Mitochondrial DNA markers confirm successful stocking of mud crab (Scylla paramamosain) juveniles into a natural population
2002
Imai, H. (Tokai Univ., Shimizu, Shizuoka (Japan). Coll. of Marine Science and Technology) | Obata, Y. | Sekiya, S. | Shimizu, T. | Numachi, K.
The effectiveness of stocking artificially propagated mud crab, Scylla paramamosain juveniles was measured by releasing the juveniles tagged by variation of mitochondrial DNA (mtDNA) D-loop region. One hundred and forty nine females werecollected to use for artificial propagation, at Urado Bay Kochi Prefecture, Japan. The fourth leg of each was removed by autot-omy, then one haplotype, #2 was selected for propagation. Only one female of 23 females showing this haplotype spawned about 3.35 million larvae. Thereafter, about 100,000 juveniles grown up to 9.6mm in average carapace width were released at 25 fishing grounds in Urado Bay during May 1997. A total of 653 crabs were then collected at these sites by seven times of sampling made between Aug. 1997 and Dec. 1998. The frequency of haplotype #2 used as a genetic tag increased significantly after stocking from 15.4% to 29.6%. Thus, the ratio of released juveniles to all the mud crabs in Urado Bay was estimated to be 16.8%. The composition of the haplotype in the samples collected at the end of 1998 suggested that the fecundity of stocked crabs are the very same with those of natural stock. The relevance of mtDNA markers for stocking project and the problem of genetic management of aquatic organisms are discussed.
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