Molecular analysis of genetic variation and relationships amongst abalone (Haliotis midae) at the I&J abalone hatchery at Danger Point, Gansbaai, R.S.A.

[摘要] ENGLISH ABSTRACT: The species Haliotis midae is the only abalone species of commercial importance to theSouth African fisheries industry. The species is currently under substantial pressure dueto commercial harvest and illegal poaching, to the extent that genetic and biodiversitymay be under threat. The species is also being cultured in commercial systems forsupply to international markets. The South African production for 2002 amounted to350 tons. The commercial production of abalone may also have implications withregard to genetic diversity of natural and commercial populations.The aim of this project was to assess the genetic diversity of the natural and commercialpopulations of abalone at the I&J Abalone Farm, Danger Point, Gansbaai, in SouthAfrica, in order to make recommendation with regard to possible impact on naturaldiversity as well as internal management systems. Distortion of natural genetic diversityor a loss of internal diversity will have detrimental consequences.Representative samples have been obtained from the surrounding natural population, aswell as the commercial populations, including the broodstock and various progenygroups. Both mtDNA and AFLP molecular techniques were used to assess geneticdiversity.Data analysis showed that the genetic profile of the commercial population displaysufficient genetic variation. The genetic structure of the commercial population alsodisplays no significant deviation from that of the surrounding natural population, i.e. thepopulation of origin. The results through give indication of a small, thoughunsignificant loss of genetic variation from the broodstock to the subsequent progenygroups.The investigation conclude that the commercial populations of abalone at the I&JAbalone Farm, Danger Point, Gansbaai, in its current format holds no threat to thedisruption of the genetic diversity of the surrounding natural population. Further, thecommercial population possesses sufficient genetic variation in view of future geneticdevelopment. There is signs of a slight loss of genetic variation in the change over fromthe broodstock to the progeny groups. This would necessitate careful and controlledreplacement of the original broodstock with new animals from the commercial progenygroups as part of an ongoing process of domestication.

[发布机构] Stellenbosch University