Feeding ecology of two lanternfishes Diaphus garmani and Diaphus chrysorhynchus

摘要

The feeding ecology of two dominant lanternfishes Diaphus garmani and Diaphus chrysorhynchus was studied in the continental slope region of the East China Sea, off western Kyushu (3133 degrees N; 128130 degrees E). Stomach contents of D. garmani were composed mainly of crustacean zooplankton, such as copepods, euphausiids, decapod larvae and amphipods, and also of appendicularians. Stomach contents of D. chrysorhynchus were composed mainly of crustacean zooplankton, cephalopods and fishes. Diel changes in stomach fullness indicated that D. garmani fed more actively at night than in the day. On the other hand, although feeding activity of D. chrysorhynchus did not change drastically between day and night, it tended to feed on large prey items in the benthopelagic zone during the day and on zooplankton in the epipelagic zone at night. Daily rations of food were estimated to be 2 center dot 54% of body dry mass for D. garmani, and 2 center dot 38% of body dry mass for D.chrysorhynchus.