| As one of the important fisheries resource in China, Portunus trituberculatus and Fenneropenaeus chinensis are target species in aquaculture and fishing. Their resources have been depleted as the influence of overfishing and environmental deterioration. Stock enhancement is widely employed in P. trituberculatus and F. chinensis recently as a supplement to natural resource. However, a kind of marking method about the evaluation of effect has been lacked for the feature that massive quantity and small size. The mtDNA control region and microsatellite markers as marking method are used for discuss the effect of the stock enhancement, as the aim of providing scientific reference and technical support for future work. (A) The effect of stock enhancement about P. trituberculatus baesd mtDNA and microsatellite markers(1) mtDNA.524 broodstock and 547 recaptured crabs were analyzed by mtDNA control region. Results of mtDNA control region showed that:234 broodstock sharing no haplotype with recaptured crab were excluded among a total of 524 broodstock. In the 547 recaptured crabs,242 individuals sharing no haplotype with the broodstock were excluded for not being the juvenile released, accounting for 44.24%. The remaining 305 recaptured crabs, accounting for 55.76%, were needed further experiment to confirm the origin by microsatellite. (2) The microsatellite markers were used for analyze the alleles between the rest 290 broodstock and 305 the recaptured carb sharing the same haplotype. The results showed that 200individuals are excluded in the broodstock, that corresponding no recaptured carb.223 individuals were not the released juvenile among the recaptured crabs, accounting for 40.77%. The remaining 81 recaptured crabs were released juvenile, accounting for 14.81%.In summary,434 out of 524 broodstock made no contribution to the recaptured crabs while 90 individuals were consistent with the release-recaptured shrimp.81 recaptured crabs were released juvenile in spring, accounting for 14.81% of the total. Additionally, the origins of the re lease-recaptured crabs were clear by using the molecular markers, so the respective effects can be evaluated. The results showed that mtDNA control region and microsatellite markers were effective in evaluation of stock enhancement.(B) The effect of stock enhancement about F. chinensis baesd microsatellite markersBased on the preliminary experiment, that broodstock and recaptured shrimp were analyzed by mtDNA control region, three haplotypes were chosen for further experiment by microsatellite markers, to evaluate the effect of stock enhancement and genetic difference between generations.One hundred and twenty-three broodstock and one hundred senventy-four recaptured shrimp were analyzed by eight microsatellite loci. (1) 90 recaptured shrimp were consistent with the broodstock by using the eight microsatellite loci, proving they were released juvenile in spring, and accounting for 51.72% of the total. (2) Different season had different effects. In the autumn,79 out of 140 recaptured shrimp were released juvenile; higher than the next spring those 11 out of 34 individuals. (3) Specification had effect on stock enhancement. Among 90 release-recaptured shrimp, 43 individuals were large size and 47 were small size. The effect of small size juvenile was no less than the large one. (4) Broodstock made different contributions to released shrimp, especially a small part of broodstock bred most releasing juvenile.Thrity-nine broodstock and eighty-five recaptured shrimp were analyzed by eight microsatellite loci. (1) Among the 85 recaptured shrimp,20 individuals were consistent with the broodstock on the eight microsatellite loci, proving they are the released juvenile, accounting for 23.53% of the total. (2) The origin of the re lease-recaptured shrimp can be infer that Changyi sea-recaptured broodstock were corresponded with 10 individuals, Changyi over-wintering broodstock were corresponding with 8 individuals and Wudi broodstock were corresponding the rest two. (3) Among the release-recaptured shrimp, six individuals were the second generation of the brood stock in 2012.Genetic diversity index were calculated in the experiment and the results showed that:(1) High genetic diversity was observed in Chinese shrimp populations. (2) Inbreeding was serious in every population. (3) There was no significant genetic differentiation among four populations of three generations.In summary, the effect of stock enhancement of Chinese shrimp was significant because there is certain proportion released juvenile in the recaptured shrimp in autumn. What’s more, the released juvenile were detected in the recapture in next spring, proving that the supplement was persistent program. However the inbreeding was serious in every population and took a big risk on genetic diversity. |
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