噴火湾におけるアカガレイおよびイシガレイ仔魚の食性 : 尾虫類 Oikopleura の餌生物としての重要性

概要

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To evaluate the importance of Oikopleura as prey for flatfish larvae, we investigated species composition of appendicularians in the diets of flathead flounder Hippoglossoides dubius and stone flounder Platichthys bicoloratus larvae in Funka Bay in winter and spring (January-May) from 2006 to 2010. 0ikopleura dioica and 0. longicauda were abundant in the bay in January, and 0. labradoriensis increased its population density in February and March. Preflexion, flexion, and small postflexion larvae of flathead flounder fed mainly on invertebrate eggs and copepod nauplii, and large postflexion larvae fed on Oikopleura. Stone flounder larvae fed mainly on Oikopleura through their larval stages, especially in the large larvae. Based oncomparison of the inlet filter-like structure in house rudiments of Oikopleura in the flatfish guts, we could identify to species level with a house-rudiment length greater than 550μm. The flatfish larvae fed heavily on 0. labradoriensis. This species can feed on smaller organisms, has a longer life span than other Oikopleura and may have an important role as a trophic shunt from primary producers to the larvae.
2011-08-26