First Humpback Whale Movement Between Ecuador and the South Sandwich Islands: Redefines the Easternmost Migration Point of Breeding Stock G

Abstract

The humpback whales ( Megaptera novaean-gliae ) of the Southern Hemisphere migrate long distances from their feeding grounds in Antarctic waters to the tropics (Matthews, 1937). At the end of the feeding season, each population (i.e., stock) migrates latitudinally towards the Equator to its own coastal or insular breeding ground in tropical or near-tropical waters. Seven humpback whale breeding stocks (A to G) and six management feeding areas (Areas I to VI) are recognized by the International Whaling Commission (IWC) (1998). Two breeding populations migrate along South America: Breeding Stock A is found in the coastal waters of Brazil, and Breeding Stock G is found on the west coast of South America from northern Peru to south Nicaragua (Pacheco et al., 2009; IWC, 2011; De Weerdt et al., 2020). These populations feed in two Antarctic management areas. Feeding Area I goes from 120° to 60° W (IWC, 2005). South Georgia ( ∼ 54° S, 36° W) and the South Sandwich Islands ( ∼ 58° S, 26° W) in the Scotia Sea, South Atlantic (Feeding Area II), are known feeding grounds for Breeding Stock A (Stevick et al., 2006; Zerbini et al., 2006, 2020; Engel et al., 2008; Engel & Martin, 2009; Marcondes et al., 2021), whereas the western Antarctic Peninsula (Feeding Area I)