South: The Story of Shackleton's Last Expedition, 1914-1917
occurrences of whales have, in consequence, been concentrated in these
two localities. In the intervening areas, however, Expeditions, notably
the _Belgica_ on the western side and the _Gauss_ on the eastern side
of the Antarctic continent, have reported whales in moderately large
numbers, so that the stock is by no means confined to the two areas
above mentioned.
The effective fishing area may be assumed to lie within a radius of a
hundred miles from each shore station and floating-factory anchorage,
and a rough estimate of all the Falkland stations works out at 160,000
square miles. The total for the whole Falkland area is about 2,000,000
square miles, which is roughly less than a sixth of the total Antarctic
sea area. The question then arises as to how far the “catch percentage”
during the short fishing season affects the total stock, but so far one
can only conjecture as to the actual results from a comparison of the
numbers seen, chiefly by scientific and other Expeditions, in areas
outside the intensive fishing area with the numbers and percentage of
each species captured in the intensive fishing area. Sufficient
evidence, however, seems to point quite definitely to one species—the
humpback—being in danger of extermination, but the blue and fin
whales—the other two species of rorquals which form the bulk of the
captures—appear to be as frequent now as they have ever been.
The whales captured at the various whaling-stations of the Falkland
area are confined largely to three species—blue whale (_Balænoptera
musculus_), fin whale (_Balænoptera physalis_), and humpback
(_Megaptera nodosa_); sperm whales (_Physeter catodon_) and right
whales (_Balæna glacialis_) being only occasional and rare captures,
while the sei whale (_Balænoptera borealis_) appeared in the captures
at South Georgia in 1913, and now forms a large percentage of the
captures at the Falkland Islands. During the earlier years of whaling
at South Georgia, and up to the fishing season 1910–11, humpbacks
formed practically the total catch. In 1912–13 the following were the
percentages for the three rorquals in the captures at South Georgia and
South Shetlands:
Humpback 38 per cent., fin whale 36 per cent., blue whale 20 per cent.
Of late years the percentages have altered considerably, blue whales
and fin whales predominating, humpbacks decreasing rapidly. In 1915,
the South Georgia Whaling Company (Messrs. Salvesen, Leith) captured
1085 whales, consisting of 15 per cent. humpback, 25 per cent. fin
whales, 58 per cent. blue whales, and 2 right whales. In the same year
the captures of three companies at the South Shetlands gave 1512
whales, and the percentages worked out at 12 per cent. humpbacks, 42
per cent. fin whales, and 45 per cent. blue whales. In 1919, the
Southern Whaling and Sealing Company captured (at Stromness, South
Georgia) 529 whales, of which 2 per cent. were humpbacks, 51 per cent.
fin whales, and 45 per cent. blue whales. These captures do not
represent the total catch, but are sufficiently reliable to show how
the species are affected. The reduction in numbers of the humpback is
very noticeable, and even allowing for the possible increase in size of
gear for the capture of the larger and more lucrative blue and fin
whales, there is sufficient evidence to warrant the fears that the
humpback stock is threatened with extinction.
In the immediate northern areas—in the region from latitude 50° S.
northward to the equator, which is regarded as next in importance
quantitatively to the sub-Antarctic, though nothing like being so
productive, the captures are useful for a comparative study in
distribution. At Saldanha Bay, Cape Colony, in 1912, 131 whales were
captured and the percentages were as follows: 35 per cent. humpback, 13
per cent. fin whale, 4 per cent. blue whale, 46 per cent. sei whale,
while nearer the equator, at Port Alexander, the total capture was 322
whales, and the percentages gave 98 per cent. humpback, and only 2
captures each of fin and sei whales. In 1914, at South Africa (chiefly
Saldanha Bay and Durban), out of a total of 839 whales 60 per cent.
were humpback, 25 per cent. fin whales, and 13 per cent. blue whales.
In 1916, out of a total of 853 whales 10 per cent. were humpback, 13
per cent. fin whales, 6 per cent. blue whales, 68 per cent. sperm
whales, and 1 per cent. sei whales. In Chilian waters, in 1916, a total
of 327 whales gave 31 per cent. humpbacks, 24 per cent. fin whales, 26
per cent. blue whales, 12 per cent. sperm whales, and 5 right whales.
There seems then to be a definite interrelation between the two areas.
The same species of whales are captured, and the periods of capture
alternate with perfect regularity, the fishing season occurring from
the end of November to April in the sub-Antarctic and from May to
November in the sub-tropics. A few of the companies, however, carry on
operations to a limited extent at South Georgia and at the Falkland
islands during the southern winter, but the fishing is by no means a
profitable undertaking, though proving the presence of whales in this
area during the winter months.
The migrations of whales are influenced by two causes:
(1) The distribution of their food-supply;
(2) The position of their breeding-grounds.
In the Antarctic, during the summer months, there is present in the sea
an abundance of plant and animal life, and whales which feed on the
small _plankton_ organisms are correspondingly numerous, but in winter
this state of things is reversed, and whales are poorly represented or
absent, at least in the higher latitudes. During the drift of the
_Endurance_ samples of _plankton_ were taken almost daily during an
Antarctic summer and winter. From December to March, a few minutes haul
of a tow-net at the surface was sufficient to choke up the meshes with
the plant and animal life, but this abundance of surface life broke off
abruptly in April, and subsequent hauls contained very small organisms
until the return of daylight and the opening up of the pack-ice. The
lower water strata, down to about 100 fathoms, were only a little more
productive, and _Euphausiæ_ were taken in the hauls—though sparingly.
During the winter spent at Elephant Island, our total catch of gentoo
penguins amounted to 1436 for the period April 15 to August 30, 1916.
All these birds were cut up, the livers and hearts were extracted for
food, and the skins were used as fuel. At the same time the stomachs
were invariably examined, and a record kept of the contents. The
largest proportion of these contained the small crustacean _Euphausia_,
and this generally to the exclusion of other forms. Occasionally,
however, small fish were recorded. The quantity of _Euphausiæ_ present
in most of the stomachs was enormous for the size of the birds. These
penguins were migrating, and came ashore only when the bays were clear
of ice, as there were several periods of fourteen consecutive days when
the bays and the surrounding sea were covered over with a thick compact
mass of ice-floes, and then penguins were entirely absent.
_Euphausiæ_, then, seem to be present in sufficient quantity in
certain, if not in all, sub-Antarctic waters during the southern
winter. We may assume then that the migration to the south, during the
Antarctic summer, is definitely in search of food. Observations have
proved the existence of a northern migration, and it seems highly
improbable that this should also be in search of food, but rather for
breeding purposes, and it seems that the whales select the more
temperate regions for the bringing forth of their young. This view is
strengthened by the statistical fœtal records, which show the pairing
takes place in the northern areas, that the fœtus is carried by the
mother during the southern migration to the Antarctic, and that the
calves are born in the more congenial waters north of the sub-Antarctic
area. We have still to prove, however, the possibility of a circumpolar
migration, and we are quite in the dark as to the number of whales that
remain in sub-Antarctic areas during the Southern winter.
The following is a rough classification of whales, with special
reference to those known to occur in the South Atlantic:
1. WHALEBONE WHALES (_Mystacoceti_)
____________________|__________________
Right whales (_Balænidæ_) Rorquals (_Balænopteridæ_)
| ________________|_________
Southern right whale | | (_Balæna
glacialis_) Finner whales Humpback
(_Balænoptera_) (_Megaptera nodosa_)
Blue whale (_B. musculus_) Fin whale (_B.
physalis_) Sei whale (_B. borealis_) Piked
whale (_B. acutorostrata_) Bryde’s whale (_B.
brydei_)
2. TOOTHED WHALES (_Odontoceti_)
_________________________|________________________
Sperm whale Beaked whales Dolphins (_Physeter
catodon_) (including bottlenose whales) (1) Killer (_Hyperoodon
rostratus_) (_Orcinus orca_) (2) Black Fish (_Globicephalus melas_)
(3) Porpoises (_Lagenorhynchus_ sp.)
The subdivision of whalebone whales is one of degree in the size of the
whalebone. These whales have enormously muscular tongues, which press
the water through the whalebone lamellæ and thus, by a filtering
process, retain the small food organisms. The food of the whalebone
whales is largely the small crustacea which occur in the _plankton_,
though some whales (humpback, fin whales, and sei whales) feed also on
fish. The stomachs examined at South Georgia during December 1914,
belonged to the three species, humpbacks, fin whales, and blue whales,
and all contained small crustacea—_Euphausiæ_, with a mixture of
_amphipods_. The toothed whales—sperms and bottlenoses—are known to
live on squids, and that there is an abundance of this type of food in
the Weddell Sea was proved by an examination of penguin and seal
stomachs. Emperor penguins (and hundreds of these were examined) were
invariably found to contain _Cephalopod_ “beaks,” while large, partly
digested squids were often observed in Weddell seals. A dorsal fin is
present in the rorquals but absent in right whales. With other
characters, notably the size of the animal, it serves as a ready mark
of identification, but is occasionally confusing owing to the variation
in shape in some of the species.
With the exception of several schools of porpoises very few whales were
seen during the outward voyage. Not till we approached the Falkland
area did they appear in any numbers. Four small schools of fin whales
and a few humpbacks were sighted on October 28 and 29, 1914, in lat.
38° 01´ S., long. 55° 03´ W. and in lat. 40° 35´ S., long. 53° 11´ W.,
while _Globicephalus melas_ was seen only once, in lat. 45° 17´ S.,
long. 48° 58´ W., on October 31, 1914. At South Georgia, the whales
captured at the various stations in December 1914, were blue whales,
fin whales, and humpbacks (arranged respectively according to numbers
captured). During the fishing season 1914–15 (from December to March)
in the area covered—South Georgia to the South Sandwich Islands and
along Coats’ Land to the head of the Weddell Sea—the records of whales
were by no means numerous. Two records only could with certainty be
assigned to the humpback, and these were in the neighbourhood of the
South Sandwich Islands. Pack-ice was entered in lat. 59° 55´ S., long.
18° 28´ W., and blue whales were recorded daily until about 65° S.
Between lat. 65° 43´ S., long. 17° 30´ W., on December 27, 1914, and
lat. 69° 59´ S., long. 17° 31´ W., on January 3, 1915, no whales were
seen. On January 4, however, in lat. 69° 59´ S., long. 17° 36´ W., two