A bstract Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole,Cynoglossus semilaevis,were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As ph...A bstract Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole,Cynoglossus semilaevis,were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As phenotypic males with female genotypes,neo-males are harmful in C. semilaevis aquaculture because they reduce overall production. The present study evaluated the difference in the growth-related traits: total length(TL),body weight(BW) and square root of body weight(SQ_BW) at the age of 570 days between normal and neo-male offspring(neo-males used as male parents). The difference in the proportion offemales between normal and neo-male offspring was also assessed. Based on the linear mixed model,restricted maximum likelihood(REML) and best linear unbiased prediction(BLUP) were used to estimate various(co)variance components and estimated breeding values(EBVs) of growth-related traits. As a result,all the mean values of the three studied traits were significantly larger in normal offspring than in neo-male offspring. Additionally,the female proportion was significantly larger in normal offspring than in neo-male offspring. Heritability was 0.128±0.066 2 for TL,0.128±0.065 5 for BW and 0.132±0.062 9 for SQ_BW,all of which were low level heritabilities. The correlation coefficients of EBVs and phenotypic values of the target traits were 0.516 for TL,0.524 for BW and 0.506 for SQ_BW,all of which were highly significant( P <0.01). Genetic correlations among TL,BW and SQ_BW were positive high(0.921–0.969) and higher than those of phenotype(0.711–0.748),both of which had low standard errors(0.063–0.123 for genotype,and 0.010–0.018 for phenotype). Compared with normal offspring,neo-male offspring have lower breeding values for each studied trait through EBVs comparison. Therefore,neo-male offspring should not be used as broodstock in a C. semilaevis breeding programs.展开更多
Two methods, tagging and ink injection, are used in the grouper releasing experiment. The studied fishes are the juvenile of Epinephelus akaara and Epinephelus awoara both artificially cultivated and caught from natur...Two methods, tagging and ink injection, are used in the grouper releasing experiment. The studied fishes are the juvenile of Epinephelus akaara and Epinephelus awoara both artificially cultivated and caught from natural waters, and their wild adults. Experimental results show that the inhabiting behaviours for both juvenile and adult fishes show distinct regionality, which move within an area of 2 n mile diameter 651 days and 48 days after being released, respectively. With the tagging method, the tagged fishes could only be recaptured in the year of release while, with the injection method, they could be caught in the lst, 2nd and 3rd years. It is confirmed that in the cement tank, the tagged fishes lose their 1/3 tags. That means that the tagging method is not fit for the release research while the injection method is. Generally, the recaptured rates of injected fishes are 1.4 ～ 4.5 %, 3.1 ～ 13.4 % and 2.7 % for the 1st, 2nd and 3rd years, respectively.展开更多
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A403-2)the Taishan Scholar Project of Shandong Province of China
文摘A bstract Phenotypic and genetic parameters for growth-related traits in the half-smooth tongue sole,Cynoglossus semilaevis,were estimated in 22 full-sib families produced by normal and neo-male breeding stocks. As phenotypic males with female genotypes,neo-males are harmful in C. semilaevis aquaculture because they reduce overall production. The present study evaluated the difference in the growth-related traits: total length(TL),body weight(BW) and square root of body weight(SQ_BW) at the age of 570 days between normal and neo-male offspring(neo-males used as male parents). The difference in the proportion offemales between normal and neo-male offspring was also assessed. Based on the linear mixed model,restricted maximum likelihood(REML) and best linear unbiased prediction(BLUP) were used to estimate various(co)variance components and estimated breeding values(EBVs) of growth-related traits. As a result,all the mean values of the three studied traits were significantly larger in normal offspring than in neo-male offspring. Additionally,the female proportion was significantly larger in normal offspring than in neo-male offspring. Heritability was 0.128±0.066 2 for TL,0.128±0.065 5 for BW and 0.132±0.062 9 for SQ_BW,all of which were low level heritabilities. The correlation coefficients of EBVs and phenotypic values of the target traits were 0.516 for TL,0.524 for BW and 0.506 for SQ_BW,all of which were highly significant( P <0.01). Genetic correlations among TL,BW and SQ_BW were positive high(0.921–0.969) and higher than those of phenotype(0.711–0.748),both of which had low standard errors(0.063–0.123 for genotype,and 0.010–0.018 for phenotype). Compared with normal offspring,neo-male offspring have lower breeding values for each studied trait through EBVs comparison. Therefore,neo-male offspring should not be used as broodstock in a C. semilaevis breeding programs.
文摘Two methods, tagging and ink injection, are used in the grouper releasing experiment. The studied fishes are the juvenile of Epinephelus akaara and Epinephelus awoara both artificially cultivated and caught from natural waters, and their wild adults. Experimental results show that the inhabiting behaviours for both juvenile and adult fishes show distinct regionality, which move within an area of 2 n mile diameter 651 days and 48 days after being released, respectively. With the tagging method, the tagged fishes could only be recaptured in the year of release while, with the injection method, they could be caught in the lst, 2nd and 3rd years. It is confirmed that in the cement tank, the tagged fishes lose their 1/3 tags. That means that the tagging method is not fit for the release research while the injection method is. Generally, the recaptured rates of injected fishes are 1.4 ～ 4.5 %, 3.1 ～ 13.4 % and 2.7 % for the 1st, 2nd and 3rd years, respectively.
