Biomass removal from shore-based whaling in the Azores

Knowledge on historical fisheries removal is essential for adopting an ecosystem approach to the management of marine resources. Shore-based whaling was an important economic activity for the Azores archipelago with 23,557 sperm whales (Physeter macrocephalus) captured between 1896 and 1987. The corresponding biomass is unknown because local official fisheries statistics report this extractive component in number of sperm whales and total oil production. The objective of this study was to estimate total sperm whale biomass removed during shore-based whaling operations using two different methods: (1) a function of length of males and females and (2) a function of oil extraction efficiency. The estimated sperm whale biomass removed from Azorean waters by shore-based whalers between 1896 and 1987 was 361,039 tonnes (250,297-619,561 tonnes). For the period 1950-1987, sperm whale catches represented 29% of the total biomass removed by fisheries, including whaling. At the peak of whaling activity (1950-1957), sperm whale catches were about twice the amount reported by the fisheries sector. The results show that biomass removal by whaling was important in the scope of the regional fisheries. Consequently, including sperm whale biomass extractions into the total marine fisheries catch for the Azores is of high relevance for implementing an ecosystem approach to management. (C) 2013 Elsevier B.V. All rights reserved.