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| Takashi Minami | |
| Research Coordinator of Oceanography and Resources | |
| Japan Sea National Fisheries Research Institute, | |
| Fisheries Agency. | |
| Suido-cho 1-5939-22, Niigata, Niigata, 951-8121, | |
| Japan. | |
| Tel: +81-25-228-0546 Fax: +81-25-224-0950 | |
| E-mail: mtakashi@jsnf.affrc.go.jp |
6,642,000 Yen
(FY 1999; 3,442,000 Yen)
Food chain structure in the benthic communities were studied by the field survey carried out in the offshore region of San-in district and Yamato Bank, the Sea of Japan. Many kinds of organisms such as snow crab, pink shrimp, flatfishes, eelpouts and sculpin were obtained by the bottom trawl, and stomach contents of the dominant species of the benthic community were analyzed for estimating the predator-prey relationships. Detritus is important food sources in offshore bottom food chain, and small shrimp, gammarus, small squid are also play as food organisms in the communities.
Trophic levels were estimated by means of stable isotope ratios (15N concentration). There were differences in the 15N values of individual species within benthic organisms. Trophic levels are markedly higher in eelpout species which feed on fish and crustacean in San-in region, whereas in Yamato Bank bottom community, the large shrimps which fed on detritus show higher values in 15N concentration.
food chain, bottom fish, offshore, bioaccumulation