2024-03-28T23:32:15Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/684012022-11-17T02:08:08Zhdl_2115_20049hdl_2115_141Nitrogen stable isotopes reveal age-dependent dietary shift in the Japanese scallop Mizuhopecten yessoensisAya, Frolan A.Kudo, IsaoAgeanimalscarbon-13diet shiftfoodisotope ecologynitrogen-15scallopssizezooplankton660Ontogenetic niche shifts in diet are a consequence of changes in body size or resource partitioning between age classes. To better resolve the feeding patterns of the Japanese scallop Mizuhopecten yessoensis, we examined the relative importance of age and size in the diet of this species using stable isotope ratios of carbon (C-13) and nitrogen (N-15) from 2006 to 2009. Contribution of food sources was quantified using an isotope mixing model by comparing the muscle tissue isotope ratios to those of suspended particulate organic matter (SPOM) and their zooplankton prey (e.g. micro- and meso-zooplankton). Unlike the C-13 values, which remained constant with age and size, muscle N-15 values were more positively correlated with age accounting for 69% of variations than size with only 46%. Increasing N-15 values with age suggested that shifts in diet from SPOM to micro- and meso-zooplankton occurred during ontogeny in M. yessoensis. Results of the isotope mixing model indicated that SPOM contribution to scallop's diet decreased from 68 to 8% while those of zooplankton increased from 15 to 50% with increasing age. This study concludes that age-related dietary shift explains the enrichment of N-15, as a result of predation on zooplankton by M. yessoensis.Taylor & FrancisJournal Articleapplication/pdfhttp://hdl.handle.net/2115/68401https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/68401/1/Kudo.pdf1025-6016AA11072326Isotopes in environmental and health studies53180902017-03enginfo:pmid/27225746info:doi/10.1080/10256016.2016.1186024This is an Accepted Manuscript of an article published by Taylor & Francis in Isotopes in Environmental and Health Studies on March 2017, available online: http://www.tandfonline.com/10.1080/10256016.2016.1186024.author