This paper describes the growth and development of the sealing industry of northern Norway from 1859 to 1909 and is based largely on hunting returns and shipping records of the Tromsø fleet. Arctic hunting operations displayed remarkable diversity across the years and the ascendancy of sealing only emerged towards the end of the 19th century. The paper shows how the fleet increased in size despite the lack of capital in northern Norway for investment in new vessels and how hunting grew in significance as a commercial operation following the introduction of modern hunting techniques and better weapons. The fleet increased almost eightfold, from 6 vessels in 1859 to 46 in 1909 while the harvest of seals increased from less than 1500 to over 30000 animals annually. The geographical range of the hunting grounds expanded correspondingly from a limited area around Jan Mayen and the west coast of Spitsbergen to a huge area which included the western ice (north and south of Jan Mayen), the northern ice (Svalbard), the eastern ice (Kola Peninsula to Novaya Zemlya, the White Sea), Zemlya Frantsa-Isoifa [Franz Joseph Land], the Denmark Strait and northeast Greenland. The species composition of the harvest underwent a remarkable series of transitions, one species being replaced by another as local stocks became successively depleted. Thus, it was dominated numerically first by Svalbard reindeer and walrus, then beluga whales and then cod before finally consisting largely of polar bears, bottlenose whales and seals. Owners and skippers responded to reductions in numbers by searching for new hunting grounds and, in doing so, sailed further north, then east and then west than ever before, coincidentally making a series of historical voyages of discovery. By the end of these five decades sloops had largely been replaced by ketch rigged diesel sealers, these being an assortment of new, salvaged and second hand foreign ships.