報告書番号

484001

タイトル（和文）

溶存酸素量が淡水魚類の生長に与える影響

タイトル（英文）

EFFECTS OF LOW AND HIGH DISSOLVED OXYGEN CONCENTRATIONS ON THE GROWTH OF JUVENILE RAINBOW TROUT, AYU FISH AND CARP

概要 （図表や脚注は「報告書全文」に掲載しております）

ニジマス，アユおよびコイ稚魚が「良好に生長することができる溶存酸素量（ＤＯ）範囲」を実験的に推定した。増重率の値からみて，低ＤＯ，高ＤＯいずれに対する耐性も，検討した３種のうちではコイが最も大きく，次いでアユ，ニジマスの順となると思われた。また，良好な生長を期待できるＤＯ飽和度範囲は，ニジマス：飼育水温１５～１８℃で６０～１４０％，２０～２２度でほぼ飽和域のみ，アユ：飼育水温１７～２０℃で５０～１８０％，２３～２５℃で５０～（１００以上）％，コイ：飼育水温１７～２０℃で５０～２２０％，２３～２５℃で５０～２００％と推定された。ニジマスの場合，水温１５～１８度では摂餌量の減少が，水温２０～２２度では代謝量の増大がＤＯ変化に伴う増重率減少の主因となると推定された。

概要 （英文）

REARING EXPERIMENTS WERE CARRIED OUT TO CLARIFY THE EFFECTS OF DISSOLVED OXYGEN(DO)LEVELS ON THE GROWTH OF JUVENILERAINBOW TROUT,AYU FISH AND CARP.GROWTH RATES OF THESE THREE SPECIES FOR 5 DAYS,AND AMOUNTS OF FOOD CONSUMPTION AND FOOD CONVERSION EFFICIENCIES OF RAINBOW TROUT WERE MEASURED UNDER VARIOUS DO LEVELS SET UP BY NITROGEN OR OXYGEN GAS BABBLING. THE ESTIMATED RANGES OF DO LEVEL IN AIR SATURATION REQUIRED FOR NORMAL AND HEALTHY GROWTH ARE:RAINBOW TROUT;60-140% AT 15-18 DEGREE(C),AYU FISH;50-180% AT 17-20 DEGREE(C),CARP;50-220%AT 17-20 DEGREE(C). DECREASING TENDENCY OF GROWTH RATES OF RAINBOW TROUT SHOWED GOOD COINCIDENCE WITH THAT OF DAILY FEEDING RATES AT THE TEMPERATURE OF 15-18 DEGREE(C)AND WITH THAT OF FOOD CONVERSION EFFICIENCIESAT THE TEMPERATURE OF 20-22 DEGREE(C).DECREASEIN GROWTH RATES OF RAINBOW TROUT SHOULD BE CAUSED MAINLY BY THAT IN AMOUNTS OF FOOD CONSUMPTIONWITH CHANGES IN DO LEVELS AT THE TEMPERATURE OF 15-18 DEGREE(C),WHILE AT THE TEMPERATURE OF 20-22 DEGREE(C)INCREASE OF METABOLIC RATES DUE TOTEMPERATURE INCREASE SHOULD BE THE MAIN CAUSE FOR GROWTH RATE DECREASE.

報告者

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