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The Whales of the Cape |
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See the 2004 WHALE REPORT
24 May 2004 – 30 November 2004 Several species of whale come into False Bay and can be seen in the vicinity of Simon's Town. These include Bryde's Whale, the Humpback Whale (which is the one that 'sings') and the Killer Whale, more commonly known as the Orca. By far the most common, however, is the Southern Right Whale.
 Scientific Name And Statistics
Description
The term "right"
whale refers to the fact that in the nineteenth century these whales
were regarded as the "right" whales to catch, because
they were particularly rich in oil, being slow swimmers they were
easy to catch, and because their carcases were easy to handle as
they floated when dead. It is usually considered that there are
two species of "right" whales, one in the northern hemisphere
and the other in the southern hemisphere.
Southern right whales are baleen whales. This mean that they have about 200 to 270 pairs of fine 'plates' which hang down from the upper jaw like vertical venetian blinds, through which they filter their food [see under Diet]. These plates may be up to 3 metres (9.5 feet) long. The most striking feature of the Southern Right whales are the 'callosities' (horny growths) behind the blowholes, and on the face. These provide homes for several other creatures, including the 'whale lice' or cyamids, which live on the callosities and operate in a symbiotic relationship with the whales, feeding off the dead skin. Barnacles, called Tubercinella Major, burrow 4 cm down into the skin. The other characteristic which distinguishes the Southern Right whales are their V-shaped blows. Southern Right whales are black or dark grey in colour. They have no dorsal fin. They have a large, bow-shaped heads and arched mouths. Unusually, Southern Right whales are relatively hairy with up to 300 hairs on the tip of the lower jaw and about 100 on the upper jaw. Southern Right whales can remain under water for about 6 minutes and swim fairly slowly at an average speed of 6 kilometres and hour when cruising, although than can reach 11 kilometres an hour in short bursts. Although the humpback whales are the best "singers", Southern Rights do produce low frequency sounds to communicate with one another. The lifespan of the Southern Right whale is not established, but it is believed that they can live for over 50 years.
 Range
& Habitat The Southern Right Whale
lives between latitudes 20° to 55°, occasionally venturing
down to 63°. Although it is to be found throughout the southern
oceans, in our part of the world it returns annually to the sheltered
bays of the Southern African coast in order to breed and give birth.
In False Bay it can be seen between June and November. It is most
prolific close to the shore from about September, and it is occasionally
seen out of season, as early as May or as late as January.
During the summer months the southern right whales move south to the cold and stormy waters of the Antarctic where it feeds. Diet
As baleen whales, right whales
swim with their mouths open so that the baleen plates can filter
out the water and retain the krill forms a large part of their diet.
They eat up to 1½ tons a day of these tiny creatures. They
are seasonal feeders, eating in winter and living off their blubber
in the breeding months in the north.
Reproduction
One female southern right
whale will mate with a number of males at the same time, with sometimes
as many as eight competing for her favour. The male producing the
most sperm is probably the father of her baby. Females usually have
one calf every three years.
The gestation period (pregnancy) of the southern right is twelve months, she bears her calf in the spring in the warmer waters of southern African bays. Usually only one calf is born although twins sometimes occur. About 3% of calves are born white, but this usually becomes grey after a few months. The calf is born tail first and immediately swims to the surface of the water to take its first breath. Initially it is helped by the mother but within thirty minutes of birth it can swim. The newborn calf is about 4,5 to 5 metres long. The calf suckles from a pair of teats, sometimes consuming 600 litres of milk a day and growing 2,8 cm a day. It is weaned after about 6-8 months by which time it has reached about 9 metres in length. Conservation
Southern right whales
are regarded as an endangered species as their numbers have been
considerably reduced in the last 200 years. Between 1790 and 1825
it is estimated that over 12 000 southern rights were killed by
whalers of the South African coast. Now collisions with ships or
entanglement in fishing gear are the main dangers. There are now
about 4500 southern right whales, with about 1500 coming to southern
Africa. However, southern rights are not as vulnerable as the northern
rights which are believed to be close to extinction since they live
in more hazardous waters. Moreover, southern rights are increasing
in number, doubling in size every ten years, which means that they
should have returned to their optimum population size in about 2040.
In 1980 and again in 1984 legislation was introduced in South Africa to protect whales. It is now illegal to shoot at whales, or harass them by coming closer than 300 metres in any craft.
Scientific Name And Statistics
Description
Bryde's whales are distinguised
by their prominent "falcate" dorsal fins. They are rorqual
whales. This means that they have throat grooves which enable them
to open their mouths very wide in order engulf great quantities
of water when feeding. However, they are distinguished by three
ridges running along the top jaw. The upper body is dark grey, lightening
under the belly, becoming white in the centre. There is a slate-grey
band across the underside of the body at the end of the throat grooves.
Range
& Habitat Bryde's whales may be
seen along the whole length of the South African coast at any time
of the year. However, they are most visible when shoals of small
fish are plentiful inshore or in False Bay.
Relatively little is known about Bryde's whales. There seem to be two populations along the South African coast, one of which is "resident" (non-migratory) in inshore, shallow waters, including False Bay. They are usually seen singly although sometimes small groups from when they are feeding. They are not particularly fast swimmers, nor do they dive deeply, usually remaining under water for a only couple of minutes. Diet
Bryde's whales feed on large
shoals of small fish like pilchards and sardines, in the company
of gannets, penguins and dolphins. They zig-zag through the water
on their sides, gulping food as they go.
Reproduction
Little is known of the
reproduction of Bryde's whales.
Conservation
Bryde's whales have not been
exploited much by whalers, and as a result, as far as we know, there
has not been a serious depletion of their population.
Scientific Name And Statistics
 Description
The Humpback whale is
distinguished particularly by its very long flippers which are almost
a third of its body length and is white in colour. The body is black,
although it may have white patches, and is fairly short and round.
It has a large head on which there are three irregular rows of knobs
(tubercules). There are similar projections on each side of the
lower jaw, at the tip of which there is a large, rough, wart-like
area. Like the Bryde's whales, they are rorqual whales with throat
grooves running from the chin to the navel. The dorsal fin is fairly
short and thick, set on the long, sloping hump which gives the whale
its name. There are two blowholes.
The male humpback whale is particularly notable for the wide range of sounds it produces - moans and screams of varied pitch, lasting up to 30 minutes, and ranging from 20 to 9000 Hertz (females don't sing!) These "songs" differ according to locality and the patterns appear to change from year to year, but seem to occur only in warm waters. It is believed that they are some form of communication. Humpback whales are the acrobats of the ocean, "breaching" (jumping clear of the water) and "lobtailing" (slapping the water with their tails). They also "spyhop" (poke their heads out of the water). They usually occur singly or in small groups (pods). They remain submerged for about 15 minutes, diving to depths of 150 to 210 metres (500 to 700 feet). Their swimming speed is about 12 kilometres an hour (3 to 9 miles an hour), although speeds of up to 25 kilometres (15 to 16 miles) an hour have been recorded. Range
& Habitat Humpback whales are to be found
all round the Southern African coast but the two main pods are located
off the Angolan and Mozambique coasts. They migrate north in the
winter, to mate and breed, largely off the east African coast, with
their numbers peaking in June and July.
 Diet
Humpback whales, like
other baleen whales, seem to be seasonal feeders but they do eat
copepods and fish off the Angolan coast. On average a Humpback whale
eats 2000-2500 kilograms of food a day during the feeding season.
They co-operate in hunting, rounding up their prey in "bubble-nets".
A hunting pod forms a circle under water, then blows a wall of bubbles
as it swims to the surface in a spiral path. This cylindrical wall
of bubbles traps the prey which the humpbacks devour as they all
(whales and prey) move to the surface.
Reproduction
Humpback whales form only
temporary relationships. Females reach sexual maturity when they
are about 15 years old and they bear a calf about every three years.
The spectacular activities of the humpback whales, breaching and
lobtailing, are believed to be courtship rituals. Gestation lasts
about a year, with the female giving birth to a single calf, although
twins do occur. The calves are about 4,2 metres long when they are
born, and they are suckled for about 10 to 11 months. Humpback whales
reach puberty after 4 to 7 years.
Conservation
Because they occur close
to the coast and swim fairly slowly, humpback whales have suffered
severely from modern whaling. It is estimated that there are about
10 000 to 15 000 whales throughout the world. In South
Africa 1963 they received full protection and their numbers do now
seem to be increasing.
Scientific Name And Statistics
 Description
Orcas are the largest
dolphins. They have a short, rounded head with a very short beak
containing 10 to13 large conical teeth in each jaw. The flippers
are broad and well-rounded at the tips. Their dorsal fins get larger
as they grow older, and are their most distinguishing characteristic,
sometimes reaching 2 metres high in mature males. They have broad
flukes (tails) and the upper parts of their bodies are dark, black
to brown, while the lower jaws and bellies are white. Behind the
eyes there are oval white patches, and others behind the dorsal
fins.
Like all dolphins, orcas produce whistling and clicking sounds. It is thought that the whistling is used for communication with other group members, and the clicks for 'echolocating' prey. The effect that the sounds have on other marine animals is dramatic, prompting whales and other dolphins to flee the area, and penguins and seals to head as quickly as they can for land. Range
& Habitat Orcas may be found the
whole length of the South African coast, including False Bay, but
their movements are unpredictable. Little is known of their migratory
patterns.
Orcas sometimes form groups of up to 200 animals but in the South African waters they are usually in small groups of 3 or 4. They can attain speeds of up to 30 kilometres and hour and dive for up to 6 or 7 minutes. Diet
Orcas have a varied diet,
ranging from fish, squid, and sea birds to seals, dolphins and small
whales. They have a fearsome reputation as killers and seals appear
to have an inborn fear of them. Orca packs appear to disable their
mammalian prey by biting the flippers or flukes and then attempt
to get to the tongue, which they like particularly. One report claims
that the remains of 14 seals and 13 porpoises were found in the
stomach of one orca!
Despite their fearsome reputations, there are no records of orcas attacking man. In captivity they are docile and respond well to training. Reproduction
In tropical waters orcas seem
to mate and calve throughout the year, but in cooler waters these
activities are confined to summer. The gestation period is about
a year. Calves are about 2.3 metres long at birth and are suckled
for about twelve months. Orcas reach sexual maturity at about 12
years of age, when they are about 5 metres long.
Conservation
It is not known how vulnerable
orcas are, although it is suspected that they are endangered.
Organisations Concerned With The Preservation & Protection Of Whales DOLPHIN
ACTION & PROTECTION GROUP This organisation was a pioneer
in South Africa in working for the protection of the marine mammals
off our coasts. They can be contacted at:
MARINE
AND COASTAL MANAGEMENT Travelogue on The Real Whale Capital Whale
sightings log for False Bay and Map
Further
Reading
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