Distribution, hand embroidered on undyed calico.

The main aim of the Discovery Oceanographic Expedition (1924-27) was to investigate the sustainability of the South Atlantic Whale Fishery.  As part of this there needed to be an understanding of the marine ecosystem that sustained the whales. It was known that krill (mostly Antarctic Krill Euphausia superba) were the main food source for these whales but it was not clear how whales could catch enough of these small crustaceans to meet their nutritional needs.  They discovered that krill populations are not uniformly distributed (as once thought) but that they can occur in huge, dense patches.  This illustration, taken from the Discovery Reports showed for one of the first times that the presence of whales (by location of whales caught by the whalers) was linked to locations of these large populations of krill at the same time.