Influence
of hatchery protocols on mitochondrial DNA variation in Japanese flounder
juveniles
T.
Asahida, Y. Shinotsuka, Y. Yamashita, K. Saitoh, K. Hayashizaki, H. Ida-2003
Journal
of the World Aquaculture Society, 34(2): 121-132
(from ISI Current Contents)
Abstract:
The Japanese flounder Paralichthys olivaceus is a commercially important
fish that is stocked extensively from hatchery rearing programs in Japan. To
examine the genetic variability of hatchery-raised juveniles of the Japanese
flounder that are used for stocking into natural waters, we analyzed a
portion of the mitochondrial genome. The mtDNA region extending from the 3'
half of the cytochrome b gene to the central domain of the control region
was PCR amplified and analyzed using 11 restriction endonucleases. We
identified 34 polymorphic cleavage sites out of a total of 61 sites, which
resulted in 67 different haplotypes in a total of 265 offspring, examined
from eight hatchery stocks. Haplotype diversity of offspring at each of the
eight hatcheries ranged from 0.49 +/- 0.09 (SE) to 0.94 +/- 0.03 (SE). Also,
we observed 40 polymorphic sites out of a total of 59 sites, which resulted
in a total of 50 haplotypes in 60 wild flounder. Haplotype diversity of the
wild population was 0.98 +/- 0.01 (SE). The use of subcultured fishes as
broodstock appears to be one of the most important causes of reduced genetic
diversity in hatchery-raised flounder juvenile. Our results suggest that the
use of wild fish for broodstock is an effective way to maintain genetic
variability in Japanese flounder offspring.
(Kitasato University, School of Fisheries Sci.,
Sanriku Iwate 0220101, Japan)