From the order of cetaceans, related to baleen whales. The largest whale, the largest modern animal, and also probably the largest of all animals that have ever lived on Earth. Its length reaches 33 meters, and its mass can significantly exceed 150 tons.

Appearance and structure

The physique is proportional, the body is well streamlined. The head is convex laterally, but blunted in front. The breathing hole (breathing hole) is surrounded in front and on the sides by a roller, turning into a crest, which, gradually lowering, ends at the end of the snout. The eyes are small, set slightly behind and above the corner of the mouth. The length of the eye slit is 9–10 cm. The lower jaw is strongly curved to the sides; when the mouth is closed, the snout protrudes 15–30 cm forward. There are several dozen short (15 mm) hairs on the anterior part of the head and lower jaw, the number of which varies.

The miniature dorsal fin is set far back, its height is only about 30 cm and can have a variety of shapes (with a rounded end, triangular, etc.). The pectoral fins are narrow, pointed and somewhat shortened (1/7 - 1/8 of body length). The width of the caudal fin with a small notch in the middle is equal to 1/4 of the body length. The head is wide, U-shaped from above, with margins convex to the side. There are 70-114 longitudinal skin "stripes" on the belly, 80 on average. The depth of the thoracic-abdominal stripes is up to 2 cm, the width is about 5-6 cm. The longest ones reach almost to the navel.

The body of the blue whale is dark gray, with a bluish tinge, mottled with light gray spots and a marbled pattern. The head, lower jaw and chin are one-colored. There are more spots in the posterior half of the body and on the belly than in the anterior and on the back. The belly may be yellow or mustard. The mass of the heart is more than half a ton. The diameter of the aorta reaches the diameter of a small bucket, and the lungs can hold up to 14 m3 of air.

Behavior and lifestyle

In general, the blue whale tends to be more alone than all other cetaceans. The blue whale does not form herds, it is predominantly a solitary animal, although sometimes blue whales form small groups consisting of 2-3 heads. Only in places with particularly abundant food can they form larger aggregations, dividing into smaller groups. In such groups, the whales are scattered, although the total number of such accumulations of blue whales reaches 50-60 heads.

The blue whale, swimming near the surface of the water, is nowhere near as agile as some other large cetaceans. In general, its movements are slower and, according to scientists, more clumsy than other minke whales. The activity of blue whales at night is poorly studied. Most likely, he leads a diurnal lifestyle - this is evidenced, for example, by the fact that whales off the coast of California almost stop moving at night.

The blue whale dives quite deep, especially if it is very frightened or injured. Data obtained by whalers using special devices mounted on a harpoon showed that a harpooned blue whale can dive up to 500 m, and according to American data, a whale can dive even up to 540 m. Normal dives of a feeding whale rarely exceed 200 m, and more often no deeper than 100 m. Such dives last from 5 to 20 minutes. A grazing whale dives rather slowly - it takes about 8 minutes to dive to 140 m and then resurface. After surfacing, the whale's breathing quickens up to 5-12 times per minute, and each time a fountain appears. Rapid breathing continues for 2-10 minutes, after which the whale dives again. The vomit, pursued by whalers, is under water much longer than usual, up to 50 minutes.

After a long and deep dive, the blue whale makes a series of 6-15 short dives and shallow dives. For each such dive, it takes him 6-7 seconds, for a shallow dive - 15-40 seconds. During this time, the whale manages to swim 40-50 m, not deep under the surface of the water. The highest dives in the series are the first after the rise from the depth and the last (before diving). In the first case, the whale, slightly bending the body, first shows the very top of the head with a blowhole, then the back, dorsal fin, and finally the caudal peduncle. Going to the depths, the blue whale strongly bends the body, tilting its head down, so that the highest point is the part of the back with a fin, which are shown when the head and front of the back are already deep under water. Then the “arc” of the back becomes lower and lower, and the whale hides without showing its tail. The tail fin of a diving blue whale rarely shows - in about 15% of diving cases. Blue whale sightings off the southern coast of California have shown that they spend 94% of their time underwater.

At a short distance, a blue whale can swim at speeds up to 37 km / h, and in exceptional cases even 48 km / h, but it cannot maintain such a speed for a long time, since this is too much stress on the body. At this speed, the whale develops power up to 500 horsepower. Grazing vomit moves slowly, 2-6 km / h, during migrations faster - even up to 33 km / h.

The blue whale breathes 1-4 times per minute in a calm state. Studies in the 1970s showed that the respiratory rate of blue whales (and minke whales in general) is highly dependent on the size and age of the whale. Young whales breathe much more often than adults - for example, when surfacing after a deep dive, the frequency of respiratory acts (inhale-exhale) in a blue whale 18 m long was 5-10 in 2 minutes, while in an adult 22.5-meter vomit - 7 -11 times in 12.5 minutes. Respiration rates for whales of this size that did not dive were 2-4 and 0.7-2 times per minute, respectively. An adult blue whale pursued by whalers breathed (gave a fountain) 3-6 times per minute.

Nutrition

The largest animal on earth consumes about 1 million calories a day. This is approximately 1 ton of krill, which is the main diet of the blue whale. In general, the blue whale is a typical plankton-eater: it feeds on crustaceans in the upper water column, plunging under water for 10-15 minutes. The crustaceans that it feeds on are concentrated in special zones, which are called feeding fields. In such places, you can meet several whales at once, although they usually do not gather in groups of more than 3 individuals.

Fish, if it plays any role in the diet of the blue whale, is very insignificant. Soviet sources indicated that the blue whale does not eat fish at all, other sources more specifically indicate that they still eat fish. Most likely, ingestion of fish and other small marine animals occurs by chance, when eating masses of krill. It is also possible that the eating of small schooling fish and small squid observed in the western Pacific Ocean is caused by the absence of large accumulations of planktonic crustaceans. In addition to a small number of small fish, small non-krill crustaceans were found in the stomach of the blue whale.

The blue whale feeds in the same way as the rest of the minke whales. A grazing whale swims slowly, opening its mouth and taking in water with a mass of small crustaceans. The stripes on the throat allow the whale's mouth to stretch very much, and the movable articulation of the bones of the lower jaw also greatly contributes to this. Having scooped up water with crustaceans, the whale closes its mouth and squeezes the water back through the whalebone with its tongue. In this case, the plankton settles on the mustache fringe and is then swallowed.

The huge lower jaw, filled with water and food, is so heavy that it is sometimes difficult for a blue whale to move it to close its mouth. Measurements of a 150-ton blue whale 29 m long showed that its mouth could hold 32.6 m³ of water. Therefore, often a blue whale, having gathered food in its mouth, turns over on its side or even on its back, and then the mouth slams itself shut under the influence of gravity. Due to its huge size, the blue whale is forced to consume a very large amount of food - according to various sources, it eats from 3.6 to 6-8 tons of krill per day, and it is estimated that the number of individual crustaceans in this mass reaches 40 million. In general , a blue whale needs to feed about 3-4% of its body weight per day. The aforementioned whale, with a mouth volume of 32.6 m³, could capture over 60 kg of crustaceans at a time at a normal density of krill in the ocean. A blue whale's stuffed stomach can hold up to a ton of food.

Whale songs

Leading a solitary life of whales, whales have developed their own way of communication, with which they communicate with each other over vast distances up to 1600 km. These are the famous songs of whales, the volume of which reaches 188 decibels. The meaning of these songs is not fully understood, but scientists have noticed that whales "sing" during the breeding season, so it is possible that singing is somehow connected with the family functions of animals. These songs last up to half an hour.

At first, it was believed that only males sang, but there is evidence that female blue whales also sing for their babies. The sound-reproducing system in animals is located in the front of the head and serves as a lens that captures and reproduces sounds. Since whales are practically blind and have no sense of smell, sound is the only means of communication with other individuals, and the only way to contact the outside world. Therefore, whales are constantly busy analyzing the surrounding sounds.

Oceanographers have collected and analyzed thousands of recordings of blue whale "songs" that have been documented by various instruments over the past 45 years. It turned out that slowly but steadily, by fractions of a hertz per year, the tonal frequency of sound decreases. This happens regardless of the ocean where the animals live. But, for example, in most of the surveyed populations of whales living near California, the sound frequency of songs has decreased by 31% since 1965.

Among the possible reasons for this phenomenon, which experts consider in an article published in Endangered Species Research, is a reaction to a change in the composition of the water in the ocean, as well as simply the desire of young whales to imitate the timbre of older ones, in which it decreases with age.

The most plausible and at the same time the most unfunny option is that due to the fatal decrease in the number of blue whales, they now need to send their “messages” more far, and low-frequency sounds, as you know, travel further in the ocean.

reproduction

The peak of mating in blue whales occurs in winter: in January - in the northern hemisphere and in July - in the southern hemisphere. The length of the body of newborns is from 6 to 8.8 m, more often 7-8 m, with a weight of 2-3 tons. A strong variation in the size of embryos obtained at the same time indicates an extension of the mating period for almost the entire year. An analysis of the size of embryos in Antarctic catches showed an average increase in their body by 35 cm in November, by 56 cm in December, by 72 cm in January, by 92 cm in February, and by 79 cm in March (Tomilin, 1957). Apparently, the growth rate of the embryos gradually increases, but by the end of uterine life, it slows down somewhat.

Pregnancy lasts a little less than a year (about 11 months). Usually one cub is born, cases of multiple pregnancies are rare. According to the International Whaling Statistics (ISS), among 12,106 Antarctic embryos, there were 77 cases of twins, five cases of triplets, one find with five and one with seven embryos. Of the twin embryos, as a rule, only one develops to the end, the rest die and are resorbed. During the 7-month lactation period, the cub, eating very fatty milk (34-50% fat), grows up to 16 m and weighs 23 tons, and at the age of 19 months reaches 20 m and weighs 45-50 tons; medium individuals (23.7-24 m) weigh 80-85 tons, and large ones (30 m) - 150-160 tons (Wheeler a. Mackintosh, 1929; Krogh, 1934; Ruud, 1956). Sexual maturity occurs at 4-5 years, as evidenced by 8-10 layers in the ear plugs, which determine the age. Females at this time reach a length of 23 m. They reach full growth and physical maturity at a body length of 26-27 m, which probably happens at 14-15 years.

The average daily weight gain of sucklings, according to zootechnical calculations (Tomilin, 1946), reaches 81.3 kg with a daily consumption of 90 kg of milk. Sexual maturity occurs at 4-5 years of age, when 8-10 layers appear in the ear plugs by which age is determined (Nishiwaki, 1957); at this time, the length of the southern females reaches an average of 2-3.78 m, the northern ones - 23 m, and the average weight of the testes of males - 10 kg (Ruud, 1950, 1957). Usually females breed every two years. A strong variation in the percentage of pregnant females among mature ones (from 20 to 61%: Laurie, 1937; Ottestad a. Ruud, 1936) depends on the accuracy of registration of embryos at whaling bases and on the number of individuals studied (large deviations are possible with smaller material).

Females reach physical maturity when 11-12 scars of the corpus luteum accumulate in the ovaries; this happens at 14-15 years of age, and possibly at an even older age, with an average body length of 26.2 m (Laurie, 1937), 26.5 m (Brinkmann, 1948) and 26.67 m (Peters, 1939 ). The minimum size of physically mature Antarctic females was set at 24.7 m, and for males - 22.3 m. . Only 25 scars were found in the oldest female in the North Pacific (Omura, 1955).

population

The initial number of blue whales, before the start of their intensive fishing, was estimated at 215 thousand heads. According to other sources, it could be even more, up to 350 thousand. The first bans on blue whale fishing in the Northern Hemisphere date back to 1939; they affected only certain areas. The fishery was completely banned in 1966, but the ban on fishing, however, did not immediately affect the blue pygmy whales, which continued to be harvested as early as the 1966-1967 season.

The current population of blue whales is difficult to estimate. The reason, perhaps, is that blue whales have not been studied very actively for decades - for example, according to authoritative sources in 1984, the International Whaling Commission has practically not counted the number of these whales since the mid-1970s. In 1984, it was reported that no more than 1900 blue whales lived in the Northern Hemisphere, and about 10 thousand in the Southern Hemisphere, half of which were dwarf subspecies.

According to some data, there are now between 1,300 and 2,000 blue whales in the entire world ocean, but in this case, the number of these whales is even lower than 40 years ago, despite the complete absence of fishing. Other sources give more optimistic figures: 5-10 thousand vomits in the Southern Hemisphere and 3-4 thousand in the Northern Hemisphere. The question of the quantitative distribution of the world population of blue whales in individual areas is also not fully clarified.

A number of sources indicate that from 400 to 1400 blue whales live in the Southern Hemisphere, about 1480 in the North Pacific Ocean, while the number of blue whales in the rest of the Northern Hemisphere is unknown. Regarding the Southern Hemisphere (more precisely, the Southern Ocean), other figures are also indicated: 1700 heads with a 95% probability that this number is between the two extreme values ​​\u200b\u200bof 860 and 2900. At the same time, according to the International Whaling Commission, 6 herds live in the Southern Hemisphere blue whales. Whales of the southern subspecies, which became the main object of attention of whalers in the twentieth century, according to estimates in 2007, only 3% of the population of 1914 remain.

The growth of the blue whale population is slow, but in a number of places, for example, in areas near Iceland, the increase after the ban on fishing reached 5% per year. American scientists who conducted a detailed study of the population of cetaceans off the Pacific coast of the United States noted that the number of blue whales in these areas tended to increase throughout the 1980s. However, the same study concludes that there is no data on population growth in the Pacific Ocean as a whole. There are legitimate fears that the blue whale population may never recover to its original abundance.

Whales are very intelligent animals. Their incredible intelligence and friendly nature have made whales very popular and interesting animals for science. Scientists generally believe that the brain of whales is more similar in its capabilities to the human than the brain of any other animal.

Some features of the structure of whales are very interested in physicians. So whales do not have brain hemorrhages, due to the fact that in their heart there is a special shunt that connects two large arteries, which provides reliable protection against blockage of blood vessels, and as a result, from heart attacks.

The whale eye is also of interest to scientists. Firstly, because in it the size allows you to see what cannot be seen in the eye of a person or other animal. Secondly, the blue whale can dive underwater to great depths, and the structure of its eye is such that it can withstand enormous pressures. Having learned this secret, a person will help patients with glaucoma associated with impaired intraocular pressure.

Blue whale (blue whale) - the largest marine mammal of the cetacean order. The blue whale is the absolute record holder among the largest animals in the world, and is also considered the largest animal that has ever existed on Earth. For many millions of years of evolution, nature has not been able to create an animal larger than the blue whale.
In length, the blue whale can reach more than 33 meters, the average weight is about 130 tons, but there are individuals reaching 190 tons; as a rule, in baleen whales, females are always larger than males.

The main features of the blue whale

1. The volume of the lungs is 2.5% of the weight of the whale and is close to 3.5 thousand liters.
2. The heart of a blue whale is truly huge and reaches 700-1000 kg. The heart pumps 10 tons of blood through the body, the largest artery of the blue whale is the dorsal artery and its diameter is 40 - 45 cm. The heart rate is 5 - 10 beats per minute, can reach 20 beats.
3. The weight of subcutaneous fat in the blue whale is 27% of the total weight, more than 30 tons in large individuals, the thickness of the fat layer is 30 cm.
4. The tongue of the blue whale weighs from 3-4 tons.
5. The liver weighs 1 ton.
6. The stomach of a blue whale can hold 2 tons of food.
7. The whale's mouth area is approximately 25 square meters, but the pharynx is very narrow, like all baleen whales, about 10 cm in diameter.
8. Of the five senses, three are very poorly developed (smell, sight, taste), but hearing and touch in blue whales are at their best.

Habitats of blue whales

As befits the largest creature on the planet, the blue whale's habitat is incredibly wide, these giants can be found from the Arctic to the Antarctic. Still, cold waters remain preferable, but the southern limits are not deprived of the attention of baleen whales. The only place where the fin of a blue whale does not wave is the equator, too warm for a giant clad in armor of subcutaneous fat.
Appearance
As befits a marine inhabitant, the body of a blue whale is of a streamlined proportional shape, the head is approximately 1/3 of the body length and has a U-shape. From the lower jaw and along the belly, the whales have skin stripes, which firstly help the whale's throat to stretch while swallowing water, and also affects the hydrodynamic capabilities of the whale body. The dorsal fin of the blue whale is the smallest of all representatives of baleen whales, it is shifted far back and its size does not exceed 30-35 cm. The tail fin reaches a width of about 7.5 m. The lateral fins are narrowed and rather long, about 1/7 whale body length. The skin of the blue whale is dark gray with a blue tint.

Whalebone

Whalebone is a unique filter that nature has replaced the teeth of baleen whales with. The blue whale feeds on plankton, small crustaceans and molluscs. The whalebone works on the principle of a filter, it does not allow too large prey contained in huge volumes of water absorbed by the whale to get into the mouth. After filtering, the blue whale uses its tongue to push the water back out and the baleen comes into play again, this time preventing food from escaping through the plates back into the ocean. The whalebone of a blue whale is absolutely black in color, consists of individual plates, the length of which ranges from 90 to 100 cm, the width is about 50 cm. The number of plates, depending on the size of the owner, can be from 550 to 800 pieces.
Before the invention of polymers, whalebone was widely used in the production of clothing, in particular women's corsets, which became one of the reasons for the mass extermination of whales.

Blue whale behavior

Blue whales are social animals that live in groups of 3 to 5 individuals. The small number of groups is associated with the large size of the blue giants, since. it is more difficult for a large group of whales to obtain food in sufficient quantities. An adult whale needs about 1.5 tons of food per day. During the feeding period, the blue whale can dive to a depth of up to 200 meters for 10 to 20 minutes. The speed of movement during feeding does not exceed 10 - 12 km / h, but the blue whale can, if necessary, reach speeds of up to 50 km / h.
Reproduction of blue whales is not a fast process, the female gives birth once every two years, pregnancy lasts 10 - 12 months. The weight of a newborn blue whale is 2 - 3 tons, and the length is 6 - 10 meters. Feeding lasts 7 months, during which the cub grows up to 16m in length and reaches a mass of 20 tons. At the age of 1.5 years, the weight of the whale reaches 50 tons. Puberty in blue whales occurs at the age of 4-5 years.

Blue whale in the photo and video below.

“Sea monster” is the Greek word κῆτος (whale), applied to all cetaceans except porpoises and dolphins. But, answering the question "how much does a whale weigh", one cannot do without dolphins. In this family, there is a monster heavier than many real whales - a killer whale.

Whale weight by species

Whales deservedly bear the title of the heaviest animals, both terrestrial and aquatic.. The cetacean order consists of 3 suborders, one of which (ancient whales) has already disappeared from the face of the Earth. The other two suborders are toothed and baleen whales, which are distinguished by the structure of the mouth apparatus and the type of food closely associated with it. The oral cavity of toothed whales is equipped, as it is logical to assume, with teeth, which allows them to hunt big fish and squid.

On average, toothed whales are inferior in size to representatives of the baleen suborder, but among these carnivores there are amazing heavyweights:

• sperm whale - up to 70 tons;
• northern floating fish - 11–15 tons;
• narwhal - females up to 0.9 tons, males at least 2-3 tons (where a third of the weight is fat);
• white whale (beluga whale) - 2 tons;
• pygmy sperm whale - from 0.3 to 0.4 tons.

Important! Porpoises stand somewhat apart: although they are included in the suborder of toothed whales, in a strict classification they do not belong to whales, but to cetaceans. Porpoises weigh about 120 kg.

Now let's look at dolphins, which pedantic ketologists also deny the right to be called true whales, allowing them to be called cetaceans in the group of toothed whales (!).

Whale weight at birth

When born, a blue whale calf weighs 2–3 tons with a body length of 6–9 meters. Every day, due to the exceptional fat content of mother's milk (40–50%), he becomes heavier by 50 kg, drinking more than 90 liters of a valuable product per day. The cub does not come off the mother's breast for 7 months, gaining 23 tons by this age.

Important! By the time of the transition to self-feeding, the young whale grows up to 16 m, and by its one and a half years, the 20-meter "baby" already weighs 45-50 tons. He will approach adult weight and height no earlier than 4.5 years, when he himself becomes able to reproduce offspring.

Only a little behind the newborn blue whale is the baby fin whale, which at birth weighs 1.8 tons and is 6.5 meters long. The female feeds him with milk for six months, until the child doubles its height..

Weight: up to 150,000 kg
Length: up to 33 meters, depending on location (in Antarctica, blue whales are the largest)
Lifespan: unknown, but they are able to give offspring at 5-15 years
Nutrition: mostly krill meat
Behavior: born and mate in winter
Blue whales are distributed throughout the world. Those living in the Northern Hemisphere tend to be smaller in size than those living in the Southern Hemisphere

In the North Atlantic and North Pacific, they can grow up to 27 m, but, in the Antarctic, they can reach up to 33 m and can weigh over 150,000 kg. Like other baleen whales, female blue whales are slightly larger than males in weight and size.
Blue whales have a long body and a relatively thin shape, a wide, flat mouth when viewed from above, a small dorsal fin, and a mottled gray coloration that turns light blue (hence the tout, "blue" whale) when viewed through the water.
The main food of blue whales is krill (euphausiidae).
In the North Atlantic, blue whales feed on two main euphausian species (Thysanoessa inermis and Meganyctiphanes norvegica). In addition, T. raschii has been identified as an important food source for blue whales in the Gulf of St. Lawrence.
In the North Pacific, blue whales prey mainly on Euphausia pacifica and secondarily on Thysanoessa spinifera.
While their other prey species, including fish and crustaceans, may be part of the blue whale's diet, they probably don't contribute much.
Scientists have yet to reveal many details regarding the life history of the blue whale.
The gestation period is approximately 10-12 months, the blue whale cubs feed on mother's milk for approximately 6-7 months. Active reproductive activity, including birth and mating, takes place during the winter. Weaning probably occurs during the period of migration to summer habitats. The average interval between births is probably two to three years. The age of puberty is considered to be 5-15 years.

Habitat

Blue whales are found throughout the world, from subpolar to subtropical latitudes. The movement of whales in the spring determines the zone of zooplankton in the summer. Although blue whales are found in coastal waters, they are believed to live much farther from the coast than other whales.
Population distribution
Blue whales are found in all oceans and are divided into ocean basin groups in the North Atlantic, North Pacific, and Southern Hemisphere.
They migrate seasonally between summer and winter, but some evidence suggests that some individuals remain in certain areas year-round. The amount of knowledge about their habitat and migration routes is not sufficient.
In the North Atlantic Ocean, the blue whale lives from the subtropics to the Greenland Sea. Blue whales are most commonly sighted in eastern Canadian waters near the Gulf of St. Lawrence, where they are present for much of the year.
In the North Pacific, blue whales range from Kamchatka to southern Japan and from Alaska to Costa Rica in the east. They are found mainly south of the Aleutian Islands and the Bering Sea.

Blue whales in the North Pacific probably exist in two subgroups:
Northeast Pacific
Pacific Northwest

The eastern population is believed to spend the winter near Mexico and Central America.
The western population appears to feed in the summer in the southwest of Kamchatka, south of the Aleutian Islands, in the Gulf of Alaska. In winter, they migrate to lower latitudes in the western Pacific and, less commonly, to the central Pacific, including Hawaii.
Blue whales accompanied by calves are often observed in the Gulf of California from December to March; this area is probably important for the birth and feeding of whales for this species.
Blue whales have been seen in the Gulf of Aden, the Persian Gulf, the Arabian Sea, the Bay of Bengal, near Burma and the Strait of Malacca. The migration routes of these whales are unknown.
In the Southern Hemisphere, two subspecies are distinguished, they mainly live near Antarctica directly near the ice border.

Blue whale population

Blue whales have been significantly depleted by the commercial activities of whaling fleets around the world.
There is no accurate estimate of the number of blue whales in the eastern waters of the North Atlantic. In 1997, 32 whales were photographed in Icelandic waters.
Additional studies have shown that the population size near Iceland and neighboring waters can be from 100 to 1000 individuals. Observations made off the western and southwestern coasts of Iceland show that the number of blue whales in this region has increased by 5% per year since the late 1960s.

Threats to blue whales

The main threats to whales currently are:
ship collision
poaching
Additional threats that could potentially affect the population include:
anthropogenic noise
habitat degradation
ocean pollution
growing number of courts
long-term climate change
Note:
Whaling has significantly reduced the number of blue whales around the world, a ban on catching whales, adopted in 1966, put an end to the threat of extermination due to industrial fishing.

Severe injuries caused from collisions with ships can be one of the main threats to blue whales.
The average number of blue whales in California that are killed by ship strikes averaged 0.2 per year 1998-2002.
In the western North Atlantic, at least 9% of whales in the Gulf of St. Lawrence have injuries or scars that are characteristic of ship strikes. This region has a relatively high risk. In the area of ​​the Gulf of St. Lawrence, there is a very large traffic of ships at all times of the year, and blue whales in other periods accumulate in that region in significant numbers.
There is no threat from the direct capture of whales - it is prohibited. However, whales can become entangled in nets and trawls.
There are two documented whale deaths due to these causes, one in 1987 and the other in 1990. However, in practice, such cases can be many times more.

How exactly anthropogenic noise affects the whale population is not yet known, but it is considered as a negative factor in the habitat.

Habitat degradation (eg chemical pollution) has occurred in some areas of the North Atlantic (Gulf of St. Lawrence River), but the effects of this degradation have been little studied.
From the 1890s to 1966, blue whales were hunted in all the oceans of the world.
At least 9,500 blue whales were taken by commercial whalers in the North Pacific from 1910 to 1965. At least 11,000 blue whales were caught in the North Atlantic between 1890 and 1960.
In 1966, the IWC banned the commercial hunting of blue whales. However, illegal whaling of blue whales has been reported.
A small number of illegal blue whale catches have been reported in the North Atlantic off the coast of Canada and Spain, in the eastern North Atlantic.
Blue whales were taken in the Southern Hemisphere by the Soviet Union after 1966 (Zemsky et al., 1995, 1995).
Illegal whaling in the USSR has been recorded in the northern part of the Pacific Ocean (Yablokov, 1994).
Norwegian whalers only target minke whales.

Blue whale conservation activities

Blue whale conservation activities include:
Monitoring carried out by questioning ship captains;
Implementation of measures to reduce the number of collisions of whales with ships;
Placement of observers on board ships;
Implementation of measures to reduce fishing for marine mammals;
In 1998, the NMFS published the Blue Whale Whale Recovery Plan. In April 2012, an update to the blue whale recovery plan was announced.
The blue whale is listed in the Red Book. Internationally, blue whales received full legal protection from commercial whaling in 1966 under the International Convention for the Regulation of Whaling.