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

Representative Organization: Tohoku University

2013/04/01 - 2014/03/31

Touni Bay and Okirai Bay, Iwate Prefecture

Field survey

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 markers.

1. Pacific abalone We identified the frequency and number of alleles before the tsunami, which will be used as the control data for comparative examination of the alleles after the tsunami. 2. Japanese sea cucumber No significant difference was observed in the Hardy?Weinberg equilibrium before and after the tsunami. However, after the tsunami, the number of alleles was relatively lower than that before the tsunami. We believe that the decrease in the genetic diversity after the tsunami was due to a decrease in the population because of tsunami damage. 3. Japanese sea urchin For this species, we identified an effective msDNA locus for future analysis. Four loci were examined from which one locus that indicated extremely high variability was selected. In addition, we obtained basic data for this locus, including the allele frequency. In the future, we will continue to analyze the genetic population structures of the above three species before and after the tsunami by using msDNA markers.