Massive stranding of dolphins. Why do dolphins wash ashore? Hundreds of pilot whale dolphins could have washed ashore due to the illness of their leader Why they wash ashore
Well, it has just been reported that in New Zealand, about 200 more black pilot dolphins have washed ashore in the area of Cape Farewell in the north South Island. All TV channels show how volunteers are trying to save them, pouring water on them and wrapping them in wet rags.
At the same time, a day earlier, about 400 pilot whales stranded in the same area. As reported, most of them, up to 300 individuals, were already dead.
Such cases are not the first in history. Why is this happening?
People have found sea animals that inexplicably washed ashore at least since the first century AD - this is evidenced by ancient Roman and ancient Greek documents. Today, marine biologists undertake to name the reasons for only half of such incidents, and these reasons are very different.
In 2002, 55 whales washed ashore on Cape Cod Bay. Thanks to the efforts of American rescuers, 46 animals were saved. People doused the whales with water and covered them with wet towels, preventing them from overheating. When the tide came in, the whales were dragged into the water. Alas, some of these sea animals never saw the tide.
In 2004, 15 whales washed up on the shores of two islands in the Canary archipelago. Only three of them were saved.
In June 2005, about 160 whales washed up on the Australian coast. Rescuers, with the help of volunteers, did not allow the five-meter “fish” to die.
In October 2005, 70 whales died on the beaches of the island of Tasmania (Australia).
In March 2007, 12 whales washed ashore on one of the Galapagos Islands. Despite all the efforts of rescuers, seven animals died.
In 2012, only on the Cape Cod Peninsula 177 common dolphins ran aground and 124 died, according to Associated Press reports. The report also mentioned that this total number of dolphins exceeds the average of 37 animals recorded in the previous 12 years.
More than 200 dead dolphins have washed up on the beaches of Chiclayo, Peru. IN in this case They found not only dead dolphins, but also dead fish - anchovies. Since this small fish is food for the dolphins, it is possible that they became sick due to these fish, but the cause of the death of the animals remains a mystery.
Why is this happening?
Often this is an injury or illness. An animal that has been attacked by a predator may feel too weak to float, at some point it gives up and allows itself to be carried ashore by the waves. In our case, the leader maritime program World Fund wildlife Konstantin Zgurovsky suggested that cetaceans could have been stunned by seismic exploration or underwater acoustic systems warships. According to the expert, there are also suggestions that animals are infected with worms or poisoned by pollutants entering the ocean, such as heavy metals.
Climate cycles could change the direction of movement of fish and other creatures that dolphins feed on. Dolphins, chasing prey, could swim close to the shore and land on land. This makes sense considering that sardines and other fish have been found washed ashore with dolphins in Peru.
Much more mysterious are cases when a whole group of animals washes up on the shore. One explanation that scientists offer is that whales and dolphins, which hunt and migrate in small herds, are victims of their own social structure. If the leader or dominant animal is cast ashore due to illness or injury, the rest of the group may follow. Whales always help out a relative from their pod. If one of the whales wanders into shallow water by mistake, it immediately begins to send signals to its relatives, and they rush to help. Alas, the whales, instead of saving their comrade, get into trouble themselves.
Another version is that the herd swims too close to the shore and does not have time to return during low tide.
In some cases, marine animals commit mass “suicides” shortly after the active use of military sonars nearby. In 2000, in the Bahamas, for example, 17 animals of four different types(beaked whales, toothed whales, dwarf minke whales and spotted dolphins) were found on the shore within 36 hours - on the day the sonar was used in these places and on the following day.
Research conducted by the National Oceanic and Atmospheric Administration after this incident showed that the most probable cause there were naval echolocation devices. Research data suggests that sonars had an impact on both the physical condition and behavior of marine animals.
Whales are excellent at navigating the ocean, so biologists say that in their brains magnetic compass, thanks to which these Marine life can navigate by magnetic field Earth. If a geomagnetic obstacle appears in front of whales, their internal compass becomes faulty and they begin to swim in the wrong direction. It is known that rescued whales often wash ashore again. Perhaps this is precisely explained by the breakdown of the compass - the whales returned to the water, but could not find their way.
There is also a theory of noise. This theory is the most popular today. Scientists claim that whales and dolphins are being killed by the deafening roar of submarines. Losing their hearing, whales lose their bearings and wash ashore. An examination of the bodies of the ejected animals suggested that the cause of suicide was decompression sickness. This malaise occurs when there is a sharp decrease in external pressure. Caisson disease is a disease of divers, pilots and workers who work in caissons (underwater work chambers).
A strong noise underwater frightens the whales, and they begin to rise up too quickly - there is a sharp decrease in external pressure. This provokes the occurrence of decompression sickness in whales. Echo sounders, radars, sonars, missiles, and submarines can scare whales. This version is supported by facts - there are several examples that the release of whales occurred during military exercises using sonars.
It also happens that animals are thrown ashore intentionally - for hunting. Black killer whales, for example, often attack pinnipeds such as seals or sea lions, in the surf zone or almost on the shore itself, where their victims change their mode of movement from swimming to walking and do it rather clumsily. While the animal is trying to get out of the water, the killer whale makes a dash and grabs the prey. After this, she can either wait for a suitable wave, or try to return to the ocean, wriggling her whole body.
Here is video evidence of one such hunt:
But 30 dolphins washed ashore:
Be that as it may, scientists have not yet come to a consensus.
sources
A large-scale disaster occurred in New Zealand - about 400 pilot whales washed ashore, two thirds of them died. New Zealand authorities called the mass stranding of dolphins on land one of the largest deaths of mammals in the history of dolphin observation, reports New Zealand Herald.
Large-scale dolphin stranding in New Zealand | social network
A large-scale stranding of dolphins occurred on the night of February 9-10 on the coast of Golden Bay, located in the north of the South Island of New Zealand. 500 volunteers and nature conservation workers urgently went to help the pilot whales. Local residents, together with rescuers, are trying to refloat the mammals and point them right direction so that they float out to the open sea.
But only 100 dolphins were saved, which continue to amaze with their behavior - the mammals do not want to swim into the open sea, but again change direction and return to the shore, which raises fears that the dolphins may wash ashore again. New Zealand officials and local residents say they have never seen anything like it.
For what reasons the dolphins washed ashore is not yet known. Nature conservation experts note that New Zealand often becomes a place where whales and dolphins beach themselves, but there is still no exact answer as to what could be the cause of such mass suicides of mammals that occur from time to time in different corners globe. Experts explain that, as a rule, if one dolphin washes up on the shore, others from the pod will try to help it and ultimately share its fate.
Massive dolphin stranding in New Zealand (video):
More than 400 black dolphins have washed ashore on a beach in New Zealand, most of them already dead. Volunteers try to save the animals, but they come back again. Medialeaks figured out the reason for this behavior of dolphins and what is happening on the shore now.
416 pilot whales - black dolphins, or pilot whales as they are called in English-language sources - washed ashore on the evening of February 9 in Golden Bay on South Island in New Zealand. About 300 animals died before people discovered them. This is one of the largest mass dolphin suicides in history. last years, reports the New Zealand Herald.
About 100 dolphins survived, and hundreds of volunteers came to the beach to save them: the animals were doused with water and covered with a wet cloth to cool them down until the morning tide. The dolphins were sent back to the ocean on the morning of February 10, but, unfortunately, most of them jumped out again.
About 500 volunteers have already come to save the pilot whales. They continue to maintain the normal condition of the dolphins and hope that after the next tide the animals will swim away, writes Nelson Mail. Animal rights activists explain this behavior of pilot whales due to deep social attachment: the survivors do not want to part with their flock.
Dolphins can also be confused by the Farewell Spit, which is surrounded by a bay where the animals were thrown out.
Golden Bay and Farewell Spit
Volunteers post photos of dolphins on Instagram and say that the sight they saw on the beach was the saddest thing they saw in their lives.
“On our trip yesterday we learned that 416 pilot whales stranded near Farewell Spit and 75% of them did not survive. It didn't take Mitchell long to make a decision and we got into the car and drove 4.5 hours to Farewell Spit. It's a great feeling to be here and help the whales shoulder to shoulder with people of different nationalities until the very end..."
Struggling to understand such a tragic loss in nature. At whale stranding in GB today pic.twitter.com/XzkmfuwBKq
“I cannot understand such a tragic loss in nature. Today on the beach of Golden Bay, where the dolphins washed up.”
“About 400 dolphins stranded near Farewell Spit last night. One of those touching moments when volunteers without special clothes hug to keep warm as they leave cold water, where they are still trying to save as many as possible."
Representatives of the animal protection organization Project Jonah, which coordinates the work of volunteers, explain that according to statistics, about 300 whales and dolphins wash ashore in New Zealand per year, most often this happens when the animals incorrectly determine the position of the shore due to extraneous sounds. and seismic waves.
Experts cannot determine exactly what caused the tragic phenomenon. According to one version, the leader of the dolphins made a mistake with echolocation and incorrectly determined where the shore was, and other animals followed him. Scientists also suggest that the dolphins could have jumped out due to illness or injury.
In the fall of 2016, one of the employees of the Primorsky Aquarium, in which 14 animals died over three years,... According to him, dolphins and seals are fed rotten fish, but management spends money on their own comfort.
Volunteers and rescuers battled to save the lives of stranded pilot whales on New Zealand's South Island today, but only about 100 of the animals were saved.
Such massive strandings of cetaceans rarely occur. As a rule, their number does not exceed several dozen, Mukhametov said.
“It is characteristic that it is not coastal animals that are usually thrown away, but pelagic animals - animals of open spaces. Animals that live near the shore, for example, our Black Sea bottlenose dolphins, are less likely to be thrown out,” the scientist emphasizes.
Why do they do this
There are many hypotheses as to why whales and dolphins wash ashore. But scientists still don’t know the exact reason, Mukhametov emphasizes.
“Most likely, the animals are sick. In first place we can put diseases of the hearing and echolocation apparatus. If it is disrupted, animals may not feel like they are stranding themselves. When cetaceans are stranded en masse, most likely, the imitation reflex is triggered: if a sick leader of the herd is stranded, his relatives follow him,” Mukhametov said. The disease can be caused by viruses and microbes that marine mammals susceptible no less than terrestrial ones.
Thus, in the 80-90s of the last century, thousands of animals died in the North Atlantic due to a virus that came with North Sea, spread to the North Atlantic, the Caribbean, and then spread to the Mediterranean and Black Sea, notes Mukhametov.
Memory of land and geomagnetic lines
Among other hypotheses, the scientist names changes in geomagnetic fields. “There is an assumption that they sense geomagnetic fields and navigate by them. If geomagnetic disturbances occur, this leads to ejections,” Mukhametov said.
There is a version that the echolocation abilities of cetaceans may malfunction near the coastline. “Echolocation misinforms animals near cliffs or flat surfaces - shores, beaches - and they are thrown out,” explains the expert.
Some cetacean researchers believe that animals have a “historical memory” of land. That is, marine mammals tend to throw themselves onto land when they feel unwell.
“There is an assumption that cetaceans, when they feel bad, tend to throw themselves on the ground because they evolutionarily feel that it is better on land than in water. After all, these are secondary aquatic animals, their ancestors existed on land,” Mukhametov said.
“There was an incident with a combat dolphin while working at the training ground. He was working on the high seas and was very scared of a shark. He rushed to the shore and jumped ashore out of fright. It seems to be an illustration that historical memory makes you rush to the shore when you feel bad,” said the scientist.
Well, it has just been reported that in New Zealand, about 200 more black pilot dolphins have stranded on land near Cape Farewell in the northern part of the South Island. All TV channels show how volunteers are trying to save them, pouring water on them and wrapping them in wet rags.
At the same time, a day earlier, about 400 pilot whales stranded in the same area. As reported, most of them, up to 300 individuals, were already dead.
Such cases are not the first in history. Why is this happening?
People have been finding sea animals that have inexplicably washed up on shore since at least the first century AD, as evidenced by ancient Roman and Greek documents. Today, marine biologists undertake to name the reasons for only half of such incidents, and these reasons are very different.
In 2002, 55 whales washed ashore on Cape Cod Bay. Thanks to the efforts of American rescuers, 46 animals were saved. People doused the whales with water and covered them with wet towels, preventing them from overheating. When the tide came in, the whales were dragged into the water. Alas, some of these sea animals never saw the tide.
In 2004, 15 whales washed up on the shores of two islands in the Canary archipelago. Only three of them were saved.
In June 2005, about 160 whales washed up on the Australian coast. Rescuers, with the help of volunteers, did not allow the five-meter “fish” to die.
In October 2005, 70 whales died on the beaches of the island of Tasmania (Australia).
In March 2007, 12 whales washed ashore on one of the Galapagos Islands. Despite all the efforts of rescuers, seven animals died.
In 2012, on the Cape Cod Peninsula alone, 177 common dolphins ran aground and 124 died, according to reports from the Associated Press. The report also mentioned that this total number of dolphins exceeds the average of 37 animals recorded in the previous 12 years.
More than 200 dead dolphins have washed up on the beaches of Chiclayo, Peru. In this case, they found not only dead dolphins, but also dead fish - anchovies. Since this small fish is food for the dolphins, it is possible that they became sick due to these fish, but the cause of the death of the animals remains a mystery.
Why is this happening?
Often this is an injury or illness. An animal that has been attacked by a predator may feel too weak to float, at some point it gives up and allows itself to be carried ashore by the waves. In our case, the head of the World Wildlife Fund's marine program, Konstantin Zgurovsky, suggested that the cetaceans could have been stunned by seismic surveys or underwater acoustic systems of warships. According to the expert, there are also suggestions that animals are infected with worms or poisoned by pollutants entering the ocean, such as heavy metals.
Climate cycles could change the direction of movement of fish and other creatures that dolphins feed on. Dolphins, chasing prey, could swim close to the shore and land on land. This makes sense considering that sardines and other fish have been found washed ashore with dolphins in Peru.
Much more mysterious are cases when a whole group of animals washes up on the shore. One explanation scientists offer is that whales and dolphins, which hunt and migrate in small herds, are victims of their own social structure. If the leader or dominant animal is cast ashore due to illness or injury, the rest of the group may follow. Whales always help out a relative from their pod. If one of the whales wanders into shallow water by mistake, it immediately begins to send signals to its relatives, and they rush to help. Alas, the whales, instead of saving their comrade, get into trouble themselves.
Another version is that the herd swims too close to the shore and does not have time to return during low tide.
In some cases, marine animals commit mass “suicides” shortly after the active use of military sonars nearby. In 2000, in the Bahamas, for example, 17 animals of four different species (beaked whales, toothed whales, minke whales and spotted dolphins) were found on the shore in 36 hours - the day the sonar was used in these places and the next 24 hours.
Research conducted by the National Oceanic and Atmospheric Administration following this incident found that naval sonar devices were the most likely cause. Research data suggests that sonars had an impact on both the physical condition and behavior of marine animals.
Whales are excellent at navigating the ocean, so biologists say that they have a magnetic compass in their brains, thanks to which these sea creatures can navigate by the Earth's magnetic field. If a geomagnetic obstacle appears in front of whales, their internal compass becomes faulty and they begin to swim in the wrong direction. It is known that rescued whales often wash ashore again. Perhaps this is precisely explained by the breakdown of the compass - the whales returned to the water, but could not find their way.
There is also a theory of noise. This theory is the most popular today. Scientists claim that whales and dolphins are being killed by the deafening roar of submarines. Losing their hearing, whales lose their bearings and wash ashore. An examination of the bodies of the ejected animals suggested that the cause of suicide was decompression sickness. This malaise occurs when there is a sharp decrease in external pressure. Caisson disease is a disease of divers, pilots and workers who work in caissons (underwater work chambers).
A strong noise underwater frightens the whales, and they begin to rise up too quickly - there is a sharp decrease in external pressure. This provokes the occurrence of decompression sickness in whales. Echo sounders, radars, sonars, missiles, and submarines can scare whales. This version is supported by facts - there are several examples of whale strandings occurring during military exercises using sonars.
It also happens that animals are thrown ashore intentionally - for hunting. Black killer whales, for example, often attack pinnipeds such as seals or sea lions in the surf or close to the shore, where their victims change their mode of movement from swimming to walking and do so rather clumsily. While the animal is trying to get out of the water, the killer whale makes a dash and grabs the prey. After this, she can either wait for a suitable wave, or try to return to the ocean, wriggling her whole body.
Here is video evidence of one such hunt:
But 30 dolphins washed ashore:
Be that as it may, scientists have not yet come to a consensus.
