Assimilation efficiency of Rhinoceros Auklet ( Cerorhinca monocerata) chicks fed Japanese anchovy ( Engraulis japonicus) and Japanese sand lance ( Ammodytes personatus)

Abstract

We investigated the assimilation efficiency (AE) of a piscivorous alcid, Rhinoceros Auklet ( Cerorhinca monocerata), chicks when fed Japanese anchovy ( Engraulis japonicus) and Japanese sand lance ( Ammodytes personatus), which are their main prey species. The assimilation efficiency corrected for nitrogen retention (NR) of the chicks fed sand lance (81.6%) was significantly higher than those fed anchovy (78.0%). The values of assimilation efficiencies for both fish species are similar to those of fish-fed seabird adults and fledglings.