北部湾中南部海域3种优势鱼类生态位研究

Ecological niches of three dominant fish species in south-central waters of Beibu Gulf

【目的】比较北部湾中南部海域3种优势鱼类元素组成及其多维化学计量生态位和碳氮稳定同位素营养生态位的差异,系统掌握该海域主要优势鱼类间的关系,同时为北部湾中南部海域渔业资源的可持续开发利用及科学管理提供参考依据。【方法】以2022年4月在北部湾中南部海域采集的3种优势种鱼类[多齿蛇鲻(Saurida tumbil)32尾,大头白姑鱼(Pennahia macrocephalus)34尾,黄带绯鲤(Upeneus sulphureus)33尾]为研究对象,测定其鱼体中20种元素(C、N、P、K、Ca、Na、Mg、Fe、Zn、Mn、Ti、Cr、Co、Ni、Cu、As、Ba、Cd、Pb和Sb)及碳、氮稳定同位素(δ^(13)C和δ^(15)N)含量,通过绘制多维化学计量生态位图和碳氮稳定同位素营养生态位图,比较分析3种优势鱼类元素组成及其生态位的种内和种间差异。【结果】北部湾中南部海域3种优势鱼类元素含量和碳氮稳定同位素含量存在明显的种间及种内差异,其超体积生态位排序为大头白姑鱼(280.97)>多齿蛇鲻(174.45)>黄带绯鲤(98.30),生态位面积排序为多齿蛇鲻(6.63)>黄带绯鲤(4.00)>大头白姑鱼(2.46)。3种优势鱼类种间和种内均存在一定程度的生态位重叠,如种间生态位重叠概率最高的是多齿蛇鲻与大头白姑鱼(14.04%),而种间生态位重叠概率最低的是多齿蛇鲻与黄带绯鲤(1.76%);种内生态位重叠最高的是黄带绯鲤,多齿蛇鲻次之,大头白姑鱼最小。此外,3种优势鱼类多维化学计量超体积生态位与种内差异有关,种内差异越大其超体积生态位越大。【结论】北部湾中南部海域3种优势鱼类元素含量和碳氮稳定同位素含量存在明显的种间及种内差异,多维化学计量生态位和碳氮稳定同位素营养生态位均可用于表征生物的生理特征及功能,但相对于稳定同位素营养生态位,多维化学计量生态位能更好地反映种内差异。因此,后续研究将深入探讨生物多维化学计量生态位的种间及种内差异,如渔业生物个体不同发育阶段的生态位变化,为渔业资源的可持续开发利用及科学管理提供参考依据。

【Objective】The purpose of the study was to compare the elemental composition and the differences in mul-tidimensional stoichiometric and carbon and nitrogen stable isotope trophic ecological niches of three dominant fish spe-cies in south-central Beibu Gulf,so as to systematically understand the relationships between the major dominant fish spe-cies in this area,and to provide reference basis for the sustainable development and utilization as well as the scientific management of the fishery resources in south-central Beibu Gulf.【Method】Three dominant fish species(32 Saurida tum-bil,34 Pennahia macrocephalus and 33 Upeneus sulphureus)collected from the south-central Beibu Gulf in April 2022 were used as study subjects.The contents of 20 elements(C,N,P,K,Ca,Na,Mg,Fe,Zn,Mn,Ti,Cr,Co,Ni,Cu,As,Ba,Cd,Pb and Sb)and stable carbon and nitrogen isotopes(δ^(13)C andδ^(15)N)of the fishes were measured.Com-parative analysis of elemental composition of the three dominant fish species and intraspecific and interspecific differences in their ecological niches was carried out by plotting multidimensional stoichiometric ecological niche maps and carbon and nitrogen stable isotope trophic ecological niche maps.【Result】Obvious interspecific and intraspecific differences in ele-ment contents and carbon and nitrogen stable isotope contents were found among the three dominant fish species in south-central Beibu Gulf,with the ecological niche rankings in terms of hyper volume as P.macrocephalus(280.97)>S.tumbil(174.45)>U.sulphureus(98.30),and the ecological niche area ranked as S.tumbil(6.63)>U.sulphureus(4.00)>P.macro-cephalus(2.46).There was a certain degree of interspecific and intraspecific ecological niche overlaps among these three dominant species.For example,the highest probability of interspecific ecological niche overlap existed between S.tumbil and P.macrocephalus(14.04%),while the lowest probability of interspecific niche overlap was between S.tumbil and U.sulphureus(1.76%).Meanwhile,the highest intraspecific ecological niche overlap was in U.sulphureus,followed by S.tumbil and P.macrocephalus.In addition,the multidimensional stoichiometric hyper volume ecological niche of the three dominant fish species was related to intraspecific variations,the larger the intraspecific differences,the greater the hyper volume niche.【Conclusion】There are obvious interspecific and intraspecific differences in elemental content and carbon and nitrogen stable isotope content of the three dominant fish species in south-central Beibu Gulf.Both multidimensional stoichiometric ecological niche and carbon and nitrogen stable isotope trophic ecological niches can be used to characteri-ze organisms’physiological traits and functions.However,compared with stable isotope trophic ecological niches,multi-dimensional stoichiometric ecological niches can better reflect the intraspecific differences.Thus,the interspecific and in-traspecific differences of multidimensional stoichiometric ecological niches of organisms,including the ecological niche changes of fishery organism individuals at different developmental stages,will be explored in further studies,which can provide reference basis for the sustainable development and utilization as well as the scientific management of fishery re-sources.