South!, Ernest Shackleton [good books to read in english TXT] 📗

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 subtropics. 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 Euphausiae were taken in the hauls⁠—though sparingly. During the winter spent at Elephant Island, our total catch of gentoo penguins amounted to 1,436 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 Euphausiae 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. Euphausiae, 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 foetal records, which show the pairing takes place in the northern areas, that the foetus 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
(Balaenidae)

Rorquals
(Balaenopteridae)

Southern right whale
(Balaena glacialis)

Finner whales (Balaenoptera)

Humpback
(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
(Physeter catodon)

Beaked whales (including bottlenose whales)
(Hyperoodon rostratus)

Dolphins

(1) Killer
(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 lamellae 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—Euphausiae, 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