タマガンゾウビラメ・メイタガレイ仔魚の鉛直分布と食性〔若狭湾に出現する仔魚の食性に関する研究-3-〕

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This paper deals with vertical distribution and feeding habits of two larval flatfish Pseudorhombus pentophthalmus GÜNTHER and P! euronichthys cornutus (TEMMINCK et SCHLEGEL), collected in the western wakasa Bay, Japan Sea from May to August 1981. The larvae of two species distributed abundantly in the waters between 25m and 50m depths. The larvae of P. pentophthalmus of 3.0-3.9mm body length began to feed on invertebrate eggs (6.2%, showing the percentage of number of food items) and Chaetoceros spp. (75.0%), the larvae of 4.0-4.9mm fed mainly on copepod nauplii (92.3%), and the larvae of more than 5.0mm fed abundantly on Paracalanus parvus (11.1-17.9%), Penilia avirostris (5.6-40.0%) and Oikopleura longicauda (10.3-83.3%). Most of P. cornutus larvae of 4.5-8.2mm body length ate particularly O. longicauda. From digestive degree of O. longicauda in each larva gut, it is suggested that the larvae feed on the large amount of O. longicauda for a short time nd that the diurnal aggregated distribution of O. longicauda is closely related to the feeding habite of P. cornutus. According to the feeding habits of three flatfish collected together in the western Wakasa Bay, the availability of O. longicauda as food is in the order of P. cornutus, P. pentophthalmus and Paralichthys olivaceus.