It is well established that squid play an important role in marine ecosystems. Squid not only serve as an important source of food for top predators, but are considered important predators themselves. Although squid are nearly exclusively carnivorous hunters, ontogenetic diet change has been described in many species. The Patagonian long-fin squid Doryteuthis gahi (d'Orbigny, 1835) has an annual life cycle with two annual hatching events. These squid are schooling on continental shelves, transporting energy from lower trophic levels to top predators. Earlier studies at the Patagonian shelf investigating the stomach contents of D. gahi found a predominance of small euphausiids, but no study so far studied differences between spawning cohorts or decadal diet shifts. The present study investigated differences in diet of D. gahi at the Patagonian shelf between two different sampling periods in terms of temporal diet shift and differences between spawning cohorts. General additive models were used to model the influence of mantle length, sampling period and spawning cohort on the diet. Results revealed an ontogenetic diet change from euphasids in small squid to fish and cephalopods at bigger sizes as well as an opportunistic feeding behaviour of D. gahi. Furthermore, the use of a new food source, Munida gregaria was observed, related probably to an increased abundance of this Lobster Krill. Findings of this study will be used for future ecosystem modelling, leading to an improved management of the Falkland Islands marine environment

Cephalopod International Advisory Council Conference, Cephalopods in the Anthropocene: Multiple Challenges in a Changing Ocean, April 2-8, 2022, Sesimbra, Portugal

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