Rorqual Whales

Blue Whale blue (Balaenoptera musculus)

The Blue Whale is found throughout every ocean in the world, from the equator to the polar regions in both the Southern and Northern Hemispheres. They migrate to polar waters in summer for feeding and return to warmer seas in winter for breeding - thus covering thousands of kilometres every year. The subspecies, the Pygmy Blue Whale (Balaenoptera musculus brevicauda) is found mainly in the Southern Hemisphere.

Classification: Linnaeus classified the Blue Whale in 1758, calling it Balaenoptera musculus, meaning 'Little Mouse'. The name Balaenoptera musculus musculus is given to Blue Whales inhabiting the Northern Hemisphere, whilst those occupying the Southern Hemisphere are known as Balaenoptera musculus intermedia. In 1963 a smaller subspecies, Balaenoptera musculus brevicauda (Pygmy Blue Whale) was recognized.

Local Names: Sulphurbottom (referring to the yellow-brown appearance of algae on the skin after the whales have inhabited polar waters); Sibbald's Rorqual; Great Northern Rorqual.

Description: This is a streamlined and slender whale, with a small dorsal located about three-quarters of the way along the back. The tail flukes are large and notched, and flippers are slender and pointed. It is darkish blue-grey in colour, with a mottled appearance and a pale underside with 55-88 throat grooves. The Blue Whale is about 25-26.5m in length, but the longest recorded was 31m, with females are generally larger than males. It weighs between 100-120tonnes, the heaviest recorded was a female weighing 200tonnes. There are about 540-790 coarse black baleen plates per animal, each about 1m in length.

Recognition at Sea: Any rorqual exceeding 24m is likely to be a Blue Whale. The dorsal fin is not immediately obvious because of its position. The Blue Whale's blow is vertical, measuring about 9m in height.

Habitat: This species is rarely seen near the coast, except in polar regions when it follows the retreating ice-edge. This in turn can cause entrapment by ice as the weather changes, which is frequently recorded in the Gulf of St Lawrence in Canada.

Food & Feeding: The main stomach of the Blue Whale can hold a tonne of its primary food source, euphausiids (tiny plankton), which it specialises in consuming in the Antarctic. Since euphausiids are also the primary food for Fin, Sei and Minke Whales, the Blue Whale is in direct competition with these species for food.

Behaviour: Blue Whales are not strictly gregarious in manner, and is usually found either in pairs (as in mother and calf) or as a solitary animal. However, this species has been found to congregate on the feeding grounds, and do not, as a rule, dive deeply (maximum 200m). Moans, pulses, clicks, rasps and buzzes, as well as breaching and lob-tailing are the primary means of communication between individuals.

Longevity: Approximately 80 years.

Estimated Current Population: < 5,000 animals. Endangered.

The Influence of Man: Once fast catcher boats and explosive harpoons became available in the latter half of the 1800s, all rorquals were catchable and, as the largest was most profitable, the Blue Whale became the primary target. Catches were made primarily on the summer feeding grounds - the North Atlantic, Northe Pacific and mostly, the Antartic Ocean. Nearly 30,000 animals were taken in 1930, and the raw churning power of the largest creature in existence almost left the planet forever. By 1966 when the species received global protection only a century after it became the most hunted creature on Earth, over a third of a million Blue Whales had been slaughtered.

Bryde's Whale (Balaenoptera edeni)

The Bryde's Whale (pronounced 'Broodahs') has a worldwide tropical to warm temperate distribution. It does not migrate; instead it moved from inshore to offshore waters, following food, and is chiefly resident year-round.

Classification: In 1878, Anderson described and named the Bryde's Whale, Balaenoptera edeni. However, in 1912 Olsen described a species seen off South Africa and named it Balaenoptera brydei after the Norwegian Counsel to South Africa, Johan Bryde. Eventually, it was found that both descriptions referred to the same species, and so the original 1878 classification was retained, with the common name deriving from the 1912 classification.

Local Names: Tropical Whale.

Description: This cetacean is similar in both size and appearance with the Sei Whale, and the two are often confused. However, the Bryde's Whale is generally shorter, stocky and slender, with a well-defined dorsal fin set two-thirds back down the body. The tail stock is compressed, with broad, notched flukes, and pointed flippers. The body colour is dark grey with some white coloration on the chin and throat, occasionally with paleness down the back between head and dorsal, extending down the flanks. Pock marks from parasites or small sharks add a mottled appearance, and there are two distinct ridges on the head, either side of the midline. There are between 40-70 throat grooves, and 500-730 baleen plates per animal, the maximum length of which is about 60cm. Females are generally larger than males, and the Bryde's Whale measures about 13-16m in length and weighs between 16-25 tonnes.

Recognition at Sea: The two ridges on the head either side of the midline easily distinguish this whale from others. The blow is vertical, 3-4m high in a 'cloud'.

Habitat: This species is found in either inshore and offshore waters, preferrably those with a temperature above 20°C.

Food & Feeding: The Bryde's Whale consumes whatever shoaling prey is available, and often exploits the activities of other predators, swimming through and engulfing the fish they have herded. Therefore, it is frequently found in areas of high fish abundance, along with seabirds, seals, sharks and other cetaceans.

Behaviour: Bryde's Whales are not gregarious in manner and either swim alone or in pairs. The largest group sizes of 10-23 animals are usually loose congregations covering a few square kilometres when feeding. The Bryde's Whale dives to a maximum of about 300m and communicates via moans, pulses, clicks, and grunts, as well as breaching.

Longevity: Approximately 50 years.

Estimated Current Population: 40-80,000 animals.

The Influence of Man: Many Bryde's Whales were included in the 1960s catches of Sei Whales in the North Pacific. They have only been systematically exploited in this region of the world and this ceased when the IWC's Moratorium on Commercial Whaling was introduced in 1986. Therefore, in comparison with other rorquals, the species had been largely overlooked as a resource and overall, the Bryde's Whale is not believed to be in danger nor at depleted levels.

Fin Whale (Balaenoptera physalus)

The Fin Whale is found throughout every ocean in the world, from the tropics to the polar regions, but is rarely seen inshore. They migrate to polar waters in summer for feeding and return to warmer seas in winter for breeding.

Classification: Linnaeus classified the Fin Whale in 1758, calling it Balaenoptera physalus.

Local Names: Finhval (Norway); Finnhvaler (Iceland); Finnhval (Germany); Finval (Russia); Vinvisch (Netherlands); Finn; Finback; Common Rorqual; Razorback (derived from the sharply ridged tail stock displayed when the whale dives); Finner; Herring Whale.

Description: This is a streamlined whale, second in size to only the Blue Whale. The dorsal fin - which often slopes backwards - is set about two-thirds back along the body, and is not as erect as in the Sei Whale or Minke Whale. The flukes are broad and triangular, and the head is pointed. It is dark-grey to brownish-black in colour, with white undersides and between 55-100 throat grooves. There are 520-950 baleen plates per animal, the largest of which is 90cm in length. The Fin Whale is between 19-22.3m long, with the longest recorded animal at 26m; females are generally larger. It weighs between 45-75 tonnes.

Recognition at Sea: The Fin Whale is almost identical to other rorquals, apart from the fact that it is larger than all others except the Blue Whale. To distinguish between the Fin and the Blue, the Fin’s dorsal appears rapidly after the blow, unlike the Blue’s, which takes longer to appear because of the sheer size of the animal. The Fin Whale's blow is a slim, inverse cone rising about 6m clear of the water.

Food & Feeding: The Fin Whale specialises in 'gulping' euphausiids (tiny plankton), different species of which are preferred in different geographical locations. Some fish, such as herring and capelin, as well as squid, are also taken as food.

Behaviour: Fin Whales are more gregarious in manner than other rorquals, and are usually found either in pairs (as in mother and calf) or in groups of 6-10 animals. Although individuals are also common, congregations of approximately 100 can be found on the feeding grounds. The Fin Whale dives to a maximum of about 300m and communicates via moans, pulses, clicks, and grunts, as well as breaching.

Longevity: Approximately 60 years.

Estimated Current Population: 50-100,000 animals. Vulnerable.

The Influence of Man: When the stocks of Blue Whales became severely depleated from commercial whaling, attention turned to the other rorquals, in particular the Fin Whale. Despite becoming a protected species in the 1976, the damage had already been done: at the peak during the 1950s and 60s, Fin Whale catches were in excess of 30,000 animals per year. It is doubtful that this species will ever recover and return to original population levels.

Humpback Whale (Megaptera novaeangliae)

The Humpback Whale is a widely distributed species, occurring seasonally in all oceans from the Arctic to the Antarctic, with distinct populations located in virtually every sea. All populations of Humpback Whale undertake vast migrations between breeding and feeding grounds, the most famous - and longest - of which is probably made by the Hawaii Humpbacks, who travel to the Bering Strait and Alaska's Glacier Bay every year to feed.

Classification: The Humpback Whale, Megaptera novaeangliae, was classified by German naturalist Borowski, meaning 'Big-Winged New Englander', referring to the size of the whale's huge flippers and one of the first sightings of this species, off New England, America.

Local Names: Baleine à bosse or Megaptère (France); Jorobada (Spain); Knølhval (Norway); Hump-Backed Whale. The common name clearly refers to the species' method of diving, when it lifts its dorsal in such a way as to emphasize the hump before it.

Description: This is a well-known whale, with a stout body and very long flippers that have bumps and lumps upon which barnacles may grow. The head is rounded and flat, apart from the raised lumps ('tubercles') which are also found on the lower jaw. The dorsal fin is varied in size and shape from individual to individual, and tail flukes are large and almost 'wing-shaped'. The Humpback Whale is black to blue-black in colour, with pale to white undersides that can show black markings that are varied according to individual. It is with these markings that individual whales can be indentified. They measure between 12-14m in length, with the females generally larger than the males, and they weigh between 25-30 tonnes. There are 12-36 throat grooves and between 540-800 baleen plates per animal, the longest reaching between 80-100cm.

Recognition at Sea: This is a species that it unmistakable at sea, through the combination of the big, sometimes bushy blow, dark skin colour, the shape of the dorsal, and its habit of raising the flukes on diving. Lobtailing, flipper-slapping and breaching (these whales are very acrobatic) are also other giveaways. As Mark Carwardine said in On The Trail Of The Whale, "look for a giant black cadillac with a radiator problem".

Habitat: The Humpback Whale is found from the topics to the polar waters, and spends a lot of time in much shallower, offshore waters than other rorquals. However, they also cross thousands of kilometres of open ocean when migrating between summer and winter grounds.

Food & Feeding: Humpback Whales tend to feed within 50m of the water's surface, taking krill and shoaling fish such as herring, sandeel, capelin, and mackerel. This is another 'gulping' whale, filtering food from masses of tonnes of water through the baleen plates after engulfing a mouthful. Unlike other rorquals, the Humpback has many varied methods of feeding, including lunge-feeding, tail-flicking and bubble-netting, the latter of which is a favourite subject for nature documentaries. When lunge-feeding, the whale swims through a shoal of its prey with its mouth open, often exploding at the surface with both food and water pouring from the mouth's sides. When tail-flicking, the whale lies in a belly-up position just below the surface with its mouth open, and then flicks its tail clear of the water, casting the prey up into the air and down into its mouth. Bubble-netting, though, is by far the most outstanding. The whale dives beneath a shoal of prey and slowly begins to spiral upwards, blowing bubbles in a circular shape (and emitting a steam-engine sound) as it does so. These bubbles tend to congregate the prey in the centre of the circle, and the ones blown at the bottom of the spiral reach the surface at the same time as the ones blown last. Then the whale returns to beneath the prey, and swims up through the bubble-net into the centre with its mouth open to gulp up all the prey, as shown.

Behaviour: Humpback Whales often congregate in large, loose groups of tens of animals for breeding and feeding, but within these groups they move individually or in the companionship of between 1-3 others. On breeding grounds the well-known 'gentleness' of these animals is abandoned, with males becoming very aggressive as they attempt to claim females for their own. It is with these breeding grounds that the Humpbacks are most commonly associated with their 'singing', which is well-known for being included on the Voyager space mission, along with the golden plaque. The songs can vary from 35 minutes to days in length, with pauses only for breath. It is the males that sing in this fashion. The most acrobatic of large whales, Humpbacks are also well-known for their breaches - one was recorded breaching 200 times in a row - lob-tailing and flipper-slapping. Some Humpbacks in Alaska have been seen rolling over icebergs in play.

Longevity: Approximately 50 years.

Estimated Current Population: 20,000 animals. Vulnerable.

The Influence of Man: Humpbacks were taken on their migrations between their feeding and breeding grounds, as well as on these grounds. Slower, more easily found and less scared than other rorquals, they became a prime target during the modern era of whaling. Between 1900 and 1940, over 100,000 Humpbacks were taken in the Southern Hemisphere alone, with Norther stocks already diminishing. By 1966, however, the species recieved full protection from commercial whaling, although they are still threatened by entrapment in fishing nets. They were brought even further to the forefront of the public's mind with the fourth installment of the Star Trek films, The Voyage Home.

Minke Whale  (Balaenoptera acutorostrata)

The Minke Whale is found from the polar ice-edge to the tropics, and, although mainly an oceanic species, will come quite near to the coast. It does not strictly migrate, but follows its food source.

Classification: Lacépède classified this species as Balaenoptera acutorostrata in 1804. A subspecies was identified by Burmeister in 1867 - Balaenoptera acutorostrata bonaerensis, an inhabitant of the Southern Hemisphere that is distinguishable by the absence of a white band on each flipper.

Local Names: Little Piked Whale; Pike Whale; Little Finner; Lesser Finback; Pikehead; Sharpheaded Finner; Lesser Rorqual. The common name is derived from the Norwegian 'Minkehval'.

Description: The Minke Whale is the smallest of the rorquals, measuring between 8-10m in length and weighing between 8-13.5 tonnes. It is stocky but slender, with a small, narrow triangular head and pointed, paddle-like flippers. The dorsal is relatively tall, and is set about two thirds of the way along the back. The body colour is dark slate grey, with paler grey to white on the undersides and throat, on which there are between 50-70 grooves. Each flipper usually bears a bright white band which is noticably absent in the subsecies, Balaenoptera acutorostrata bonaerensis. There are between 460-720 baleen plates per animal, the longest of which is 30cm in length.

Recognition at Sea: This is an inquistive cetacean, unlike the other rorquals, and will frequently approach and linger around ships. This behaviour and the whale's small size make it easy to identify. The blow is about 2-3m high and can only be seen in good weather.

Habitat: This species is found both inshore and offshore, in waters both polar, tropical and temperate.

Food & Feeding: Minke Whales seem to feed very little in warm waters. In both the Northern and Southern Hemisphere, the preferred diet is euphausiids, though those in the former will also take shoaling fish and small free-swimming molluscs.

Behaviour: Minke Whales regularly occur either in groups of 2-3 or as individuals, with large congregations amassing on feeding grounds. The whale communicates via grunts, clicks, pulses and breaching.

Longevity: Approximately 60 years.

Estimated Current Population: 610,000 - 1,284,000 animals.

The Influence of Man: This species was never considered commercially or economically worthwhile until the 1970s, until large catches were taken in the Antarctic by Japan and the Former Soviet Union. When the IWC's Moratorium on Commercial Whaling came into effect in 1986, only catches under scientific permit have been allowed, chiefly by Japan and Norway. However, despite this 'scientific permit', the meat from these whales - and many other species - still ends up on many butchers' slabs.

Sei Whale (Balaenoptera borealis)

The Sei Whale is found in virtually every ocean and sea in the world. However, it does not like extreme environments and is less likely to be found in polar waters than other rorquals. The subarctic and subantarctic are favoured for summer feeding, but the majority of Sei Whales are found in temperate and sub-tropical waters, and migrations between these areas are annual.

Classification: The Sei Whale was classified in 1828 by the French zoologist René Lesson, who named it Balaenoptera borealis (referring to the north).

Local Names: Coalfish Whale; Pollack Whale; Rudolphi's Rorqual; Sardine Whale; Japan Finner. The name 'Sei' refers to the whales' habit of arriving off the northern Norwegian coast with the seje (coalfish).

Description: This is a slender cetacean, although more robust than the Fin Whale. The dorsal fin is well-defined and slightly hooked and is located about two-thirds back along the body. The head and jaws are rather narrow and slightly arched, unlike in other rorquals. It is a mottled dark grey in colour, with paler undersides and between 38-60 throat grooves. There are 636-680 dark baleen plates per animal, the longest of which is 78cm. The Sei Whale is between 13.6-16m long, with the longest recorded animal at 18.3m; females are generally larger than males. It weighs between 20-25 tonnes.

Recognition at Sea: The shape of the head and the poition of the dorsal (which is clearly visible on blowing ) distinguish the Sei Whale from other rorquals. The blow is a vertical, moderately tall 'cloud'.

Habitat: This species is essentially a dweller of the open ocean, not generally found inshore or in coastal waters. The Sei Whale tends to follow shelf contours and plankton gatherings.

Food & Feeding:The Sei Whale will take whatever is in abundance locally, whether it be fish (upto 30cm long), squid or plankton, as long as it is shoaling. It swims on one side through the shoaling fish and then filters out the water with its baleen plates and tongue.

Behaviour: Sei Whales tend to swim in pods of 3-5 animals, and rarely dive deeper than 300m. Although little is known about how this species communicates, it has been found that low-frequency pulses are common.

Longevity: Approximately 70 years.

Estimated Current Population: 65,000 animals. Vulnerable.

The Influence of Man: The Sei Whale was not traditionally a target for whalers because it lived in the same waters as Blue, Fin and Humpback Whales, which were the preferred quarry. However, when these stocks began to decline and then became protected, Sei Whales became the primary catch from the mid-1960s onwards. By the mid-1970s, the Sei Whale stocks were 'fished out' and the species earned protected status in 1979.

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