From South Georgia the track of the Endurance lay in a direct line to the South Sandwich Group, between Saunders and Candlemas Islands. Then south-easterly and southerly courses were steered to the Coats’ Land barrier, along which we steamed for a few hundred miles until forced westward, when we were unfortunately held up in about lat. 76° 34´ S. and long. 37° 30´ W. on January 19, 1915, by enormous masses of heavy pack-ice. The ship drifted to lat. 76° 59´ S., long. 37° 47´ W. on March 19, 1915, and then west and north until crushed in lat. 69° 5´ S. and long. 51° 30´ W. on October 26, 1915. We continued drifting gradually north, afloat on ice-floes, past Graham Land and Joinville Island, and finally took to the boats on April 9, 1916, and reached Elephant Island on April 15. The Falkland Island Dependencies were thus practically circumnavigated, and it may be interesting to compare the records of whales seen in the region outside and to the south of this area with the records and the percentage of each species captured in the intensive fishing area.
The most productive part of the South Atlantic lies south of latitude 50° S., where active operations extend to and even beyond the Antarctic circle. It appears to be the general rule in Antarctic waters that whales are more numerous the closer the association with ice conditions, and there seems to be reasonable grounds for supposing that this may explain the comparatively few whales sighted by Expeditions which have explored the more northerly and more open seas, while the whalers themselves have even asserted that their poor seasons have nearly always coincided with the absence of ice, or with poor ice conditions. At all events, those Expeditions which have penetrated far south and well into the pack-ice have, without exception, reported the presence of whales in large numbers, even in the farthest south latitudes, so that our knowledge of the occurrence of whales in the Antarctic has been largely derived from these Expeditions, whose main object was either the discovery of new land or the Pole itself. The largest number of Antarctic Expeditions has concentrated on the two areas of the South Atlantic and the Ross Sea, and the records of the 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: