Jumbo squid in the eastern Pacific Ocean: A quarter century of challenges and change

The jumbo, or Humboldt, squid Dosidicus gigas currently accounts for about one third of total world squid landings ( Arkhipkin et al., 2015). It is the largest and most abundant ommastrephid squid in the eastern Pacific, where it is endemic. It is an important predator throughout its geographical range ( Markaida, 2006, Field et al., 2013 and Alegre et al., 2014) and is prey for large marine mammals, particularly sperm whales in the southeastern Pacific, for which it is the single most important food species ( Clarke et al., 1988 and Nigmatullin et al., 2001). The large-scale fishery for D. gigas began in the 1980s in the Mexican northeast Pacific ( Ehrhardt et al., 1983) and this was followed in the 1990s in Peruvians waters of the southeast Pacific (Yamashiro et al., 1998). Annual catches increased from 19,000 t in the 1980s to 847,000 t in 2013 (ftp://ftp.fao.org/FI/STAT/summary/inicio.htm). It became one of the largest marine invertebrate fisheries in the world, and the first Peruvian fishery to be fully monitored by observers at sea in the Peruvian EEZ and at ports where landings are made (Guevara-Carrasco et al., 2015). During this period D. gigas has shown significant changes in abundance, distribution and population structure in both the northeast and southeast Pacific. These have been associated with (1) direct effects of environmental variability, (2) changes in the availability of prey, especially during the early ontogenetic stages, (3) changes in predation, disease and parasitism, and (4) possible reduction of natural mortality through the exploitation of their predators as suggested by Rodhouse (2008). The development of an artisanal fishery in Peruvian waters (2350 artisanal boats with an average capacity of 9.8 tons) and in Chilean waters, as well as an industrial fishery outside the Peruvian and Chilean EEZs (Chen et al., 2008) have taken place against the background of these changes

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