This study explored the morphological characteristics and differences of the otoliths in three native species,Schizothorax biddulphi,S.eurystomus and S.curvifrons,in the Yarkand River of the Tarim River,Xinjiang,China...This study explored the morphological characteristics and differences of the otoliths in three native species,Schizothorax biddulphi,S.eurystomus and S.curvifrons,in the Yarkand River of the Tarim River,Xinjiang,China.A total of 93 specimens(27 S.biddulphi,39 S.eurystomus,and 27 S.curvifrons)were analyzed using six basic otolith morphological parameters(OA,R_(max),R_(min),OP,OL,OW)to derive six factors(F_(1),F_(2),F_(3),F_(4),F_(5),F_(6))and seven indices(RO,FF,CI,RE,EL,RR,AR)for morphological assessment.A discriminant analysis incorporating 77 Fourier coefficients of the otoliths revealed distinct morphological differences among the species.A significant power function relationship between otolith morphology and standard length was observed across the species,with R2 values ranging from 0.409 to 0.749.Principal component analysis(PCA)of 7 traditional otolith morphological indicators explained 81.243%of the variance,yielding an overall species discrimination rate of 81.65%.Further PCA of 77 Fourier harmonic values enhanced the discrimination accuracy,with the first 3 components accounting for 77.49%of the total variation and an improved discrimination rate of 100.00%.Cluster analysis resulted in the grouping of S.biddulphi and S.curvifrons together and revealed their association with S.eurystomus,indicating notable morphological distinctions.Both otolith shape indices and elliptical Fourier analysis have been useful in distinguishing the phenotypic units of different fish species.In this study,otolith morphology was applied for the first time to identify Schizothorax species,providing an in-depth description of species distribution and evolutionary history.This study provides a reference for the identification and systematic classification of Schizothorax species and a scientific basis for formulating effective species protection measures,for promoting the sustainable management of species and important habitats.展开更多
Laboratory-reared Schizothorax davidi larvae and juveniles were examined to assess the formation and characteristics of David’s schizothoracin otoliths.Otolith development was observed and their formation period was ...Laboratory-reared Schizothorax davidi larvae and juveniles were examined to assess the formation and characteristics of David’s schizothoracin otoliths.Otolith development was observed and their formation period was verifi ed by monitoring larvae and juveniles of knownage.The results revealed that lapilli and sagittae developed before hatching,and the first otolith increment was identified at 2 days post hatching in both.The shape of lapilli was relatively stable during development compared with that of sagittae;however,growth of four sagittae and lapilli areas was consistent,but the posterior area grew faster than the anterior area and the ventral surface grew faster than the dorsal surface.Similarly,the sum length of the radius of the anterior and posterior areas on sagittae and lapilli were linearly and binomially related to total fish length,respectively.Moreover,daily deposition rates were validated by monitoring knownage larvae and juveniles.The increase in lapilli width was 1.88±0.080 0μm at the ninth increment,which reached a maximum and the decreased gradually toward the otolith edge,whereas that of sagittae increased more slowly.These results illustrate the developmental biology of S.davidi,which will aid in population conservation and fish stock management.展开更多
Fish artificial breeding and release is an important method to restore wild populations of endemic fish species around the world.Schizothorax wangchiachii(SW)is an endemic fish in the upper Yangtze River and is one of...Fish artificial breeding and release is an important method to restore wild populations of endemic fish species around the world.Schizothorax wangchiachii(SW)is an endemic fish in the upper Yangtze River and is one of the most important species for the artificial breeding and release program implemented in the Yalong River drainage system in China.It is unclear how artificially bred SW adapts to the changeable wild environment post-release,after being in a controlled and very different artificial environment.Thus,the gut samples were collected and analyzed for food composition and microbial 16S rRNA in artificially bred SW juveniles at day 0(before release),5,10,15,20,25,and 30 after release to the lower reaches of the Yalong River.The results indicated that SW began to ingest periphytic algae from the natural habitat before day 5,and this feeding habit is gradually stabilized at day 15.Prior to release,Fusobacteria are the dominant bacteria in the gut microbiota of SW,while Proteobacteria and Cyanobacteria generally are the dominant bacteria after release.The results of microbial assembly mechanisms illustrated that deterministic processes played a more prominent role than stochastic processes in the gut microbial community of artificially bred SW juveniles after releasing into the wild.Overall,the present study integrates the macroscopic and microscopic methods to provide an insight into the food and gut microbial reorganization in the released SW.This study will be an important research direction to explore the ecological adaptability of artificially bred fish after releasing into the wild.展开更多
基金Supported by the National Natural Science Foundation of China(No.31360635)the Tianshan Talent Training Project of Xinjiang(No.2023 TSYCCX 0128)the Science and Technology Public Relations Planning in Key Fields of the XPCC Science and Technology Bureau(No.2022 DB 019)。
文摘This study explored the morphological characteristics and differences of the otoliths in three native species,Schizothorax biddulphi,S.eurystomus and S.curvifrons,in the Yarkand River of the Tarim River,Xinjiang,China.A total of 93 specimens(27 S.biddulphi,39 S.eurystomus,and 27 S.curvifrons)were analyzed using six basic otolith morphological parameters(OA,R_(max),R_(min),OP,OL,OW)to derive six factors(F_(1),F_(2),F_(3),F_(4),F_(5),F_(6))and seven indices(RO,FF,CI,RE,EL,RR,AR)for morphological assessment.A discriminant analysis incorporating 77 Fourier coefficients of the otoliths revealed distinct morphological differences among the species.A significant power function relationship between otolith morphology and standard length was observed across the species,with R2 values ranging from 0.409 to 0.749.Principal component analysis(PCA)of 7 traditional otolith morphological indicators explained 81.243%of the variance,yielding an overall species discrimination rate of 81.65%.Further PCA of 77 Fourier harmonic values enhanced the discrimination accuracy,with the first 3 components accounting for 77.49%of the total variation and an improved discrimination rate of 100.00%.Cluster analysis resulted in the grouping of S.biddulphi and S.curvifrons together and revealed their association with S.eurystomus,indicating notable morphological distinctions.Both otolith shape indices and elliptical Fourier analysis have been useful in distinguishing the phenotypic units of different fish species.In this study,otolith morphology was applied for the first time to identify Schizothorax species,providing an in-depth description of species distribution and evolutionary history.This study provides a reference for the identification and systematic classification of Schizothorax species and a scientific basis for formulating effective species protection measures,for promoting the sustainable management of species and important habitats.
基金Supported by the Double Branch Plan of Sichuan Agricultural University(Nos.03571421,03571779)
文摘Laboratory-reared Schizothorax davidi larvae and juveniles were examined to assess the formation and characteristics of David’s schizothoracin otoliths.Otolith development was observed and their formation period was verifi ed by monitoring larvae and juveniles of knownage.The results revealed that lapilli and sagittae developed before hatching,and the first otolith increment was identified at 2 days post hatching in both.The shape of lapilli was relatively stable during development compared with that of sagittae;however,growth of four sagittae and lapilli areas was consistent,but the posterior area grew faster than the anterior area and the ventral surface grew faster than the dorsal surface.Similarly,the sum length of the radius of the anterior and posterior areas on sagittae and lapilli were linearly and binomially related to total fish length,respectively.Moreover,daily deposition rates were validated by monitoring knownage larvae and juveniles.The increase in lapilli width was 1.88±0.080 0μm at the ninth increment,which reached a maximum and the decreased gradually toward the otolith edge,whereas that of sagittae increased more slowly.These results illustrate the developmental biology of S.davidi,which will aid in population conservation and fish stock management.
基金The authors thank the Fish Reproduction Station of Jinping-Guandi,China for providing the place for dissecting experiments.This study was supported by grants from the Yalong River Hydropower Development Company,Ltd.(No.YLDC-ZBA-2018116)the National Natural Science Foundation of China(No.31900373).We thank Megan Price for her help with language editing.
文摘Fish artificial breeding and release is an important method to restore wild populations of endemic fish species around the world.Schizothorax wangchiachii(SW)is an endemic fish in the upper Yangtze River and is one of the most important species for the artificial breeding and release program implemented in the Yalong River drainage system in China.It is unclear how artificially bred SW adapts to the changeable wild environment post-release,after being in a controlled and very different artificial environment.Thus,the gut samples were collected and analyzed for food composition and microbial 16S rRNA in artificially bred SW juveniles at day 0(before release),5,10,15,20,25,and 30 after release to the lower reaches of the Yalong River.The results indicated that SW began to ingest periphytic algae from the natural habitat before day 5,and this feeding habit is gradually stabilized at day 15.Prior to release,Fusobacteria are the dominant bacteria in the gut microbiota of SW,while Proteobacteria and Cyanobacteria generally are the dominant bacteria after release.The results of microbial assembly mechanisms illustrated that deterministic processes played a more prominent role than stochastic processes in the gut microbial community of artificially bred SW juveniles after releasing into the wild.Overall,the present study integrates the macroscopic and microscopic methods to provide an insight into the food and gut microbial reorganization in the released SW.This study will be an important research direction to explore the ecological adaptability of artificially bred fish after releasing into the wild.
