 Modern whaling was more efficient than open @-@ boat whaling , employing steam @-@ powered ships and exploding harpoons . Initially , modern whaling activity focused on large baleen whales , but as these populations were taken , sperm whaling increased . Spermaceti , the fine waxy oil produced by sperm whales , was in high demand . In both the 1941 to 1942 and 1942 to 1943 seasons , Norwegian expeditions took over 3 @,@ 000 sperm whales off the coast of Peru alone . After the war , whaling continued unabated to obtain oil for cosmetics and high @-@ performance machinery , such as automobile transmissions . 
