Boreal Fin-back whale

The boreal fin-back whale , or Balaenoptera borealis , is a whale with pennons and, behind the Blue whale and the common Rorqual, the larger third Rorqual in the world. It is present in all the oceans and all the contiguous seas, with a predilection for the open sea and the deep oceans. It avoids the icy water and tropical be as well as the half-closed seas. The boreal fin-back whale carries out an annual migration of the cold and sub-polar seas in summer, towards the moderate and subtropical seas the winter, although in the majority of the areas of the sphere one is unaware of his precise roads of migration. They introduce daily on average 900 kg of food, consisting primarily of copépode S, Krill, and other forms of Zooplancton. They count among the swiftest Cetacea, with a speed of 50 km/h on short distances.

In consequence of the industrial fishing which, between the end of, decimated this species with more: 238000 catches, the boreal fin-back whale is today recognized “protected space” by the international agreements , although a limited hunting remains authorized within the framework of discussed “research programs”, carried out by the Iceland and the Japan. For the year 2006, the world population of rorquals polar was of: 54000 individuals, is close to a fifth of manpower to before the whaling. In Japanese, its name is iwashi will kujira , or “whale sardine”, because it was observed that this fin-back whale nourished also this fish in the Pacific.

The boreal fin-back whale belongs to the family of the Balaenopteridae, which includes/understands the Humpback whale, the Blue whale, the Rorqual of Bryde, the common Rorqual and the Baleine of Minke. The word “ fin-back whale ” comes from the Norwegian “ röyrkval ”, which means “whale with furrows”, because the representatives of this family carry series of scratches or parallel furrows longitudinal since the lower lip to the ventral face. In the order of the evolution, one supposes that the family of the Balaenopteridae separated from the Mysticeti (also called “whales with pennons” or “large whales”) about the middle of the era Miocène. However, one is unaware of in detail at which time the various representatives of the family of the Mysticeti , comprising the Balaenopteridae , knew a divergent evolution.

One identified two Sous-espèce S — the boreal boreal fin-back whale ( Balaenoptera borealis borealis ) and the boreal fin-back whale of Schlegel ( Balaenoptera borealis schleglii ). They are indeed distinct and live in quite separate surfaces.

Systematic

Description

The boreal fin-back whale is by its size the third representative of the family of the Balaenopteridae, behind the Blue whale (until 180 tons) and the common Fin-back whale (until 70 tons). With the birth, a whale-calf measures 4&ndash in general; 5 meters., of the family of the Lamprey S (family of Petromyzontidae), even with the wild Squalelet ( Isistius brasiliensis ). The dorsal fin is high (of 25 with 61 sickle-shaped cm), ; it is drawn up with the two-third of the body on the basis of the muzzle. The shape even of this fin, the cutaneous pigmentation and the scars are used up to a certain point to identify the rorquals on the photographs. The tail is thick and the caudal fins or “ lobes ” relatively small are compared with the size of the animal.

The boreal fin-back whale is nourished by filtration of the water which it introduces: its Fanon S lets pass only initially swallowed water, the plankton coming to plate itself on the inner face. An adult has from 300 to 380 pennons on ashed each side of the mouth, and measuring each one close to 50 cm length. Each pennon, fact of horn or Keratin, end in filaments blanchâtres turned towards the interior of the mouth close to the Langue.

The boreal fin-back whale being very similar to the others rorquals, the best means of distinguishing it from the Rorqual of Bryde, if one excludes the differences mentioned previously, is the presence at the fin-back whale of Bryde of side grooves on the dorsal face of the head. One could still confuse the boreal fin-back whale with the common fin-back whale, if it is only at the latter, an asymmetry of the skin color on both sides of the head is quite locatable: while the bottom of the right cheek is white, the bottom of the left cheek is gray. Seen side, the higher face of the head of the boreal fin-back whale is slightly convex between the point of the muzzle and the eye, whereas the profile of the common fin-back whale is rather flat, or in small group to six specimens.

The boreal fin-back whale counts among the fastest Cetacea: its speed on short distances can reach 50 km/h. It was also shown by analysis of the DNA contained in deposit taken near the boreal fin-back whale with nets. The fin-back whale is in competition with the other predatory ones, in particular the clupéide S (i.e. fish connected with the Hareng), the Basking shark, and the whale with pennons.

In the North Atlantic, the boreal fin-back whale nourishes mainly the Copepoda calanoïdes, more precisely of Calanus finmarchicus , then (and by order preferably) of euphausiides (krill), in particular Meganyctiphanes norvegica and Thysanoessa inermis . In the Peaceful North, the boreal fin-back whale nourishes similar species of zooplancton, namely the Copepoda Calanus cristatus , Calanus plumchrus , and Calanus pacificus , as well as the euphausides: Euphausia pacifica , Thysanoessa inermis , Thysanoessa longipes , and Thysanoessa will spinifera . Moreover, it is known that it introduces animals of bigger size, like the Japanese Toutenon (and more specifically the Todarodes pacificus pacificus ), and of small fish of the kind Engraulis (Anchois), Cololabis (sauries), Sardinops , and the Trachurus (chinchard). Some of its preys have a commercial interest. With broad of the California, one observed that the fin-back whale nourished Anchois from June to August, and of Krill ( Euphausia pacifica ) in September and October, 11 months and a week, even a year. These differences in estimate come owing to the fact that one could not, up to now, to observe the totality of the period of gestation of this animal; the majority of information available on the reproduction of the rorquals are drawn from observations made by hunters of Cetacea, which offers only one very partial point of view on the fetal growth. This is why the researchers determine the date of design by extrapolation between the size and the physical characteristics of the fetuses and the whale-calves newborns.

The newborn is separated towards the age of 6– 9 months, in summer or with the autumn, and it is then in the benches of krill; its size is already of 11– 12 Meter S.

Song

Habitat and migration

One finds the rorquals boreal on all the seas of the sphere, although they abstain from attending the water polar S and Tropical are, in the pits circumscribed by submarine plateaus, or above the throats traced in the underwater Canyon S.

With regard to the Peaceful northern, one finds the fin-back whale boreal under the Latitude S of 20°N– 23°N latitude the winter, and between 35°N– 50°N of latitude the summer. Nearly 75% of the total population of the rorquals of the northern Pacific lives in the east of the Date-line, but the insufficient number of markings makes these two individuals an isolated case. In the southern Hemisphere, the distribution in summer, estimated according to various markings, is concentrated between 40° and 50° southern latitude, the distribution the winter being still unknown. In the Atlantic North-East, the boreal fin-back whale will hibernate more in the south to the coasts of Mauritania then again skirts the continental Slope towards north in spring. The largest females, which carry out this migration towards north until the course Skagerrak, reach their destination more quickly and more surely than the other sex and than the other species: arrived to destination mid-July, they remain there until mid-September. Certain years, the younger males and females remain with lower latitudes during the summer months. F.O. Kapel put in report/ratio the occasional presence of the boreal fin-back whale at the west of the coasts of Greenland and its incursion into relatively hot water of the Current of Irminger towards this area. Certain marking campaigns show that isolated individuals return off the coasts of Iceland each year.

Whaling

The invention of the explosive harpoon and the development of the whaler with vapor at the end of the XIXe century made it possible to the owners to fish specimens of a size which it was formerly inenvisageable to drive out. The boreal fin-back whale, from its speed and its capacity to thwart the operations of the harpooners on the one hand, and on the other hand because of his weak report/ratio in Oil and meat, was relatively saved by the man. But when the benches of the more required species (Right whale, Blue whale, Fin-back whale common and Humpback whale) had been suddenly dried up, i.e. between 1950 and 1970, the hunting of this animal became systematic. The meat of fin-back whale was required in Norway, and only the rise of the courses of this food product explains why it was profitable to continue the hunting of a mammal particularly difficult to catch.

In Iceland, the fishing port of Hvalfjörður recorded 2.574 catches between 1948 and 1985. But since the beginning of the years 1970, the demand for meat of Cetacea of quality overriding the demand for Oil of whale, the boreal fin-back whale is more regarded by the Icelanders only as one “second choice” behind the Rorqual common since the years 1920

by the Canadian whalers to broad of the continental shelf of Nova Scotia between the end of the year 1960 and the beginning of the year 1970. The coastal Slaughter-house S of the Japan and Korea cut up between 300 and 600 rorquals of this species between 1911 and 1955. For Japan, the record of catches corresponds to the year 1959, with 1.340 catches. The intensive fishing of the deep-sea whalers in the northern Pacific started with the beginning of the year 1960, with 3.643 catches per annum on average between 1963 and 1974 (either a total of 43.719; the result varied during this period between 1.280 and 6.053 catches per annum). In 1971, after one decade of industrial fishing, the species started to rarefy in Japanese territorial water, and it whaling was abandoned in the north-western Pacific in 1975. The slaughter-houses of California cut up 386 individuals between 1957 and 1971. The boreal fin-back whale profited from a complete protection in the Northern Pacific only as from 1976, and one fixed catch quotas for this species in the North Atlantic only in 1977, the benches of the southern hemisphere being covered by these agreements only in 1979. Noting the progressive extinction several species of Cetacea, the Commission international whale-boat voted a moratorium on the whaling which came into effect in 1986: since, fishing with the boreal fin-back whale is prohibited, and although there is no direct proof of the absence of similar companies in the northern Pacific, the faked data transmitted by the Soviet Union give rise to think that the official statistics are not reliable.

This species is reproduced still today on the red Liste of the UICN, in the category Espèce in danger of disappearance .

The Japanese researchers kill each years approximately 50 rorquals per annum within this same framework. It is the Institute off Cetacean Research (ICR) of Tokyo, a deprived institution with not-lucrative goal which is responsible for the program. The finality of this program is to determine the mode of food of the boreal fin-back whale, and to deduce this Cetacea up to what point from it enters in competition with the fisheries. Dr. Seiji Ohsumi, Managing director of the ICR, declare on this subject: “one considers that the whales introduce from 3 to 5 times the quantity of fish necessary to the provisioning of the men, which explains all the interest of information that we collect for the improvement of the management of the fishing resources. ” He added thereafter: “… the boreal fin-back whale is the second most widespread species of Cetacea in the Pacifique North-West, with a manpower estimated at more than 28.000 individuals. It is obviously not a threatened species. ”

Associations militant for the safeguarding of nature, like the World Wildlife Fund, dispute this research appropriateness, and recall that it is well-known that the boreal fin-back whale basically nourishes useless resources with the man, like the Calmar and the Plancton, and does not fold back itself on the Poisson that in last spring. They affirm that these programs “are anything else only one operation intended to maintain the activity of the fleets of whalers, and present the whales like a scapegoat providing an alibi to sur-pêche of the men.

Recent estimates on the number of individuals

It is estimated today that the total staff complement of rorquals boreal is not any more that of 54.000 individuals, that is to say approximately a fifth of the population of before fishing industrial whale-boat. This study was based on a technique of census spread, the “ wrestling per links effort ” (CPUE), which estimates manpower starting from a correlation between time and the means implemented to count to a given number individuals of the required species. This method is however criticized by the scientific community and is not regarded as a reliable measurement of abundance. One said in the years 1960 and at the 1970 qu beginning ' off the coasts north of Norway, where the boreal rorquals were captured in great quantity between the end of the XIXe century and the Second world war, these animals were done rare. Among the explanations advanced to explain this rarefaction, there is that which stresses the overfishing of the Cetacea. The countings carried out in the Kattegatt gave 1.290 Cetacea in 1987 and 1.590 in 1989, while no individual was detected off the coasts of the Oregon and the State of Washington. It is estimated that there were 42.000 individuals in the northern Pacific before fishing industrial whale-boat. It is estimated that there were approximately 65.000 rorquals in the southern hemisphere before fishing industrial whale-boat

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