Genetic population structures of fishing resources (abalone, sea cucumber, and sea urchin) off the coast of southern Iwate Prefecture, Japan

Representative Organization: Tohoku University

2014/04/01 - 2015/03/31
Sampling: several times in a year, analysis :any time.

Touni Bay and Okirai Bay, Iwate Prefecture

Others(Collection in the field and analysis in the laboratory)

Pacific abalone Haliotis discus hannai, Japanese sea cucumber Apostichopus japonicus, and Japanese sea urchin Strongylocentrotus nudus are economically important marine products in Sanriku Coast, Iwate, Japan. Since fishing of the above species is dependent on their natural resources, it is important to examine the influence of the tsunami that hit the Pacific Coast after the Tohoku Earthquake in 2011, on natural marine resources. We assume that the tsunami caused a reduction in the number of individuals in the parental population, which in turn caused a reduction in the genetic diversity. In this study, to monitor the reduction in genetic diversity, which could cause population decline, we compared the genetic population structures of the above three species before and after tsunami using microsatellite (ms) DNA and mitochondrial (mt) DNA markers.

We conducted a population genetics study on Japanese sea cucumber Apostichopus japonicus, Pacific abalone Haliotis discus hannai, and Japanese sea urchin Strongylocentrotus nudus using microsatellite and mitochondrial DNA markers. In the aftermath of the tsunami, it is considered that the population of sea cucumbers does not experience extensive inbreeding or immigration of large amounts of new genetic material from a different population. However, the number of alleles and haplotype diversity in the population of Japanese sea cucumber was relatively lower than that in the population before the tsunami. These results suggested that the decrease in genetic diversity after the tsunami was due to a decrease in the population size caused by tsunami-generated damage. Three years after the tsunami, the parental population of the Pacific abalone did not exhibit a strong bottle neck effect. In contrast, an excess of homozygotes was observed in the sea urchin population, indicating the tendency toward inbreeding. In the future, we will continue analyzing the genetic population structure of the above three species before and after the tsunami.

FY2014 Genetic population structures of fishing resources (abalone, sea cucumber, and sea urchin) off the coast of southern Iwate Prefecture, Japan