In this work we used upper and lower beaks of Moroteuthopsis longimana collected from the diet of Antarctic toothfish Dissostichus mawsoni from the Pacific (Ross and Amundsen Seas) and Atlantic (South Sandwich Islands) sectors of the Southern Ocean to study the feasibility of using beaks collected from predators’ stomachs to study the age of Southern Ocean oceanic squid and to estimate the age and growth patterns of M. longimana. We analysed the presence of micro-increments in the rostrum sagittal section (RSS) and the lateral wall of both upper and lower beaks. Lower beak’s RSS was the only section where it is possible to observe and count a readable sequence of increments that allowed to estimate the age of oceanic squid using beaks collected from predators’ stomachs. This dataset contains the number and width of increments found in the RSS of the 10 M. longimana’s lower beaks used in this study. Further information related with the studied beaks such as beak measurements, origin and sample date can be found in the published article. This dataset is associated with the article: Queirós JP, Bartolomé A, Piatkowski U, Xavier JC, Perales-Raya C (2023) Age and growth estimation of Southern Ocean squid Moroteuthopsis longimana: can we use beaks collected from predators’ stomachs? Marine Biology 170, 10. DOI 10.1007/s00227-022-04156-2

This work was supported by the strategic program of Marine and Environmental Sciences Centre (MARE), financed by the FCT (UIDB/704292/2020). JPQ was supported by a FCT/MCTES through national funds (PIDDAC) and Portuguese Polar Program (PROPOLAR) and by FCT PhD scholarship co-financed by FSE (SFRH/BD/144320/2019).