Inequality in the distribution of Cs contamination within freshwater fish bodies and its affecting factors.

Contamination of freshwater fishes with Cs remains as a serious problem in Japan, nearly 10 years after the Fukushima nuclear power plant accident, but there is limited information on the distribution of Cs contamination in fish bodies. The Cs distribution can be used for the estimation of internal radiation exposure through the consumption of fish and for the dose estimation of fish themselves. In this study, the Cs distribution in the bodies of 8 freshwater fish species was investigated as percentages of total body burden for fish inhabiting Lake Inba.

Molecular Evidence for the Expansion of the Asian Cryptic Invader Hediste diadroma (Nereididae: Annelida) into the Northeast Pacific Habitats of the Native H. limnicola.

We used previously established molecular methods to determine how far the Asian invader nereidid worm Hediste diadroma has spread into northeast Pacific estuaries that are inhabited by the native congener H. limnicola. Further, we analyzed the mitochondrial DNA of 702 Hediste specimens collected from 27 estuaries along 1,350 km of coastline in Washington, Oregon, and California, USA, to distinguish between the morphologically indistinguishable immature stages of these two species.

Genetic population structure of local populations of the endangered saltmarsh sesarmid crab Clistocoeloma sinense in Japan.

During recent decades, over 40% of Japanese estuarine tidal flats have been lost due to coastal developments. Local populations of the saltmarsh sesarmid crab Clistocoeloma sinense, designated as an endangered species due to the limited suitable saltmarsh habitat available, have decreased accordingly, being now represented as small remnant populations. Several such populations in Tokyo Bay, have been recognised as representing distributional limits of the species.

Phylogenetic relationships between the tideland snails Batillaria flectosiphonata in the Ryukyu Islands and B. multiformis in the Japanese Islands.

Phylogenetic relationships between two sibling species of Japanese tideland snails, namely, Batillaria multiformis from the Japanese Islands and B. flectosiphonata from the Ryukyu Islands, were analyzed on the basis of the nucleotide sequences of the mitochondrial gene for cytochrome oxidase I. Populations of B.