Data from: Impact of squid predation on juvenile fish survival

Predation is a major source of mortality during the early life stages of
marine fishes; however, few studies have demonstrated its
impact—especially that of squid predation—on survival processes. Here, we
examined the feeding habits and predation impacts of swordtip squid on a
major prey fish, juveniles of jack mackerel, in the East China Sea.
Otoliths of the juveniles extracted from the squid stomach were used to
reconstruct the age–length relationship and the growth trajectory of the
consumed juveniles, and they were compared to those of juveniles collected
with a net using a newly developed statistical framework. The juveniles
consumed by squid had significantly shorter body lengths and smaller body
sizes during the late larval and early juvenile stages than the netted
juveniles, suggesting that smaller juveniles with slower growth rates have
a higher probability to be selected. The body mass ratio of the predator
squid to prey juveniles (predator-prey mass ratio, PPMR) ranged from 7 to
700, which was remarkably lower than the PPMR reported in various marine
ecosystems based on analyses of fishes. Our findings demonstrate that
squid predation can significantly impact the early life survival of fish
and the trophodynamics in marine ecosystems.