Page:South - the story of Shackleton's last expedition, 1914-1917.djvu/489

Rh 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 packice. 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 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 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 subAntarctic 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: