Stable isotopes are increasingly used to investigate seasonal migrations of aquatic organisms. This study employed stable isotopes (delta C-13 and delta N-15) for Coilia nasus from the lower Yangtze River and the adja...Stable isotopes are increasingly used to investigate seasonal migrations of aquatic organisms. This study employed stable isotopes (delta C-13 and delta N-15) for Coilia nasus from the lower Yangtze River and the adjacent East China Sea to distinguish different ecotypic groups, ascertain trophic nutrition positions, and reflect environmental influences on C. nasus. delta C-13 signatures of C. nasus sampled from Zhoushan (ZS), Chongming (CM), and Jingjiang (JJ) waters were significantly higher than those from the Poyang Lake (PYL) (P < 0.05). By contrast, delta N-15 signatures of C. nasus in ZS, CM, and JJ groups were significantly lower than those in PYL group (P < 0.05). Basing on delta C-13 and delta N-15 signatures, we could distinguish anadromous (ZS, CM, and JJ) and non-anadromous (PYL) groups. The trophic level (TL) of anadromous C. nasus ranged from 2.90 to 3.04, whereas that of non-anadromous C. nasus was 4.38. C. nasus occupied the middle and top nutrition positions in the marine and Poyang Lake food webs, respectively. C. nasus in Poyang Lake were significantly more enriched in delta N-15 but depleted in delta C-13, suggesting that anthropogenic nutrient inputs and terrigenous organic carbon are important to the Poyang Lake food web. This study is the first to apply delta N-15 and delta C-13 to population assignment studies of C. nasus in the Yangtze River and its affiliated waters. Analysis of stable isotopes (delta N-15 and delta C-13) is shown to be a useful tool for discriminating anadromous and non-anadromous C. nasus.展开更多
The rapid development of molecular phylogenetic analysis has provided a new path to investigate the tempo of evolution.In this work,a rather complete molecular phylogeny of the East Asian gobionid fishes was construct...The rapid development of molecular phylogenetic analysis has provided a new path to investigate the tempo of evolution.In this work,a rather complete molecular phylogeny of the East Asian gobionid fishes was constructed based on mtDNA cytochrome b gene sequences.Molecular clock analysis was then applied to investigate the speciation tempo of this group.The phylogenetic analysis revealed four major groups that were in agreement with previous studies.Lineage numbers plotted over time indicate that gobionid lineages increased in an exponential mode with the equation expressed as y=87.562×e 0.1141x,where y is the number of lineages and x represents the geological time,and 0 < x ≤ 30,1≤ y ≤ 65.The speciation rate of gobionid fishes calculated by LASER program was inconstant.Peaks of speciation were identified and found approximately to be coincident with East Asian geological events,such as uplifts of the Tibetan plateau and formation of the monsoon system.展开更多
基金financially supported by the Special Fund for Agro-scientific Research in the Public-Interest(Grant No.201203065)the National Natural Science Foundation of China(Nos.31172407+1 种基金1472280)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20123104110006)
文摘Stable isotopes are increasingly used to investigate seasonal migrations of aquatic organisms. This study employed stable isotopes (delta C-13 and delta N-15) for Coilia nasus from the lower Yangtze River and the adjacent East China Sea to distinguish different ecotypic groups, ascertain trophic nutrition positions, and reflect environmental influences on C. nasus. delta C-13 signatures of C. nasus sampled from Zhoushan (ZS), Chongming (CM), and Jingjiang (JJ) waters were significantly higher than those from the Poyang Lake (PYL) (P < 0.05). By contrast, delta N-15 signatures of C. nasus in ZS, CM, and JJ groups were significantly lower than those in PYL group (P < 0.05). Basing on delta C-13 and delta N-15 signatures, we could distinguish anadromous (ZS, CM, and JJ) and non-anadromous (PYL) groups. The trophic level (TL) of anadromous C. nasus ranged from 2.90 to 3.04, whereas that of non-anadromous C. nasus was 4.38. C. nasus occupied the middle and top nutrition positions in the marine and Poyang Lake food webs, respectively. C. nasus in Poyang Lake were significantly more enriched in delta N-15 but depleted in delta C-13, suggesting that anthropogenic nutrient inputs and terrigenous organic carbon are important to the Poyang Lake food web. This study is the first to apply delta N-15 and delta C-13 to population assignment studies of C. nasus in the Yangtze River and its affiliated waters. Analysis of stable isotopes (delta N-15 and delta C-13) is shown to be a useful tool for discriminating anadromous and non-anadromous C. nasus.
基金supported by the National Natural Science Foundation of China (Grant No.40432003)the Cypriniformes Tree of Life (CToL) project funded by the National Science Foundation of USA (Grant No. EF-0431326)
文摘The rapid development of molecular phylogenetic analysis has provided a new path to investigate the tempo of evolution.In this work,a rather complete molecular phylogeny of the East Asian gobionid fishes was constructed based on mtDNA cytochrome b gene sequences.Molecular clock analysis was then applied to investigate the speciation tempo of this group.The phylogenetic analysis revealed four major groups that were in agreement with previous studies.Lineage numbers plotted over time indicate that gobionid lineages increased in an exponential mode with the equation expressed as y=87.562×e 0.1141x,where y is the number of lineages and x represents the geological time,and 0 < x ≤ 30,1≤ y ≤ 65.The speciation rate of gobionid fishes calculated by LASER program was inconstant.Peaks of speciation were identified and found approximately to be coincident with East Asian geological events,such as uplifts of the Tibetan plateau and formation of the monsoon system.
