Vertical migratory behavior of jumbo flying squid (Dosidicus gigas) off Peru: Records of acoustic and pop-up tags

Abstract

The vertical migratory behavior of jumbo flying squid (Dosidicus gigas) was recorded in the Humboldt Current region off Peru in 2007 by ship-based tracking with acoustic tags for two days and a pop-up archival transmitting (PAT) tag for two weeks. Two squid (measuring 74.0 cm and 110.5 cm in dorsal mantle length, respectively) were tagged with acoustic tags. The larger one was also tagged with a PAT tag. Tracking data indicated that both squid dived to a depth of 1200 m in the daytime. Although the PAT tag was not recovered, its seven-day summary data that was recovered via the Argos satellite system suggest that D. gigas off Peru engage in diel vertical migration, where the squid also migrate to near the sea surface at night. Conversely, two daytime migration patterns were observed: migration to mid-waters above the oxygen minimum zone (OMZ) at depths between 200 and 800 m, and migration to deeper waters. During descents to 1200 m, the squid increased its descending velocity in the OMZ. We also discuss the biological implications of that diel vertical migration.