II. Råstoffkilden

Whale and fish live exclusively in water, But while the fish's ancestors have always lived in the sea, tribes whales from mammals that lived on land. Through a long development they adapted to life in the sea, and with this development, there followed so many changes in building and way of life that the whales, such as we know them today, not very similar to the ancestors that were predators on land.

The body is streamlined and skin hairless and smooth, so that the animals slide easily through the water. forelimbs (flippers) is well developed, and forelimbs skeleton are the main features of full compliance with those found in land mammals. Clean the exterior set of memories flippers on the fish's pectoral fins, and they have about the same functional significance as these. They are above all rule- and equilibrium organs, but they also serve as a brake body. This design of the forelimbs, we can see as an adaptation to life in water. Whales have no visible tailgates. If we dissect a whale approximately at the place where one would expect to find hind limbs, however, we will in muscles detect a pair of legs which are relics of the whales' pelvis and hind limbs. The tail fin is well developed, and it is horizontal, which is important for animals particularly moves up and down in the sea. Whales have the up to the surface to breathe.

Whales' senses are carefully adapted to life in water, and both anatomical studies and observations show that the senses as whales have particular utility for the environment is well developed, while on the other hand, senses that less importance is poorly developed or even completely disappeared. Odor and taste belong to the latter category, in toothed whales are not at any smell nerve. On the other hand see and hear the whales exceptionally well.

Outline of the skeleton of the left crank from (top-down) a) North Atlantic right, b) blue whale, c) pilot whale and d) gange dolphin (by Howell).

The eyes are very small compared to the animals size. Interest anatomical remind the deal about fish eyes, primarily because the lens is nearly spherical- shaped, and this building shows that whales look good on short distances in water. At the least to some extent, can see through the air, show trials that are done at Marine Studios, Florida, where small toothed whales captive large pools. It was ascertained that the animals through the air could see things that were moving at least 50 walking distance. Also otherwise is reflecting building in whales adapted to life in the sea. These membranes that surround the eye is unusually thick, eye muscles are solid and inelastic, and eyes are able, to withstand the water pressure when the whales stay in deep waters.

One has long been aware that whales hear very well, but until recently it has been difficult to find a reasonable explanation of how sound waves are transmitted to the inner ear. This is partly because certain aspects of the ear canal. At tannhvalen is the immense craving, with baleen any further, but in return completely tilproppet in the inner part of a wax-like plug.

Because of these conditions thought a long time that the sound waves were transmitted to the inner ear through the skull. Now, however, British researchers have been able to show experimentally that the earpiece is a very good conductor of sound. Similar investigations of the ear canal walls and other parts of the ear clearly shows that meatus whales are highly functional, and that lydbølgene gets transferred through it to the inner ear.

In the last time there, at Marine Studios in Florida made interesting experiments relating to tooth whales' hearing. One has been able to demonstrate that when searching for food, produces the sounds, and they are capable of capturing echo for example from fish. In this way they are oriented about the direction changed is finding. In the context of this can be mentioned that a Dutch researcher recently discovered that certain anatomical aspects of the whales' inner ear is very similar to those found in the bat. The bat, as known by a kind of radar mechanism; it sends out an ultrasound echoes from fixed objects bat avoided because the scavenger echo aurally.

Whales spirits with congestion, which is not different building than the lungs in other mammals, but airways are modified to life in water. In land mammals, it is completely open connection between the nasal opening and oral cavity, but In whales larynx formed so that it protrudes into the inner nose opening and forms a direct connection between the nasal passages and trachea. The outer nose opening, or blow hole as it is called, closable, and whales are therefore no water in the lungs when the diver, Although the oral cavity is filled with water.

The greatest depth which we certainly know that a whale (sperm whale) can go down to, is closer 1000 meter, and this corresponds to a pressure of approximately 100 atmospheres or 100 kg pr. cm2. To understand how they manage this, we must first remind what diver flu is something. Along with oxygen takes blood also up slightly kvelstoffgass from the air in the lungs, and the amount that can be absorbed and can remain dissolved in the blood, is dependent on the pressure. When a diver is down 10 or 20 meters, breathe his air of 2, respectively 3 atmospheres of pressure and blood then takes up 2 or 3 times as much as usual kvelstoffgass. If he then goes quickly up to the surface, will kvelstoffgassen fizz out of the blood in small gas bubbles just like the fizz out of a soda bottle being opened. The small gas bubbles can be caught in the capillaries around the body and cause serious disturbances in circulation. This is decompression sickness. When whales dive, providing chest to the pressure in the water, and the air pressure in the lungs increases correspondingly. One would therefore think it was ery advantage to have little air in the lungs when a diver, and we know that the seals quite rightly exhale before they go down, while whales, As far as we know, goes down with air in the lungs. When they come up again, is at least the first one sees that they exhale. But whale air pipes are large relative to lungene, which are elastic so the frykkes easily along, and as they are pressed together, air is forced into the rigid airway. At one fin whale is the size ratios of the airways and lungs so that all the air will be pushed out of the lungs and over 1 airways in about 100 meters, and respiratory taking blood not up some gas. It would thereafter be relatively small depth, less than about 100 m, which would be dangerous for whales. But it is a factor to that is of importance. As the lungs are compressed, is lung wall thicker and gas exchange between blood and lung air is slower and more difficult for them, and the risk of decompression sickness are less.

Some whale species may reside 1/2 hour or more under water. This is because the blood and muscles are very rich in pigment hemoglobin, which binds oxygen in large amounts and forms bearing for the oxygen needed during diving. Certain anatomical features of the blood vessel- system that particularly the brain and nervous system are well supplied with oxygen at depth, while muscles wreaks havoc on the oxygen amounts they all have in muskelhemoglobinet, and otherwise form an oxygen debt being avbetalt when the animal again surfacing.

The adaptation to life in the sea so far mentioned, apply for whales in general, but within the different groups of whales we find other matching conditions, with. a. such that reflects specialization in exploiting different food animals in the sea. Some have baleen and others have teeth,and by this relationship we share the whales into two large main groups, baleen whales and toothed whales.

Of baleen whales, we only know 10 ensure species, is around 65 species of toothed whales. Among baleen whales we find the major species, and the blue whale is the largest of them, can grow up 30 m. Toothed whales are relatively small, only sperm males can be as large as up to 20 m. Another difference between the two main groups are the baleen whales females are always larger than males, while males are highest in toothed whales. One can also find many purely anatomical differences, f. example. baleen whales have two nostrils, symmetrical cranium and mandible as rakes front of- jaw, while toothed whales one nostril, asymmetrical skull and- jaw as long or longer than the lower jaw.

Within bardehvalgruppen we 3 families - right whales, gray whale (i art) and fin whales. Right whales' best-known representatives are the bowhead whale and nordkaperen. They lack both ventral grooves and dorsal fin as opposed to fin whales (blue whale, find whale, seihval, Bryde's whales, minke and humpback whales) newly characterized by having ventral grooves and dorsal. Gray whale is systematic in an intermediate position; the lack dorsal, but from 2 to 4 short furrows under throat.

 

The economically important Antarctic whale species, rendered to the same scale, top-down. a) blue whale, b) find whale, c) seihval, d) humpback whales, e) Sydishavets retthval and f) sperm whale (by Peter).

Scheme of whales affinities. (For toothed whales concerned are only the best known genera and species taken.) (after Johnsen 1959.)

Within toothed whale group, we distinguish between the species resembling sperm whales and those who resemble dolphins. The former, whose most famous representatives are sperm whales and bottle discus, characterized bl. a. the tooth-set is extremely reduced, while the latter group has many teeth in both jaws. For dolphins belong bl. a. whitefish, killer whales and pilot whales. Ferskvannsdelfinene, found in tropical rivers (f. example. Ganges, Amazon- the river), is easily recognizable on the long nose reminiscent of a proboscis. They form a separate family of toothed whales.

The whales are found in all oceans; some migrate over large ocean areas, while others are more stationary. Greenland whale, white fish and mock whale occurring b., example. only in Arctic waters, gray whale only in northern Setting- hav, whereas blue whale, fin whale, humpback whale and orca is almost cosmopolitans! That does not mean the individual animals making migrations to virtually all waters where the species exists. On the contrary, all indications are that we are dealing with strains of whales to do that wander within relatively restricted areas.

Pilgrimages we know especially for those species that have been the subject of trapping, and experience shows that the animals' behavior in the different waters follows the seasons. Bardehvalene f. example. walk in the spring months towards higher latitudes in the north or south, because phytoplankton bloom then is greatest in these areas. With plankton follow good åteforhold, and it is precisely for food's sake baleen whales make this pilgrimage. We call it therefore an industry migration. During autumn months draws animals in the lower latitudes, and in winter, the pups are born and animals mate. This migration is called a reproductive migration. At these low latitudes, the sea warm, and when the kids are born here, they avoid the large heat loss as they would be exposed to if they come into the world in the Arctic Ocean in the north or south.

Sperm whale occupies a special position with respect to both distribution and walks. It is polygamous, ie that a male has a harem of females.
In the harem it is otherwise too small, immature animals of both sexes. Such harems occurs only in tropical and subtropical waters. Many adult males hand wanders northward or southward poured into Arctic.The.

Some of what we know about migrations caused by the tagging of whales, and it is mainly in the Antarctic whale marking has been made. From 1932 to 1966 is around 5500 blue whale, fin whales and humpback whales have been tagged in this important catch area, and well 3oo of them are caught later. The labeling has particularly good results with regard to Humpbacks occurrence and walks in the southern hemisphere. Evidence suggests that in Sydishavet in all, 5 humpback whales- strains which do not mix with each other, but migrations within these strains are only partially known. There seem to be certain that the animals migrate regularly back and forth between breeding areas in warm waters and åteområder in Antarctic Ocean, and migration routes they follow goes something in the direction north-south. On the other hand, they wander little in the direction east-west. The strain we know best is also the most abundant. This tribe's winter off the coast of west- and northwest Australia, summer at roughly corresponding longitudes in the Antarctic.

When it comes to blue- and fin whales, has noticed results also given us some information about the tribes of whales, and that migrations to warmer waters takes place in the propagation time, gives marking an indication of. A fin whale marked in the Antarctic Ocean in February 1935 was caught off Saldanba Bay in South Africa, the 1. July 1937, and a fin that were marked the 11. Oct. 1937 in South Atlantic off the coast of Brazil, was caught in the 7. jan. 1949 at South Georgia. All other branded blue- and fin whale caught in Sydishavet.

We have the most recaptures of fin whales, and these provide interesting information about fin the proliferation. Up to and including 1962 was well 200 branded fin whales caught again. It turns out that 66% of those who were caught again by the year after marking, were taken on so be liberated say the same place as they were marked. The fin whales that were trapped more than 2 years after marking took place, have walked any more, in it 40% were taken to mark the spot. On the other hand seem older fin whales to be more stationary than younger, which presumably means that the animals gradually become established in a specific åtefarvann.

 

Over: Sydishavets krill, Euphausia superba, approximate actual size. (Photo: Uwe Kils)
Right: Calanus, Calanus finmarchius. (Photo: Hopcroft / UAF / CoML)

Baleen and teeth are, each in its own way, in of nutrition service, and it is easy to understand that there must be a significant difference in the food baleen whales and toothed whales feed on.
On each side of the upper jaw of baleen whales we find 300-400 thin horn plates, sitting close by each other. Each plate is shaped like a long triangle, and the short side is attached to the upper jaw. One of the long sides facing the lake, the other long edge oral cavity, and this side edge is shredded into thin, free hair. The hair is tangled more or less together with the hairs fira neighboring plates. When we take a look into the mouth of a baleen whale, therefore see it as it has a shaggy mat on each side of the upper jaw, and this is the screening apparatus which is so dense that it can screen small animals fira seawater.

Baleen whales feeds mainly on small planktonic crustaceans, Calanus and krill, sometimes small schooling fish such as capelin and herring.

Blue whales and sei whales eat exclusively crustaceans, blue whale krill and sei whales extensively only copepods. It may seem strange that it is possible for sei whales to catch as far as small crustaceans such as copepods, that is no more than a few millimeters long, but if one studies the sei screening apparatus closer, For a explanation for this. It has both a greater number baleen and thus more snug baleen than other baleen, and moreover bardehårene much thinner and softer so that the screening apparatus is extremely fine mesh. The fin whale and humpback whales live significantly krill,,but often one can also find small schooling fish of different kinds of stomach- content. The minke whale is the of the baleen whales apparently appreciate about fish. Although krill is arguably its most important food, gorge the plumb, herring and strain when the opportunity arises. Even larger fish such as haddock, pollock and cod can take, at least in the spring and early summer when the industry migration to the high northern latitudes.

Toothed whales can not live by catching small crustaceans. Teeth are often gripping teeth, which is intended to capture a larger swap, which is then swallowed. The species that have few teeth, feeds mainly on squid. This applies f. example. both sperm whales and bottlenose. Most species have many teeth, live fish, and then feel small fish. Killer whale is a nature, but it lives besides of mammals. It takes extensively seals and porpoises. Killer whales generally have in each jaw 24 powerful teeth that join together when the mouth is closed. They are therefore superbly suited to tear prey apart, but the orca may also, apparently without further exertion, cap f. example. one porpoise in two parts.

baleen of: a) Greenland whale, b) North Atlantic right, c) blue whale, d) find whale, And e) cross-section just in front blow hole through the head of a blue whale, showing how baleen is placed in the upper jaw (schematically, by Peter).

To the left: Detail of barde (Photo: jkirkhart35, Wikipedia). Over: Through Named earpiece from fin whales, showing growth structure (by Johnsen 1959).

The whales propagation is no different mammalian, except that marine life naturally brings with it certain modifications. As many land mammals have whale a more or less limited rut period. Mating takes place also in the same manner as in land mammals, likewise birth, even if it becomes more difficult, because it takes place in the sea. In studies of individual small toothed whales in the aquarium has been determined that the birth, at least for these species concerned, takes place under the surface. Tooth whale kid is born tail first. Usually get the whale only one young at a time. The kid swims just after birth unassisted to the surface and breathe for the first time, and it swims so well that under normal conditions does not have any difficulty to follow mother. Patting takes place in the way that the child engages sugevorten while the mother with contraction of certain muscles pressing the milk into the throat of the kid. Using tongue ensures kid that water does not flow into the mouth along with the milk. The kid feeds exclusively from the mother's milk in a few months, a little different for different species of whales. Eventually, supplementing the diet with other suitable food, and finally leaving the mother and begin their own independent existence.

Particularly in pattetiden growing whale kid strongly. Whale milk is very nutritious, and the composition is different from the milk of land mammals. Whale milk is usually 30-40% fat, as much as fine whipped cream. a blåhvalunge, at birth is about 7 meter, becomes during pattetiden, that is about. 7 months., around 16 m. During this time placing it on an average of approximately. 100 kg pr. day.

 

The composition of milk of some whale species in grams per. kilos of milk.
(after Heyerdahl, Schmidt-Nielsen & Frog, Takata, T. Pedersen)

After the whales have stopped patte, we have clear grounds for judging av their age. In the late twenties they examined British researchers Mackintosh and Wheeler called the corpora lutea in the ovaries of sexually mature blue- and fin whales. They found that the number of corpora lutea could be used as an approximate measure of age, because each ovulation as females have had after being sexually mature, has left a yellow body ova- reed. Later, other researchers use of this ratio as a basis for age determination. I 1940 showed Norwegian and Russian scientists independently of each other, that baleen have growth zones which by all accounts is annual. From then on it has been possible to extend the age determination to include immature animals and males. The method, however, has its limitations, the baleen frictional wear of the tip. When the animals are older than 5-6 years, it is difficult to determine how many annual growth zones that are worn away. Yet the method has given important results. One, for example, been able to show that blue whales and fin whales reach sexual maturity respectively 3-6 and 2-5 years old, while one by earlier studies thought that both these species were sexually mature when they were 2 year. On the basis of results that bardemetoden has given, it is possible to estimate the total mortality for fin whale in the Southern Ocean.

I 1955 took British researchers used a new method of age determination of whales which are based on the following conditions:
The inner part of the meatus of baleen whales as previously mentioned to- propped by a wax-like plug, and the study of whales hearing discovered that the plug had distinct growth zones.

Yet we have no conclusive evidence that the number of growth zones are in any particular relation to age, but if the method keeps what it seems to promise, it also becomes possible to determine the age of ancient whale. Researchers in several countries are working on the problem, and significant results can be expected in the next few years.

 

Determination of the whale's age and growth has proven to be a very difficult task. About Blue Whales, we know that it grows rapidly, no studies in the recent past (Ruud & Jonsgård) indicate that growth does not take place as quickly as previously thought (Mackintosh & Wheeler).

Whale marking in the Antarctic Ocean have helped to provide information about how old whales can be. We now know with certainty that the blue whale and the fin whale least can be 20 years old, and it is also fairly certain that they are even older. The extensive whale marking which was carried out in the Southern Ocean in the mid-30s, will in the next few years probably give us new chain ensgj erning on blue- and fin whales age.

 

Some data for illuminating the age and weight of the Antarctic blue- and fin whales.
(Significantly for Mackintosh & Wheeler.)

The feed amount as a single whale represents, is quite impressive. A blue whale weighs up 150 000 kg., the other species relatively less. In recent years there have been a total of taken about. 50 000 whales a year of the species that are included in the International Whaling statistics, and of these species average weights can estimate the total amount of feedstock whaling industry accrue, to about. 2 million tons of raw material per year. By comparison, we can mention that the raw material of the total Norwegian fisheries are of roughly the same magnitude.

The raw whale gives us, consists of: killer, meat, legs and internal organs. The weight ratio of these components is dependent on the species of cetacean we have for us. Right whales have f. example. a much thicker blubber than fin whales, a relationship that allows the right whales float after they are killed, while fin whales sinks. That was why it was possible to catch right whale with the primitive tools one possessed in the old whaling.

 

A blue whale on 100 mt compared with elephants and bulls,
the blue whale = 25 Elephants = 150 large bulls (by Peter).

Average length and weight of 32 blue whales and 29 fin whale caught in Sydishavet, and the amounts of meat, killer, bones and internal organs calculated as a percentage of total weight. (after Nishiwaki)

The amount of raw material that we receive from the various whale species, alternates with their size and their condition. Any whaler who participated in the catch, f. example. i Sydishavet, know that whales are thinnest in the beginning of the season, and that the leanest of the lean is the females who have or have recently had pattunge. As the season goes on, put animals on again. They gorge on the bait, not only to meet their daily nutritional requirements, but also to gather support industry. Killer layer increases in thickness, and fat are deposited in muscle and bone.

It is this surplus of nutrients animals since use in propagation- period while they stay in waters where there is little of the bait animals need. The need for circulation industry is naturally greatest for those females who have fetal, because they'll bring a young to the world and since produce all the milk that pattungen to live by.

The raw material source whales represent are not inexhaustible. Time and again, catch history has shown that fields have become unprofitable because whales do not have endured taxation. One can understand that when one knows that the whales' ability to renew the population is relatively small. Therefore, only by regulating engagement we can hope to preserve a whale population as a raw material source for posterity.