Concentrations of persistent organic pollutants in masu salmon, Oncorhynchus masou

The levels of persistent organic pollutants (POPs) were analyzed in muscle, liver and gills of masu salmon caught in northern Japan. Liver is known to be a major pool site for POPs but there is not much information regarding accumulation of POPs in gills. The salmon were caught at the end of the feeding migration, and the average gonadosomatic index of masu salmon was 0.51 +/- 0.16. The total amount of POPs (microg) accumulated in each organ was calculated in order to compare the accumulation potential of each organ. Even though the liver comprises only 1.8%-2.32% of the whole body mass it accumulated 16% +/- 8.6% of the total POPs. Similarly, gills comprise only 1.4%-2.1% of the body mass but accumulated 9.1% +/- 3.8% of the total POPs. Conversely, muscle comprises 72%-78% of the body mass and it accumulated 75% +/- 12% of the total POPs. These results suggest that the gills, in addition to the liver, are an important site for the pooling of high levels of POPs at the end of the feeding migration.