Title Estimation of the heritability for growth rate in the Nikko strain rainbow trout( Oncorhynchus mykiss) using the individual identifying method with passive integrated transponder(PIT)tags.
Authers Ryozo Sato, Teruo Azuma and Koji Muto
Keywords Rainbow trout, Growth rate, Heritability, PIT tag, Individual identfication
Citation Bull. Fish. Res. Agen. No.16, 1-7, 2006
The genetic variations in growth rate of Nikko strain rainbow trout were analyzed. Eight males were mated with 20 females using a hierarchical design. Fish from the 20 crosses were raised separately to an average standard length of 11.5~13.0cm and average body weight of 25.9~37.3g. Five hundred and ninety-three fish were then individually PIT tagged and reared in a pond for the growth experiment through 90 days. In this study, one fish died, and 22 fish were not able to be identified. These 22 fish included fish that had lost the tag and also fish that had ingested lost tags. However, information concerned with the growth rate was obtained from 570 fish. Mean values for the ratio of the final to initial body length and body weight were 1.215 and 1.686, respectively. From analysis of variance of half-sib, heritabilities based on the sire components for the ratio of the final to initial body length and body weight were estimated to be 0.242 and 0.261, respectively. These values indicate that individual selection may be effective to improve growth of Nikko strain rainbow trout to some degree.
The method of individual identification by PIT tag is considered to be effective for such genetic studies based on a hierarchical design, because all the examination fish can be reared on one pond after installing the tag and the individual number can be identified from the outside by the detecter without damaging fish.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull16/satou.pdf