Feeding habits of the glass shrimp Pasiphaea japonica in Toyama Bay of the Sea of Japan

Abstract

Feeding habits of the glass shrimps Pasiphaea japonica found in Toyama Bay of the Sea of Japan were studied. Once a month between April and November 2004, specimens were collected by commercial boat seining in the fishing grounds of P. japonica in Toyama Bay. In the laboratory, 50 shrimps were selected randomly, and the foreguts were eviscerated under a stereoscopic microscope. The results showed that P. japonica fed on mysids, euphausiids, other crustaceans (copepods, amphipods, P. japonica, unidentified crustaceans), fishes, and cephalopods. Among these, mysids and euphausiids made up the main diet of P. japonica. It is expected that P. japonica feeds on mysids near the sea bottom, because mesopelagic mysids were not dominant in the fishing grounds. As P. japonica grew, mysids became the main prey. Euphausiids are prey on which P. japonica feeds during the summer, especially in August and September. Euphausiids were consumed regardless of body size of P. japonica.