報告書番号

U93056

タイトル（和文）

高能率魚類生産のための水質浄化技術の開発 １１．養魚システムの物質収支と物理化学的浄化法の評価

タイトル（英文）

Development of Water Purification Technologies for Intensive Fish Culture 11.Material balance in the fish culture system and evaluation of physical chemical treatment

概要 （図表や脚注は「報告書全文」に掲載しております）

循環濾過養魚システムにおける物質収支を明らかにするとともに、物理化学的給化法によるヒラメ飼育水の浄化能力を評価した。物理化学的浄化装置として、底掃除機、紫外線照射装置、オゾン発生装置、プロテインスキマーを、総水量３ｍ３の循環濾過システムに組み込み、ヒラメを２ヶ月間飼育した。配合飼料として養魚システムに入った炭素・窒素のうち、３０％Ｃ、４０％Ｎがヒラメの成長に用いられ、１％Ｃ、２％Ｎが溶存有機物となり、５％Ｃ、４％Ｎが汚泥となった。また、残りの６４％Ｃは二酸化炭素などとなりシステム外に出たと考えられ、５４％Ｎは硝酸として飼育水に蓄積した。物理化学的浄化により、飼育水に蓄積する溶存・懸濁有機物濃度が減少し、ヒラメの増重率と飼料効率が向上した。有機物の分解に関しては、紫外線照射の寄与が最も大きかった。

概要 （英文）

A material balance in a closed recirculating fish culture system for Japanese flounder was investigated.The physical-chemical methods of organic matter removal were also evaluated in the system.Closed fish culture systems of 3m3 water volume had been operated for two months.settled sludge cleaner,ultraviolet sterilizer,ozone generator,and protein skimmers were used for physical-chemical treatments.Each of the elements C and N constituting the pelleted food introduced into the fish culture system was transferred into the components of fish body(30%C and 40%N),of dissolved organic matter in the culture water(1%C and 2%N),and of sludge(5%C and 4%N).Nitrate accumulated in the culture water accounted for 54% of N added as the component of the food.The restof carbon(64%)may be transferred into inorganic carbon by fish respiration and biodegradation,and escaped into the air.Accumulations of dissolved and particulate organic matter in the rearing water were decreased significantly due to the physical-chemical treatments.The weight gain of Japanese flounder and feed conversion efficiency were consequently increased.In the physical-chemical treatments investigated,ultraviolet irradiation is effective for removal of dissolved organic matter in the system.

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