Sulfur, Carbon, and Nitrogen Stable Isotope Ratios in Soft Tissues and Trophic Relationships of Fish from the Near-Shore Waters of the Peter the Great Bay in the Sea of Japan

Stable isotope ratios of sulfur (S-34/S-32), carbon (C-13/C-12), and nitrogen (N-15/N-14) were analyzed in the soft tissues of 12 common species of fish from the near-shore waters of the Peter the Great Bay in the Sea of Japan. The average delta C-13 values of individual species varied from -20.7% for planktivorous fish to -16.8% for benthivorous fish, reflecting the growing relative contribution of benthic primary producers to fish nutrition. The majority of the various species representatives studied can be assigned to one trophic level, as indicated by their narrow range of delta N-15 values (9.9 to 12.6 parts per thousand). Large interspecific variations were found in the sulfur stable isotope ratios of fish (the mean delta S-34 values ranged from 11.2 to 19.5 parts per thousand). This is the result of the different contributions to fish nutrition of infaunal invertebrates that are depleted in S-34 due to the microbial food chain of the bottom sediments.