報告書番号

U89003

タイトル（和文）

海産稚仔魚飼育の好適光条件

タイトル（英文）

STUDIES ON THE OPTIMAM LIGHT CONDITIONS OF REARING OF MARINE FISH LARVA AND JAVENILES

概要 （図表や脚注は「報告書全文」に掲載しております）

海産稚仔魚の成長促進や初期生残の向上を図る上で好適な光条件を求めることを目的として，明るさ，光周期などが稚仔魚の摂餌活動，生残，成長に与える影響について，クロダイ，マダイ，シロギスなどを用いて実験的に検討した。その結果，３０リットル容パンライト水槽を用いた場合，仔魚の成育に好適な水面照度はクロダイ：３０００ｌｕｘ，マダイ：１８０～２８００ｌｕｘ，シロギス：検討した０～１０の４条ｌｕｘの範囲で２８００ｌｕｘ以上であることがわかった。また，クロダイ仔魚，シロギス仔魚では，人工照明を行えば夜間も摂餌活動が行われ，成長促進を図り得ることがわかった。

概要 （英文）

THOUGH CONSIDERABLE EFFORTS HAVE BEEN MADE TO CONTROL REARING CONDITIONS,WE HAVE LITTLE INFORMATION AVAILABLE OF LIGHT CONDITIONS. THIS PAPER REPORTS ON LABORATORY REARING EXPERIMENTS UNDERTAKEN TO DETERMINE THE EFFECTS OF LIGHT CONDITIONS ON THE EARLY SURVIVAL,GROWTH AND FEEDING OF ACANTHOPAGRUS SCHLEGELI,PAGRUS MAJOR AND SILLAGO JAPONICA. LARVAE AND/OR JUVENILES OF EACH SPECIES WERE REARED IN 30LITRE-VOL. FRP REARING TANKS IN EXPERIMENTAL ROOMS OF ABIKO RESEARCH CENTER,CRIEPI IN CHIBA PREF.,JAPAN. TEST INDIVIDUALS WERE SUBJECTED TO SELECTED CONTINUOUS AND CONSTANT LIGHT INTENSITIES BETWEEN 0 AND 10000 LUX AT WATER SURFACE, OR UNDER FOUR PHOTOPERIODS AT 2800 3000 LUX : 24H LIGHT-OH DARK(24L),18L,13L(NEARLY NATURAL DAYLENGHT) AND 8H. RESULTS ARE AS FOLLOWS: 1.LIGHT INTENSITY (1)ANY POSTLARVAE OF EACH SPECIES COULDNOT SURVIVE AT 0 LUX AFTER YOLKSAC ABSORPTION. (2)THE BEST GROWTH AND SURVIVAL OF POSTLARVAE WERE OBTAINED AT 3000 LUX ON A. SCHLEGELI,AT 1802800 LUX ON P. MAJOR,AND 2800 LUX OR MORE ON S. JAPONICA. 2. PHOTOPERIOD (1)LONGER PHOTOPERIODS SIGNIFICANTLY INCRESED GROWTH OF A. SCHLEGELI,POSTLARVE, AND SURVIVAL AND GROWTH OF S. JAPONICA POSTLARVAE. (2)POSTLARVAE OF THESE TWO SPECIES COULD NOT SURVIVE UNDER 8L PHOTOPERIOD. (3)NO DIFFERENCE IN POSTLARVA SURVIVAL AND GROWTH OF P. MAJOR WAS OBSERVED AMONG 24L,18L AND 13L PHOTOPERIODS. (4)POSTLARVAE OF P. MAJOR COULD SURVIVE AND GROW UNDER 8L PHOTOPERIOD. THEIR SURVIVAL AND GROWTH RATE UNDER 8L,HOWEVER,WERE SIGNIFICANTLY LOWER THAN THOSE UNDER 24L,18L,OR 13L PHOTOPERIOD. (5)LONGER PHOTOPERIODS COULD NOT PROMOTE JUVENILE SURVIVAL AND GROWTH OF A. SCHLEGELI AND S. JAPONICA.

報告者

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