ヒラメの混合栄養期仔魚の発育

• 茂木 正人

  福山大学

• 石川 健

  福山大学

• 伏見 浩

  福山大学

書誌事項

タイトル別名

• Development of Mixed-feeding Stage Larvae of Japanese Flounder, Paralichthys olivaceus (Pisces: Paralichthyidae)

抄録

ヒラメ仔魚の成長,卵黄と油球の吸収様式,形態発育および初期摂餌量の変化を,鮮化直後から158時間(158HAH)調べた。その結果,栄養転換過程は以下のように分けられた:1)内部栄養期:艀化〜90HAH(全長2.2〜3.6mm),2)混合摂餌期:90〜140HAH(3.6〜4.2mm),3)外部栄養期:140HAH〜(4.2mm〜)。また,50〜60HAH(3.4〜3.5mm)には内部栄養の吸収速度に変曲点が認められ,何らかの生理的な変化が起こることが示唆された。この時期は開口の時期とほぼ一致することから,内部栄養期をさらに前開口期と後開口期に分けた。ヒラメ仔魚の栄養転換過程を,これまでに知られているその他の海産魚種と比較したところ,ヒラメでは摂餌開始時の内部栄養量が少なく,これは初期仔魚の生残には不利な形質と考えられた。一方で,内部栄養の吸収完了時に摂餌量が多いこと,摂餌開始から100%摂餌までの時間が短いこと,および摂餌開始時の全長が大きいことなど,初期摂餌に関しては,円滑な栄養転換をサポートする特徴をもつことも明らかとなった。
Early growth, yolk and oil exhaustion, early morphological development and initial feeding were examined in laboratory-reared larvae of the Japanese flounder, Paralichthys olivaceus. Based on nutritional transition, the early larval stage of Japanese flounder was divided as follows: the endogenous nutritional phase from hatching (mean total length 2.2 mm) to 90 hours after hatching (HAH) (3.6 mm); a mixed-feeding phase from 90 to 140 HAH (4.2 mm); and an exogenous feeding phase after 140 HAH. Furthermore, the endogenous nutritional phase was divided into two sub-phases at around 50-60 HAH (3.4-3.5 mm), at which time flexion points were apparent on the semi-logarithmic plots of yolk and oil globule absorption. This border coincided with the first observations of mouth opening. In the pre-mouth-opening phase from hatching to 50-60 HAH, a rapid increase in larval growth rate was recorded, while growth rate was slower in the post-mouth-opening phase. Based on comparisons with early-life-stage features of other marine fish species, Japanese flounder larvae retained very few endogenous nutritional resources at the onset of feeding, a characteristic that is disadvantageous for survival in spite of a long mixed feeding period. However, the high rate of feeding at the exhaustion of endogenous nutrition, the reduced time from initial feeding to 100% feeding, and the large larval size at the onset of feeding found in this study are considered to advantageous features supporting the nutritional requirements of larvae.

収録刊行物

• 福山大学内海生物資源研究所報告

  福山大学内海生物資源研究所報告 12 1-10, 2001-12

  福山大学

キーワード

• flounder
• Paralichthys olivaceus
• nutritional resources
• larval development
• oil globule
• yolk
• mixed feeding period

詳細情報

• CRID: 1570572702578168576
• NII論文ID: 110007405962
• NII書誌ID: AA1157543X
• ISSN: 09178147
• 本文言語コード: en
• データソース種別:
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