Developmental Biology In The Early Life Stages And Genetic Diversity Of The Tonguefish (Cynoglossus Semilaevis)

The tonguefish (Cynoglossus semilaevis) have been regarded as a valuable rare species indigenous to the Bohai Sea and the Yellow Sea and a perfect target species for seafarming and sea ranching. Presently, the tonguefish resources have been depleted to be in severe danger partly due to overfishing and its special particularities of reproduction (significant differences of abundance and body sizes between the females and males). Witnessing the pilot success in artificially seedling rearing, the project observed those fishery biological and ecological characteristics in the early life stages of the tonguefish like morphological, ecological and reproductive features and detected the genetic diversities in the animal by using those techniques like chromosomal karyotyping and band-patterning, analysis of biochemical composition in muscle tissues, isozyme electrophoresis and those DNA variations like RAPD, AFLP, mitochondrial DNA Cyt b and 16S rRNA gene sequencing. Moreover, the molecular phytogeny relationship among 14 species in the Sub-family Cynoglossinae was analyzed as revealed by mitochondrial Cyt b and 16S rRNA gene sequencing. As a result, some measures for the responsible utilization and protection of the genetic resources of this valuable animal were put forth. The results of the project will lay a theoretic foundation not only for the protection of the rare resources but also for the Seedling Project of Seafarming and Sea Ranching.Over more than three-years-implementation, the following five aspects of achievements were obtained:1. The morphological and ontogenic characters at the early stages covering the period from the fertilized eggs to 2-months-old juvenile tonguefish Cynoglossus semilaevis were observed and described. The occurrence and vanish of some organs such as crownlike larval fin, pectoral fin and swimming bladder were described.The ontogenic features at early life stages of Genus Cynoglossus species were compared. Besides, the...