GENETIC DIVERSITY AT EACH HABITAT OF PSEUDOLABRUS SIEBOLDI, USUAL FISH SPECIES IN A WESTERN JAPAN COASTAL AREA

Abstract

Pseudolabrus sieboldi is a very common labrid fish in Japan coastal region, so the species wasn't
being watched so much up to now. Therefore, the habitats of P. sieboldi have been developed easily. But it's
pointed out that genetic isolation easily occurred due to being polygyny in their mating system. In order to
investigate the genetic diversity of usual species, we sampled 6 populations of the species form western Japan
coastal area, and studied them for allelic variation at 24 enzyme loci. In comparison with other sea fishes, the
total genetic diversity is standard. Though sex ratio was inclined to females and inbreeding were easy to be
performed, the gene diversity was not decreasing. In fact, there was inbreeding mating within the population.
Moreover, standard genetic distance within populations along the Japan Sea is high and standard genetic
distance within Pacific Ocean area is low. The fry of the species dispersed to the Pacific or the Japan Sea.
When they grew adults, they returned to rocky shores for mating. The populations along the Pacific Ocean did
not return exactly at their birth area. On the other hand, the populations along the Japan Sea returned more
exactly at their birth area.