- 著者
- Yusuke Kondo Shoma Okada Susumu Ohtsuka Takeshi Hirabayashi Aya Adachi Makoto Urata Sho Toshino Hiroshi Miyake Nanako O. Ogawa Naohiko Ohkouchi
- 出版者
- The Plankton Society of Japan, The Japanese Association of Benthology
- 雑誌
- Plankton and Benthos Research (ISSN:18808247)
- 巻号頁・発行日
- vol.13, no.2, pp.66-74, 2018-05-30 (Released:2018-05-24)
- 参考文献数
- 50
- 被引用文献数
- 1 1
In this study, we investigated the trophic interactions between the Japanese giant box jellyfish, Morbakka virulenta, and fish in the central part of the Seto Inland Sea, western Japan, in autumn and winter. Occurring in the surface waters at nighttime, these cubomedusae, regardless of their size (1.5 to 22.5 cm in bell height), were found to be piscivorous, feeding mainly on the Japanese anchovy, as shown by their stomach contents analysis. This finding was supported by a stable isotopic analysis and by an unchanged cnidome, irrespective of the bell height of medusae. Their nocturnal occurrence near the surface often took place around the slack tide, during which the medusae were foraging with tentacles fully extended. Other associations between the medusae and fish were also observed at this time: presumed commensalism with juvenile Japanese horse mackerel, and predation by black scraper.
- 著者
- Naohiko OHKOUCHI
- 出版者
- The Japan Academy
- 雑誌
- Proceedings of the Japan Academy, Series B (ISSN:03862208)
- 巻号頁・発行日
- vol.99, no.5, pp.131-154, 2023-05-11 (Released:2023-05-11)
- 参考文献数
- 168
- 被引用文献数
- 5
Food web research is rapidly expanding through study of natural fractional abundance of 15N in individual amino acids. This paper overviews the principles of this isotope approach, and from my perspective, reanalyzes applications, and further extends the discussion. It applies kinetic isotope effects that enriches 15N in certain amino acids associated with the metabolic processes, which was clearly demonstrated by observations of both natural ecosystem and laboratory experiments. In trophic processes ‘trophic amino acids’ such as glutamic acid that significantly enrich 15N, whereas ‘source amino acids’ such as phenylalanine and methionine show little 15N enrichment. Through various applications conducted over the years, the principles of the method have shown to operate well and disentangle complex food webs and relevant problems. Applications include food chain length estimate, nitrogen resource assessment, tracking fish migration, and reconstruction of paleodiet. With this approach, considerations of a wide range of classical issues have been reinvigorated, while in the same time, new challenging frontiers are emerging.