?

Sperm whales are whales of the abyss. They hunt in the ocean at a depth of 2,000 meters, using ultrasound to detect the dark environment and chase squid. After two hours of breath holding, deep diving and fighting, they will come to the calm sea surface to rest for eight minutes before sinking again; during these eight minutes of breathing, they will spray 40 water columns up to two meters high, diagonally to the left and front. Compared with the abyss, the sea surface is a bright, warm and peaceful resting place; adult sperm whales with almost no natural enemies may have rested here for 25 million years.

The origin of the sperm whale's name is also very interesting, and it is related to a precious spice called "ambergris". Sperm whales like to eat giant squids, and usually they will swallow the giant squids in one gulp, but the squid's beak cannot digest it, which causes irritation and lesions at the end of the sperm whale's large intestine or the beginning of its rectum, thereby producing a secretion, which gradually forms a substance in the small intestine, which is ambergris. Ambergris itself does not have much fragrance, but when it burns, it exudes a fragrance that is very similar to musk, but more distant than musk. Things that are smoked by it have a long-lasting fragrance, so it is named: sperm whale.

Zhu Yun, editor-in-chief of Chengshi Interactive Ningbo Channel and reporter of Metropolis Express

(Photo courtesy of Xiangshan County Party Committee Propaganda Department and Xiangshan County Fire Rescue Brigade)