Dolphins are incredible mammals, about whose extraordinary intelligence and intelligence everyone has heard. There are many mysteries associated with them, and perhaps the most tragic of them is why these beautiful animals are thrown onto land? Let's look into this issue.
Causes of the phenomenon
Why the masters of the waves, dolphins, end up on land cannot be said for sure. Scientists and researchers can only build hypotheses based on the data and patterns obtained. Let's consider what can influence a dolphin so strongly that it leaves its habitat and ends up on land:
- Impaired echolocation function.
Echolocation is one of the business cards these animals. Unlike other mammals' common sense of smell, hearing and vision, dolphins rely on the ability to accurately determine distances to obstacles or future food.
To navigate in the water, the dolphin makes clicks and whistles. The emitted sound reaches an object within a certain radius, is reflected and returns back. The animal's hearing organs pick up reflected sound, which carries information about the shape, size and distance to the object.
One of the hypotheses why dolphins are thrown onto land is a distortion of the operation of such a mechanism. Due to poisoning, contamination of the water column, the operation of various devices, etc., a dolphin may receive incorrect information about surrounding objects and its location and become disoriented. Without understanding where it ended up, a mammal can throw itself onto land by accident.
- Attack by other animals.
An attack by a predator on a dolphin can also cause the animal to end its life on land. The conflict between killer whales, sharks and dolphins has long been known. Even one single shark can cause fear in a young individual, while a pair of killer whales can plunge a dolphin into horror. Trying to save my life by being exposed panic attack, often a dolphin finds itself first in shallow water, and then, with a breaking wave, on land in an unsuccessful attempt to save its life.
- Hunting.
In an attempt to get food by chasing small fish, squid or other aquatic life, dolphins often find themselves on the shallows, from where they are unable to get out on their own. Approaching powerful waves bring them straight to land.
- Old age and illness.
A number of factors can lead to impaired echolocation function and weakness. The most common of these are diseases to which dolphins are susceptible, old age or injury. Weakened animals are not always able to resist powerful currents, rushing to the shore, due to which sooner or later they may find themselves stranded again.
- Environmental degradation.
It's no secret that the water column is becoming more and more polluted every year, which is due to economic activity person. Pure water- the key to the life and health of many aquatic inhabitants. As a result of pollution, animal populations begin to rapidly decline, and the remaining individuals try to survive and begin the process of migration to cleaner regions. This behavior pattern applies to dolphins as follows:
- dolphins are also beginning to leave their native habitat in search of better conditions life;
- animals migrate after the source of food, because otherwise starvation is inevitable.
As a result, these unique mammals may again find themselves on the shallows, from where they have a direct path to the shore. This hypothesis is confirmed by the fact that often near ejected individuals they also find small fish, squid and other marine life, that is, direct representatives of the diet of dolphins.
- Natural balance.
Japanese scientists also suggested that in this way the process of self-regulation of the number of individuals occurs in dolphins. When the population size becomes too large, some individuals move to the shore to reduce it.
- A magnetic field.
There is also debate in scientific circles about the connection between the Earth’s magnetic field and the phenomenon under consideration. Some believe that waves have Negative influence on the ability of dolphins to navigate in space. As a result, dolphins end up in shallow water and subsequently on land.
Causes of mass suicide of dolphins
Cetaceans, which include dolphins, are prone to mass strandings on land. A mass stranding occurs when two or more dolphins become stranded within the same geographic region during the same tide cycle.
The causes of the phenomenon can be a variety of phenomena and factors, but they all have one thing in common: dolphins are extremely social mammals, where each individual worries about the safety of all others. On the one hand, this is an undeniable advantage of animals, because collectively it is easier for any living organism in nature to survive. However, this can also play a cruel joke for dolphins: throwing one individual ashore for one reason or another can lead to the death of an entire pod.
So, let's look at the main reasons for the mass stranding of dolphins on land:
- Noise underwater.
Submarines and other units operating underwater generate noise. The leader, who has lost his hearing as a result, loses the ability to echolocation and direct orientation in the water column. Throwing the leader onto land forces the entire pod of dolphins to follow the leader ashore.
- Opponents.
As already mentioned, dolphins have long had a bad relationship with sharks and killer whales. However, such a neighborhood can be the result not only of a single ejection of some stray individual, but of an entire flock. The more killer whales and sharks there are in the dolphins’ habitat, the more frequent and global strandings occur.
However, mass strandings of dolphins do not always occur due to their increased sociality. There are also a number of other possible reasons.
- Geographical position.
Cape Cod, Massachusetts, is known for its complex topography, a cocktail of narrow straits and hook-shaped peninsulas of land. Wellfleet Bay is especially notorious, in the area of which a huge number of mass strandings of dolphins are recorded.
Although Cape Cod has received the most publicity, scientists have found that it is no exception, and other places where dolphin strandings are regularly observed have similar topographical conditions.
It has also been noted that dolphin strandings often occur in regions with muddy shores and an abundance of shallows. It is believed that all these factors prevent the correct orientation of cetaceans in space.
- Ebbs and flows.
Several cases have been recorded of these cetaceans being thrown out during new and full moons, which have a direct impact on the ebb and flow of the tides. High level water during high tide, particularly during the full moon, allows dolphins to be closer to the coastline than usual. And the low tide often left whole schools of dolphins on the shallows along the entire coast. For comparison, in the area of the notorious Wellfleet, the difference in water levels during high and low tides can reach about 4 meters.
- Natural disasters.
Scientists also attribute the so-called “surge of water” or storm tide to the “merit” of the dolphins who found themselves on the shore. Stormy weather can significantly raise water surface levels and strong wind– generator of powerful waves. The result can be a whole combination:
- a school of dolphins is carried to the shallows, from where by strong waves they are carried to land;
- the flock may end up close to the shore, and when the water level after the storm returns to its original channel, the low tide situation will repeat.
Plus, natural disasters themselves disrupt the ability of dolphins to navigate in the water, changing the course of currents, creating additional noise, and so on.
What can you do if you find a dolphin on the shore?
A dolphin that finds itself on land can live for some time, but without outside help this period is very short. So what to do in similar situation?
First of all, you need to find out if the animal is alive. The easiest way to find out is by breathing. Dolphins do not breathe through their nose, but through a small hole located on the crown of their head, behind the frontal protrusion. The so-called blowhole opens and closes during inhalations and exhalations.
Once on land, the dolphin will not hold its breath. On average, he breathes once every 20 seconds, and the breathing process is accompanied by the opening of the blowhole. If the blowhole opens regularly, the animal is alive and you can move on to the next steps.
Keep in mind that if the animal has signs of decomposition, is not breathing, or has missing body parts, you should not touch it, since the dolphin’s body may well be a carrier of infection. Call the Ministry of Emergency Situations immediately.
If the dolphin shows signs of life, it must be placed on its stomach with its fins spread. You should also make sure that nothing interferes with his respiratory system.
Perhaps, most important rule to preserve the life of the dolphin - to prevent the animal from overheating and drying out. Need to water it sea water(at the same time, carefully ensure that water does not flow into the blowhole, otherwise the animal may suffocate). Afterwards, you can cover with a towel and sheet soaked in water and keep them moist at all times.
If you are waiting for the Ministry of Emergency Situations to arrive, then it will be enough to simply keep the animal in a stable condition.
If you decide to return the dolphin to the reservoir yourself (for example, it is not too far from deep water), then it is important to consider several points:
- Dolphins - pretty heavy mammals. The weight of dolphins found in the Russian Federation can range from 30 to 350 kilograms. Therefore, if you are not confident in your abilities, it is better to wait for help and provide the dolphin with a comfortable wait.
- It is best to deliver the dolphin to the water using a “stretcher” or by hand, but you should lift the animal onto the stretcher as carefully as possible, so as not to damage its delicate skin.
- If it is difficult to lift, and there is nowhere to wait for help, you can try to hold on. However, before this, you must place a tarpaulin, a sheet, etc. under the animal itself - in a word, you should not drag the dolphin along the sand.
Never drag a dolphin by its tail. This can cause irreparable damage to the spine and spinal cord animal.
It is not enough to simply leave a marine mammal in the water. He will need some time to restore blood circulation and motor activity. At this time, it must be supported, not allowing it to fall to the side. To speed up the process, you can massage the animal a little and very gently.
As soon as the dolphin comes to its senses, it will leave your hands and swim into the sea. At this point, the mission to save the animal can be considered over.
Dolphins are amazing creatures that have not yet been fully studied, in particular, there is still no accurate information about the reasons for their existence on land. For now, we can only hope that the answer will be found and this phenomenon can be avoided.
This year, the release of dolphins on the coast exceeded all statistical indicators by 10 (ten) times.
Dolphin strandings constantly occur from time to time.
However, this year (2013) the phenomenon exceeded all figures ever recorded by biologists. Ten times the average number of dolphins washed up on the American east coast.
Experts named the exact figure. Between July 1 and November 3, 2013, 753 bottlenose dolphins stranded on the American coast, from New York to Florida.
This was reported by ecologists from the National Oceanic and Atmospheric Administration (NOAA) to journalists from the American television channel Al Jazeera.
What is this phenomenon
In this geographic region, from New York to Florida, and in the specified time interval, from July to November, 74 dolphin deaths were recorded. This year this figure is an order of magnitude higher. The scale of what happened is simply amazing.
The sun warmed the sand. On a hot summer day, vacationers pay attention to the black fins that inexorably approach the shore, cutting the water surface. The outlines of the dolphins are already clearly visible. Drowsiness disappears from people's faces. Everyone watches the mammals with interest, expecting interesting moments. But the animals quickly, at full speed, rush to the shore. Interest on their faces gives way to anxiety. Meanwhile, heavy animal carcasses wash up on the sandy beach. After some time, a similar picture occurs a kilometer from this site. There, another group of animals washed ashore. And so it repeats day after day - sometimes more, sometimes less.
Most releases occur during the migration of dolphins in the summer months. If one individual is thrown ashore, the rest of the flock tries to help him and, often, shares his fate. Exhausted animals, with sunburn received on the shore, also very often repeat the path to the shore again, throwing themselves onto it.
What is this? How can this behavior of highly developed animals be explained?
Possible reasons for dolphin suicide
Since humanity does not know much about life in water, today there are different hypotheses and assumptions about the reasons underlying this phenomenon.
One of these assumptions is that this phenomenon is evidence of an impending global environmental catastrophe.
Of the marine animals, only cetaceans, to which dolphins belong, are marked by this phenomenon.
The orientation of dolphins in the water is carried out by a very precise location device. Its resolution is evidenced by the fact that dolphins easily find a pea in the pool. A failure in the operation of such a natural locator can lead to emissions. But such a “technical” hypothesis in no way explains the widespread nature of this phenomenon.
The hypothesis that tries to explain the mass character is based on the manifestation of a certain herd feeling. That is, he is trying to present the stranding of dolphins as a social phenomenon. But it’s not clear why the “instigator” himself decided to throw himself out? The splitting of the flock into small groups and their throwing ashore is also not explained.
Let's call it the medical version, which seems more realistic. The animals are struck by a certain disease, and they end their lives on the shore, without waiting to die in the water.
This version also has its “buts”. After rescuing some of them, the dolphins lived for many years in aquariums, were easy to train and were indistinguishable from their counterparts who were taken in the open sea.
Apparently, there is a combination of certain factors, both medical and social.
The main version is still “medical”
According to this version, the stranding occurs due to pneumonia and brain infection with a type of measles virus. Scientists from the US National Oceanic and Atmospheric Administration say that mammals are most likely dying due to morbillivirus, which belongs to the same group as the human measles virus.
Teri Rowles, a spokesman for the agency, said they cannot stop this epidemic due to the lack of a vaccine for the entire dolphin population. Department experts analyzed tissue from 33 stranded animals, and all but one of them were infected with morbillivirus. He noted that dolphins have very low resistance to this virus. As a rule, infection affects the skin, lymph nodes, lungs and brain of dolphins.
The possibility of transmission of the virus from dolphins to humans is practically excluded.
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.
And these days this phenomenon is not rare. 2002 - 55 whales washed ashore on Cape Cod Bay. Thanks to the efforts of American rescuers, 46 animals were saved. 2004 - in the area Canary archipelago 15 whales washed up on the shores of two islands. Only three of them were saved.
June 2005 - About 160 whales washed up on the coast of Australia. Rescuers, with the help of volunteers, did not allow the five-meter “fish” to die.
October 2005 - 70 whales died on the beaches of the island of Tasmania (Australia).
March 2007 - 12 whales washed ashore on one of the Galapagos Islands. Despite all the efforts of rescuers, seven animals died.
2012 - Cape Cod Peninsula only 177 common dolphins ran aground and 124 died.
Scientists are still searching for answers that will unlock this mystery.
There are many theories about why these smart animals end up in shallow waters and then wash up on shore. If one animal washes up on the shore, there may be several explanations for this.
Dolphins, whales, porpoises and seals beach themselves alone when they become disoriented or suffer from some disease, infection or injury.
Young animals just starting out independent life, can do this fatal mistake simply due to inexperience. Old animals may end up on the shore, dying due to natural reasons.
Unfortunately, human activity does not leave its mark on marine mammals, sometimes leading to the death of the animal or being thrown ashore.
Scientists suggest that cetaceans wash ashore en masse for the following reasons:
Unfortunately, the self-destruction of whales and dolphins remains a mystery. However, scientists continue to conduct research and, perhaps, they will soon find the answer to this painful question for many.
In early February 2017, near Cape Fearwell in New Zealand, about 400 pilot dolphins again washed up in shallow waters. The press reported that about 300 dolphins were already dead. Volunteers and ordinary residents tried to save them, but only a small part of the mammals survived.
This is a real disaster. Cetaceans have been stranded here before. The same incident happened in 1918 on the local islands. Then about 1000 cetaceans rushed to land. Another mass dolphin suicide occurred in 1985, when 450 pilot whales washed up on a beach in Auckland. Why do dolphins strand on land? What force pushes them towards the shore? There are several well-known hypotheses that are expressed by conservationists.
Dolphin - guardian of planet earth
As you know, dolphins are conscious mammals that have their own language, as well as a sound alarm system. The language of dolphins is divided into 2 groups: the language of sounds and the language of gestures.
- The language of sounds includes: ultrasound and sound impulses. First of all, it is a whistle. As well as clicking, squeaking, chirping, popping, squealing and screaming. In 2006-2007, Americans conducted research - they came to the conclusion that dolphins have 32 types of whistles, each whistle means a specific call, or signal.
- Dolphin body language: jumping, pronounced poses, signs, slaps in the water, and so on. Despite many experiments, we have not yet been able to decipher the language of dolphins; we can only guess what they are trying to tell us. In addition, scientists from the state of Florida came to the conclusion that each dolphin is given a name at birth, which is indicated by a certain whistle.
Employees of the Karadag Nature Reserve recorded a conversation between two dolphins. It was discovered that while one speaks a whole sentence consisting of impulses, the other listens to it, and vice versa. It's like a conversation between people. Professor Ryabov stated: “The language of dolphins contains all the features that correspond human speech, and this means that dolphins are intelligent.”
Pulse graph
I would also like to note the relationship between a dolphin and a human: they treat us as friends, brothers in mind. It is no coincidence that dolphin therapy has long been used to improve people’s health. Dolphin therapy, that is, contact with a dolphin, has a particularly good effect on sick children.
Physiotherapists believe that communication with dolphins contributes to both the physical and spiritual health of children. This treatment applies to children with cerebral palsy, developmental delays, and autism.
For adults, such therapy helps fight stress, chronic syndrome. fatigue, nervous system disorders.
And the stranger and more incomprehensible are the actions of some European countries, and Japan, where the attitude towards dolphins is simply barbaric.
Shocking in its cruelty mass kill dolphins off the coast of the Faroe Islands, when these rare animals are killed in the thousands, hiding behind their “traditions.” This tradition begins in the 10th century and continues every year. In this case, there are teenagers, children, pregnant women - in general, all residents of the Faroe Islands. The water turns red, and only the cries of dolphins can be heard...
Firstly, a dolphin is not a simple animal, and the abuse of them cannot but leave a mark on new generations, thereby shaping children's minds. And these killings of dolphins occur in civilized countries! Even in the jungle, the struggle for survival occurs according to the rules established by nature, but man always deliberately violates these rules. Destroying animals thoughtlessly, for the sake of a whim, a person comes closer and closer to the edge of the abyss.
Mass dolphin suicides
Why do dolphins and cetaceans become stranded? Why do they commit mass “suicides”? There may be several answers here, and it is up to you to decide which one is correct.
- Many scientists believe that the deliberate death of dolphins is a consequence of health problems. The ocean is becoming polluted, and more and more every year. But there have been suicides of whales and dolphins before, even in the Middle Ages. By the way, some scientists say that maybe we shouldn’t save mammals that end up on the shore?
- Professor Belkovich, who works at the Russian Research Institute of Oceanology, believes that there is an instinct for mutual assistance here: when trouble happens to one dolphin, the entire group, hearing the SOS signal, rushes to the rescue of one - and dies. His guess: the dolphin is sick, and the sick one wants to get support from the pod. And if he finds himself stranded, then the whole flock rushes after him.
- Many species of cetaceans are very sensitive to the work of sonar. According to Professor Belkovich, dolphins are simply destroyed by sonar, they lose acoustic control, and as a result, they lose orientation and stop perceiving signals. IN familiar surroundings These mammals, with the help of signals, are able to distinguish what is in front of them: earth, stone, food. If they lose echo control, it's a disaster for them. In 2000, American naval exercises took place near the Bahamas; at the same time, there was a case of dolphin deaths. Studies were carried out on the bodies of the dead dolphins, as a result of which it was concluded that they died from decompression sickness. Decompression sickness is called a disease of pilots and divers. This disease occurs when there is a sharp decrease in environmental pressure.
- Nowadays there are devices that jam and block the operation of electronic equipment; perhaps the latest case in New Zealand is a consequence of this?
- Cetaceans are known to live in the same environment for millions of years. People populate the shores, invading and destroying the usual habitat of animals. Dolphins wash ashore in areas where many people live. People spend their time on beaches and coastlines as their lifestyle has changed. In other words, there are too many people on the planet.
But these are all just assumptions; no one yet knows the exact reason for the dolphins’ suicide. The video tells the story of how black dolphins washed ashore en masse in New Zealand.
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.
What does a Maui dolphin look like?
Maui's dolphins are a sub-species of Hector's dolphins, which are more abundant on the South Island. Although both Maui and Hector's dolphins look very similar to each other, they are genetically different from each other. On the other hand, the Maui and Hector deltas are very different from other dolphin species as they are the smallest dolphins in the world. They are usually 3-7 meters in length, with females being the largest. They are also the only dolphins with a rounded black dorsal fin and a black tail, flippers and eyespots.
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 they undertake to name the reasons for only half of such incidents, and these reasons are very different.
The best way to identify a Maui dolphin is simply by seeing this round, black dolphin from the shores of the North Island. Typically swimming in pods, Maui's deltas are found close to shore in water less than 20 meters deep. However, they are known to be located further from the coast.
Dolphins are now known to use the mouths of Manukau and Kaipara, which are huge harbors on the west coast of the Auckland region. Maui's dolphins don't tend to stay in one place for long, as they have been found to travel 80 km over the course of three weeks. However, they tend to use about 30 km of coastline.
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.
Why are Maui's dolphin numbers declining?
Although Maui deltas once inhabited the waters around them, sightings in this area have become extremely rare. There are natural and human threats that impact Maui's dolphin population. While we can't control the natural factors of predation from sharks and oracs, extreme weather conditions and disease, we can control the human-caused threats that seem obvious when you see the many photos released of dolphins caught in fishing nets.
Because the coastal human and dolphin distributions in Maui all occur in coastal settings in the same environment, this has a catastrophic effect on the dolphins - affecting the dolphins' struggles due to their slow reproductive cycle.
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.
Human threats to Maui's dolphins include. Net fishing, trawling and drift netting, which can lead to entanglement and drowning of dolphins.
- Boats hit dolphins.
- Marine debris gets in or causes dolphins to become entangled.
- Offshore mining and construction such as seismic exploration.
- General pollution.
Is there any hope for the survival of the Maui dolphin?
This is still a question that scientists are trying to answer, but it can only be answered by observing the rest of Maui's dolphins in the wild. Check out the How Can You Help? section. Below. From the data obtained so far, it was clear that at least two South Island Hector's dolphins were among the Maui pods, suggesting interbreeding could result in an increase in Maui's genetic diversity. This could be promising in the future.
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.
Already on the west coast of the North Island, a marine mammal sanctuary has been established as a measure to protect dolphins by enforcing stricter fishing regulations. If you see a Maui dolphin, that's great! Mass twisting on this scale is almost unprecedented.
About 300 of them have already died. There haven't been enough large-scale surveys to know exactly how many pilot whales are swimming in the deep waters around New Zealand. But scientists know that the van-sized creatures tend to live in matriarchal family groups of 20 people, up to 100 people.
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 leader maritime program WWF Konstantin Zgurovsky suggested that 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.
"It's just terrible, it will certainly make a dent in New Zealand's flying whale population," says Liz Slooten, a professor at the University of Otago in New Zealand who studies marine mammal biology and conservation.
Pathologists are conducting post-mortem examinations of the whales to try to understand what happened to do so much washing on the shore. Because right now the reason is still a mystery. Sometimes extreme weather or unusual topography of the ocean floor can force whales to move into water that is too shallow to escape.
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.
Right now, the reason is still a mystery. Marine mammals were also associated with naval intelligence oil and gas project, which uses air guns to blast the ocean floor with sound waves. They can directly damage the delicate hearing that marine animals such as whales and dolphins use to navigate, or panic them too quickly, or swim in shallow waters.
With whale pilots, an injury to just one of them can cause problems for the entire pod. “Typically in this group there are one or two people who are experiencing some kind of problem, either sick or dying or sometimes having problems with the birth,” Sloten says. Social organization The whale pilots are so strong that when something like this happens, the rest of the group won't leave. That's why there are usually several dozen, sometimes a couple of hundred whales.
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.
But she adds: "It's really unusual, it's a large number of whales." They are rarer than kiwi and are threatened by commercial and recreational fishing. There are fewer than 50 Maui dolphins left in the world. Entanglement in fishing nets is the number one threat. Fishing has caused a significant population decline. The current population size of about 10% for Maui and 30% for Hector's dolphin protection is not enough to help restore Maui's or Hector's dolphins.
- New Zealand dolphins are found only in New Zealand.
- Hector's dolphin is a subspecies of the South Island.
- The Maui dolphin is a subspecies of the North Island.
- Both are endangered.
- The Maui dolphin is endangered.
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.
The other dolphin does not have a rounded dorsal fin. The fins of most dolphins are more triangle-shaped, like a shark's fin. Other dolphins are about human size, about 2 meters long or more. Today the population is fragmented into small local populations.
This is reflected in their complex behavior and social system. Smaller groups of 2-8 usually consist of a few males or several males and their calves. Their social system is usually described as "fission-fusion". In other words, if a group of 4 and a group of 5 meet, they do not necessarily split back into their original groups, but may go into new and different groups when they go their separate ways.
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.
We know that from studying the stomach contents of dolphins that have been found dead on beaches or caught in fishing nets. A woman can have her first calf when she is 7 to 9 years old, and will have one calf every 2 to 3 years after that. This means that the overall population growth rate is about 2%. This makes them very vulnerable to human influence.
Compared to other conservation problems, this can be easily solved. The biggest obstacle is the lack of political will to make this happen. Dolphin protection is still insufficient to provide effective protection. In the map above, dolphin sightings are shown as blue dots and red dots. The gray area is a protected area where gillnets are not permitted.
Whales are excellent at navigating the ocean, so biologists say they have a magnetic compass in their brains, which makes them Marine life 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.
Iron sand seabed mining vacuum on seabed, filters out minerals and then discharges the dirt back into the ocean. The small town on the northern coast is called Mtunzini. This is a very hot city with warm water. A right whale and her baby were discovered today. Isn't it so far from home?
New Zealand has one of the highest twist rates in the world. On average there are about 300 dolphins and whales every year. Most twisters are individual animals, but mass twisters are common and can involve hundreds of animals at a time.
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).
Wanderers are complex events, and there are many reasons why dolphins and whales may spin. In most cases, the exact cause is unknown, but any of the following factors or a combination of them may be the cause. Older whales may have difficulty keeping up with their pod or resisting heavy swells or coastal currents. The effects of such a disease leave them weak and disoriented or with impaired echolocation, and they hide. Natural toxins can poison whales. Because they are at the top of their respective food chains, contaminants tend to bioaccumulate in their fat. Food shortages caused by overfishing could lead to depletion of whale stocks. Individual dependent calves and the elderly may also be malnourished. Unfortunately, many daggers have been found with large amounts of debris or plastic in their intestines. Ingestion of these materials can lead to illness and malnutrition. Kelvings will often seek refuge to give birth to their children. If they come too close to the shore, they may spin. In particular, whales that have problems giving birth are more likely to. Whales that avoid empty snags or become caught in vessels can sustain serious injuries such as broken teeth and jaws, deep lacerations, pleural dislocations or fractures, spinal or muscle damage, or severed fins or flukes. Underwater explosions caused by sonar, seismic testing or underwater marine earthquakes can have devastating effects on whales. These loud explosions can damage their hearing and affect their ability to communicate, hunt and move around. They may be lifted up by a wave and washed onto the beach, or left high and dry by the receding tide. They may also end up too close to shore to avoid predators such as Orca. Be careful with the racks, sandy beaches may not reflect echolocation signals back to the whale, causing them to believe they are in deeper water. Combined with a fast falling tide, the whales can stay high and dry. Some whales may use geomagnetic contours to navigate, and where they cross a shore or outcrop, this may cause the whale to follow the contour line to shore. Unfamiliar coastal configurations or unusual weather conditions, especially electrical storms, may also result to the appearance of whales through a navigation error.
- Due to unfortunate strength, these animals can spin.
- As a rule, they are in poor condition.
- Whales can suffer from a number of diseases.
- It could be a temporary misfortune or something more serious.
- This may cause them to curl.
- When chasing prey, whales may accidentally dance themselves.
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 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.