An index of relative importance(IRI) was employed to screen for dominant fish in the waters surrounding the Taishan Islands, China, using data from four seasonal trawl surveys undertaken between 2012 and 2013. Niche b...An index of relative importance(IRI) was employed to screen for dominant fish in the waters surrounding the Taishan Islands, China, using data from four seasonal trawl surveys undertaken between 2012 and 2013. Niche breadth and niche overlap were measured using the Feinsinger and Morisita-Horn indices, respectively, and the characteristics and seasonal variations in the niches of dominant fish were assessed via non-metric multidimensional scaling(NMDS) and cluster analysis. A total of 80 fish species, including 16 dominant species, were recorded. Only A mblychaeturichthys hexanema was dominant in all seasons. According to niche breadth values and NMDS, the 16 dominant species were grouped into the following three types:(1) wide niche breadth species, including Cynoglossus macrolepidotus, A. hexanema, and Trypauchen vagina, among others;(2) medium niche breadth species, including Setipinna taty and Johnius belangerii; and(3) narrow niche breadth species, including A trobucca nibe and Coilia mystus. Most species with a wider niche breadth were demersal fish with a lower swimming capability and even distribution. The niche breadth of migrating fish was narrower than that of settled fish. At a given spatial scale, fish with stronger swimming capabilities had a narrower niche breadth. Niche overlap, which is associated with niche specialization, ranged from 0.000 to 0.886 and had an annual mean value of 0.314. In summer and autumn, niche overlap was relatively high within species of the Sciaenidae family and within species of the Gobiidae in autumn. Dif ferences in thermophily, feeding habits, food organism abundance/distribution and predator-prey relationships af fected the niche overlap of fish in this area. Cluster analysis revealed that species with the narrowest niche breadth and lowest niche overlap values usually displayed lower aggregation and greater distribution dif ferences compared with other species.展开更多
This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weiha...This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weihai, China. Samples were collected using two types of plankton net （Model I and Model II） for different-sized copepods. The number of taxon was calculated from the data of both the net types, while the copepod abundance was done using the samples from Model II only. Sixteen species of planktonic copepods, including 5 dominant species, were recorded. Results reveal that Oithona similis was the first dominant species from March to June, and was replaced by Paracalanus parvus in September; both dominated the copepod community in January. Acartia hongi was the second dominant species from March to September. Centropages abdominalis was the third dominant species from March to June, and was replaced by O. sirnilis in September and Corycaeus aJfinis in January. C. affinis was the fourth dominant species in September. Population density of the dominant copepods was compared with that of other similar regions. We found that the dominant species were mostly small copepods （〈1 mm） except for adult Centrapages abdominalis. Seasonal variation in prosome length of O. similis, C. abdominalis, and C. affinis, and their copepodites were studied for the first time in China. For P. parvus and A. hongi, seasonal trends in prosome length variation were similar with those in Jiaozhou Bay, Yellow Sea, Qingdao, China, in a similar temperate domain. The results are helpful for future calculation of copepod biomass and production, and for investigation of the relationship between copepods and fish resources.展开更多
基金Supported by the National Natural Science Foundation of China(No.41106073)the Technology R&D Program of Fujian Provincial Department of Ocean and Fisheries(No.2012013)
文摘An index of relative importance(IRI) was employed to screen for dominant fish in the waters surrounding the Taishan Islands, China, using data from four seasonal trawl surveys undertaken between 2012 and 2013. Niche breadth and niche overlap were measured using the Feinsinger and Morisita-Horn indices, respectively, and the characteristics and seasonal variations in the niches of dominant fish were assessed via non-metric multidimensional scaling(NMDS) and cluster analysis. A total of 80 fish species, including 16 dominant species, were recorded. Only A mblychaeturichthys hexanema was dominant in all seasons. According to niche breadth values and NMDS, the 16 dominant species were grouped into the following three types:(1) wide niche breadth species, including Cynoglossus macrolepidotus, A. hexanema, and Trypauchen vagina, among others;(2) medium niche breadth species, including Setipinna taty and Johnius belangerii; and(3) narrow niche breadth species, including A trobucca nibe and Coilia mystus. Most species with a wider niche breadth were demersal fish with a lower swimming capability and even distribution. The niche breadth of migrating fish was narrower than that of settled fish. At a given spatial scale, fish with stronger swimming capabilities had a narrower niche breadth. Niche overlap, which is associated with niche specialization, ranged from 0.000 to 0.886 and had an annual mean value of 0.314. In summer and autumn, niche overlap was relatively high within species of the Sciaenidae family and within species of the Gobiidae in autumn. Dif ferences in thermophily, feeding habits, food organism abundance/distribution and predator-prey relationships af fected the niche overlap of fish in this area. Cluster analysis revealed that species with the narrowest niche breadth and lowest niche overlap values usually displayed lower aggregation and greater distribution dif ferences compared with other species.
基金Supported by the National Natural Science Foundation of China(No.41106133)the Shandong University Independent Innovation Foundation(No.2011ZRYQ005)the Program of Academy of Marine Research in Weihai(No.000041342080)
文摘This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weihai, China. Samples were collected using two types of plankton net （Model I and Model II） for different-sized copepods. The number of taxon was calculated from the data of both the net types, while the copepod abundance was done using the samples from Model II only. Sixteen species of planktonic copepods, including 5 dominant species, were recorded. Results reveal that Oithona similis was the first dominant species from March to June, and was replaced by Paracalanus parvus in September; both dominated the copepod community in January. Acartia hongi was the second dominant species from March to September. Centropages abdominalis was the third dominant species from March to June, and was replaced by O. sirnilis in September and Corycaeus aJfinis in January. C. affinis was the fourth dominant species in September. Population density of the dominant copepods was compared with that of other similar regions. We found that the dominant species were mostly small copepods （〈1 mm） except for adult Centrapages abdominalis. Seasonal variation in prosome length of O. similis, C. abdominalis, and C. affinis, and their copepodites were studied for the first time in China. For P. parvus and A. hongi, seasonal trends in prosome length variation were similar with those in Jiaozhou Bay, Yellow Sea, Qingdao, China, in a similar temperate domain. The results are helpful for future calculation of copepod biomass and production, and for investigation of the relationship between copepods and fish resources.
