1National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hatsukaichi, Hiroshima 739-0452, 2Kagoshima Prefectural Fisheries Technology and Development Center, Ibusuki, Kagoshima 891-0315, 3Field Science Center for Northern Biosphere, Hokkaido University, Akkeshi, Hokkaido 088-1113, Japan
The Zostera marina bed is an important habitat for the biological productivity and diversity of coastal marine organisms including various important fishery species. Seed dispersal is a definitive factor to that regulates the annual Z. marina production and is inportant for maintaining the annual Z. marina beds. This study examined the seed dispersal dynamics of the annual Z. marina based on a molecular analysis using 7 microsatellite markers and measuring the morphological characteristics of thallus in Kagoshima Bay, Japan. Samples for DNA analysis and morphological measurement were collected from five local populations at 10 sites where annual Z. marina was found to be growing. Morphological characteristics of the Z. marina samples differed among local populations with different environmental conditions. Moreover, pairwise Fst values of microsatellite locus calculated from the five populations ranged from 0.112 to 0.415 (mean=0.273), suggesting that the genetic differentiation among local populations was markedly large. The results of this study indicated that the seed dispersal of annual Z. marina among local populations has rarely occurred for a long time.