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Why do whales run aground? What are some ways to rescue stranded whales?

author:Shaanxi Science Popularization

The morning of April 19

A whale in Ningbo, Zhejiang Province

The sea near Xiangshan County was stranded, in the early morning of the 20th

After being towed to the release area by local rescue forces

The whales have divened and swam back to sea on their own

Why do whales run aground? What are some ways to rescue stranded whales?

Image source People's Daily

When it comes to whale strandings, many friends may think of last year's swarm cetacean strandings, from June to October 2021, a total of 7 swarm cetacean strandings occurred along the coasts of Fujian and Zhejiang. The stranding involved a total of 47 animals from 4 cetacean species, including melon-headed whales, rough-toothed dolphins, bottlenose dolphins and Brinell's whales.

Why do whales run aground? What are some ways to rescue stranded whales?
Information on the mass cetacean stranding incident along the coast of China from June to October 2021, source of voice of the Chinese Academy of Sciences

Today we will study it:

Why do whales run aground?

What are some ways to rescue stranded whales?

What else is there to know about whales?

Cetaceans stranded

Cetacean stranding refers to the presence of cetaceans in places where they should not be, such as species living in deep offshore areas that appear in shallow waters near shore. The most common strandings usually occur on beaches as well as in shallow waters.

The causes of cetacean strandings are diverse, including both themselves and external factors (natural and human factors).

Why do whales run aground? What are some ways to rescue stranded whales?

Image source People's Daily

1. Animals may cause animals to run aground due to their own navigation disorders, age, diseases, community activities, etc

The smooth progress of cetacean echolocation is inseparable from the acoustic emission (sound) and sound reception (hearing) parts, when any part of the function out of the problem will directly affect the navigation of animals. In addition, some of the loss of hearing ability (deafness) that animals may experience in old age may also most likely lead to stranding of animals.

In social cetaceans, when individuals or parts of the group are stranded, other individuals in the group may also be stranded (either out of blind entourage or to rescue those stranded individuals).

Why do whales run aground? What are some ways to rescue stranded whales?

Graph source network

2. Natural environmental factors including solar motion, global or regional climate events, coastline topography, earthquakes and typhoons can also lead to stranding

The movement of the sun causes the flow of energy hitting the Earth to change and thus change the Earth's magnetic field, which in turn causes cetaceans that need to rely on the Earth's magnetic field for navigation, such as sperm whales, to get disoriented and eventually run aground.

During climate events, the continuous latitude and meridian monsoons in southern Australia are associated with cetacean stranding events. The special topographic structure of some coastlines can seriously interfere with the echolocation signals of cetaceans and form a sound blind area, which in turn can lead to the stranding of whales.

Environmental events, including earthquakes, typhoons, toxic and harmful blooms, etc. may also cause cetaceans to run aground. Predator hunting, such as killer whales, can also cause cetaceans to flee and panic and lead to stranding.

Why do whales run aground? What are some ways to rescue stranded whales?

Image source Popular Science China

3. The stranding of cetaceans caused by human factors mainly includes fishing activities, marine litter, and water pollution (such as water noise pollution).

Long-term exposure to water noise, such as ship noise, can cause cetaceans to run aground. In addition, the use of high-energy pulsed artificial sonar, such as various offshore oil and gas exploration and military activities, can also lead to the stranding of cetaceans.

In December 2009, seismic survey activities in the waters of the Adriatic Gulf in southern Italy were identified as the cause of the stranding of sperm whales in the waters concerned. In July 2004, a massive runaway of nearly 150-200 melon-headed whales in the waters of The Hawaiian island of Kauai was also linked to military exercises. Because on the same morning as the stranding, a joint military exercise was conducted in the relevant waters and a strategic intermediate frequency sonar was launched on the water body.

Why do whales run aground? What are some ways to rescue stranded whales?

Graph source network

Rescue methods for cetacean strandings

Experts said that according to the physical condition of different stranded whales and dolphins, there are three main ways to rescue them:

• Release cetaceans directly into the ocean if their physical condition permits;

• Leave stranded cetaceans with care such as staying hydrated and allowing them to swim on their own after high tide;

• Transfer the badly injured stranded cetacean to an artificial environment and release it into the ocean after it has recovered.

Why do whales run aground? What are some ways to rescue stranded whales?

Graph source network

Hao Yujiang, an associate researcher at the Institute of Hydrobiology of the Chinese Academy of Sciences, said that because of the large size of the cetaceans, once stranded, it is easy to fall into the mud and sand of the tidal flats, and it usually takes hours or even longer to rescue them. In order to keep it safe from life danger, the following points should be paid attention to during rescue:

• Align the body of the cetacean with the breathing hole facing upwards to ensure normal breathing;

• Clean the breathing holes to prevent muddy water from entering the respiratory tract or even in the lungs and causing infection, which can lead to death;

• Since cetaceans do not have limbs to support their bodies, the chest and abdominal cavity are subjected to a lot of pressure when stranded. Therefore, it is necessary to make it in shallow water as much as possible, with the help of buoyancy to support the body;

• Cetaceans' skin cannot withstand prolonged dryness, keeping their skin moist and not exposed to direct sunlight.

Why do whales run aground? What are some ways to rescue stranded whales?

Image source Guangming Network

Whale trivia

1. Whale fall and whale explosion

Whales die in the ocean to produce whale drops, and their corpses can support a circulatory system dominated by decomposers for up to a hundred years, which is called an "oasis" of deep-sea life along with hot liquid and cold springs.

If a whale dies on the beach, it is often greeted by a terrible "whale explosion". Whale explosion is a whale explosion, which will spew out a large amount of rotten flesh and poisonous gases, and the ejection after the whale explosion will also pollute the surrounding environment and produce a strong odor that can last for several months.

Why do whales run aground? What are some ways to rescue stranded whales?

Source Science Compound

According to Zhang Tangming, a specimen maker at the Shanghai Science and Technology Museum, there are two causes of whale explosions. The first is that after the whale dies, the bacteria inside the carcass multiply rapidly. Due to the abundance of whale fat, bacteria break down these nutrients to produce large amounts of ammonia and carbon dioxide.

"On the other hand, the whales themselves are active in the deep sea, and the pressure of the deep sea is strong, so the whale's skin is very tough. These gases accumulate more and more in the whale's body, like blowing a balloon bigger and bigger. When these gases find a vent, it causes whale explosions. ”

2. Biomimetic application of whales

Whales not only maintain ecological balance, but also have great significance in biomimicry research and application.

Now the "streamlined" bow of large ships is modeled after the size of whales, and the speed is greatly improved compared to the previous pointed ships. Contemporary nuclear submarines launch missiles under the ice, and by strengthening the strength of the material and imitating the operation of the shape of the whale's back, the "whaleback effect" when breaking the ice is achieved.

Source: Shaanxi Science Popularization

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