Title Development of artificial diets and rearing systems for eel larvae - The first success of production of glass eel in captivity -
Authers Hideki TANAKA, Kazuharu NOMURA, Takeshi YAMAMOTO and Hiromi OKU
Keywords Japanese eel, Anguilla japonica, leptocephalus, larval rearing, artificial diet
Citation Bull. Fish. Res. Agen. supplement No. 5, 63-69, 2006
Recently, a slurry-type diet made from shark egg yolk has been identified to be a suitable diet for captive-bred eel larvae. Although preleptocephalus larvae could be reared with this diet beyond the depletion of their yolk and oil droplet stores, it was still incomplete because the larvae could not be raised to glass eel. Then the biochemical compositions of eggs, larvae, and previous diets were analyzed and a new diet was designed by supplement of krill hydrolysate, phytase treated soybean peptide, vitamins, and minerals. A new rearing tank with a device which keeps the inner wall and the bottom of the tank clean by water current set up by water supply was also contrived. Larvae reared with the new diet in the new tank has grew to 50-60 mm in total length and begun to metamorphose into glass eel around 250 days after hatching. We have succeeded for the first time to rear the eel larvae to glass eel. However, the techniques for producing glass eels are not yet firmly established. Further studies should be focused on larval diets and the rearing regimes of the larvae to establish the techniques for consistent mass production of glass eels.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull-b5/15.pdf