State of Satiation Partially Regulates the Dynamics of Vertical Migration

Vertical migrations into shallower waters at night are beneficial for migrators as they reduce predation risk and allow to encounter a higher density of prey. Nevertheless, ocean acoustics data trawl have shown that portion some vertically migrating populations remain depth do not migrate. One hypothesis this phenomenon is the Hunger-Satiation hypothesis, which in part states non-migrating species-assemblage refrains from if full or partially stomachs daytime nocturnal feeding. However, stomach fullness subpopulation compared has rarely been studied, due difficulty obtaining sufficient samples. The levels numerically abundant crustacean fish species with well-known distributions were quantified present study. Animals captured during trawls discrete-depth intervals between 0 1,500 m. Stomach indices assigned 5 migratory taxa caught shallow deep waters. Data crustaceans Acanthephyra purpurea, Gardinerosergia splendens, Plesionika richardi , Systellaspsis debilis well fishes Lampanyctus alatus, Lepidophanes guentheri Notolychnus valdiviae provided support while Gennadas capensis valens Benthosema suborbitale did not. These findings suggest vacancy may be just one several factors regulating dynamics vertical migration those whose behavioral plasticity suggests daily “choices” whether