The SOWER programme in the Antarctic : background, aims and objectives

Abstract

The International Whaling Commission (IWC) imposed limits on the catch of Antarctic minke whales close to the start of commercial whaling in the 1970s. These management efforts were hampered by the challenge of obtaining robust estimates of population size. Contemporary whale assessments largely relied on measuring changes in availability as a result of exploitation – usually catch per unit effort (CPUE). However, this approach was largely impractical for Antarctic minke whales due to: (a) the short time series of CPUE data; (b) the setting of relatively conservative catch limits, so that changes in CPUE due to exploitation were difficult to detect; and (c) the possibility that abundance had been increasing before this time due to over‐exploitation of other baleen whales. The IWC initiated a series of assessment cruises in 1978 designed to obtain abundance estimates for targeted management areas in the Antarctic. Designed by the IWC’s Scientific Committee, these cruises were independent of whaling operations. The vessels were chartered whale catchers provided by Japan for the duration of the programme – and by the Soviet Union for a period of seven years. With the eventual participation of 86 scientists from 16 IWC member states, this programme became a key part of the International Decade of Cetacean Research (IDCR), launched in 1975 as a response to the 1972 Stockholm Resolution that called for a 10‐year moratorium on commercial whaling and the intensification of research efforts. While originally planned as ‘Discovery’ marking and sighting cruises, the programme eventually relied almost exclusively on sighting methods. Lasting over 30 years and involving three circumnavigations of the Southern Ocean, it became one of the largest whale monitoring exercises ever undertaken.