Marine predator migration during range expansion: Humboldt squid Dosidicus gigas in the northern California Current System

Abstract

Humboldt squid Dosidicus gigas have undergone a major range expansion in the northern California Current System (CCS) during the last decade. These squid are thought to migrate annually from Mexican waters into the CCS where they prey on many species, including several that support lucrative fisheries; however, swimming capabilities and features of longdistance horizontal migrations are not well understood. In the present study, adult Humboldt squid were tagged off central California with pop-up archival transmitting (PAT) tags (n = 5). All squid ex hibited diel vertical migrations and swam south or offshore (west) during tag deployment (2.7 to 17.6 d). One squid swam south at least 34 km d −1 for >17 d and crossed into Mexican waters, which is the highest sustained velocity and the longest horizontal migration observed thus far for Humboldt squid. Results from a simple model to estimate the daily locations and velocities of each squid throughout the deployments suggest an average velocity of ~37 km d −1 and a maximum of 50 km d −1. Additionally, the model suggests that one squid made a bidirectional movement (first north and then returning south) that was not evident from deployment and pop-up positions alone. This study provides insight into Humboldt squid migratory capabilities that are relevant to seasonal migrations and episodic range expansions, both of which are crucial to future interactions of this species with ecosystems and fisheries.KEY WORDS: California Current System · Jumbo squid · Range expansion · Satellite tagging · Swimming velocity Resale or republication not permitted without written consent of the publisher

Combined climate- and prey-mediated range expansion of Humboldt squid (Dosidicus gigas), a large marine predator in the California Current System

“…Since their arrival in Monterey Bay, California in 1997, Humboldt squid have been routinely observed in surveys by remotely operated vehicles (ROVs) in most years since 2002 (Zeidberg & Robison, ; Stewart, ). As highly migratory predators (Stewart et al ., ), Humboldt squid prey on a large number of ecologically and economically important coastal species throughout the northern CCS, including Pacific hake ( Merluccius productus ) and market squid ( Doryteuthis [formerly Loligo ] opalescens ), but their primary prey is mesopelagic micronekton, primarily myctophid fishes (Field et al ., , ).…”

Anticipated Effects of Climate Change on Coastal Upwelling Ecosystems

“…The biological impacts of these events can be catastrophic, with widespread mortality of macroscopic benthic organisms, resulting in periodic dead zones such as those observed on the Oregon continental shelf [61]. Other species, such as Humboldt squid, which have migrated north into the California Current in recent years [63], may be able to take advantage of low-oxygen environments.…”

Chromogenic behaviors of the Humboldt squid (Dosidicus gigas) studied in situ with an animal-borne video package

“…Pop-up archival transmitting (PAT) tags have revealed a great deal about natural vertical movements and swimming behaviors of D. gigas Bazzino et al, 2010;Stewart et al, 2012), but these devices do not reveal the behavioral context for these movements, e.g. foraging, predator evasion or social interactions.…”