Seasonal succession of zooplankton in Sansha Bay,Fujian

根据2010年6月—2011年5月三沙湾海域5个航次海洋综合调查资料,对三沙湾浮游动物种群特征进行分析,并与我国不同纬度海湾生态类群结构进行比较。探讨三沙湾海域浮游动物生态类群季节变化特征及其受水团季节变化的影响。研究结果表明:4月和5月三沙湾海域主要受到浙闽沿岸流影响,生物多样性H'指数分别为2.03和2.02;种类数分别仅为17种和19种,明显低于6月、8月和10月;浮游动物生态类群以暖温带近海种为主;优势种种类数少,单一优势种优势性明显,4月中华哲水蚤丰度占浮游动物总丰度的65.03%;群落结构特征与同期我国长江口浮游动物区系特征相似。6月三沙湾海域受到浙闽沿岸流和台湾暖流共同影响,同时因闽北雨季导致大量大陆径流汇入,使得该月浮游动物种群结构复杂,生物多样性指数和种类数全年最高,为3.12和45种,与5月相比,种类更替明显,物种更替率为69.39%;亚热带近海种丰度百分比最高(73.03%),亚热带外海种种类数百分比次之(48.89%),是海域浮游动物生态类群由以暖温带近海种为主向以亚热带外海种为主的过渡时期。8月和10月浙闽沿岸流消失,三沙湾海域受台湾暖流控制,海水温度和盐度升高,生物多样性指数和种类数均略低于6月;生态类群结构以亚热带外海种为主;优势种特征表现为种类数多而各个优势种丰度较低;浮游动物群落结构特征与南海北部海域浮游动物组成极为相似。The semi-enclosed coastal waters of northeastern Fujian(Sansha Bay) are an important natural spawning ground for the large yellow croaker(Larimichthys crocea) in China.The yellow croaker is an important species for Chinese fisheries,and depends on a healthy zooplankton population.In this study,the seasonal succession of zooplankton in Sansha Bay was described and its relationship to the currents from the open sea was analyzed.Sampling was carried out in June,August and October 2010,and in April and May 2011.Seasonal changes in the zooplankton community structure were strongly influenced by the coastal current and the Taiwan Warm Current as well as an influx of freshwater from the mainland.A total number of 71 species of zooplankton were identified,which consisted of 19.72% warm temperate nearshore species,30.99% subtropical nearshore species and 47.89% subtropical offshore species.In April and May,influenced by the coastal current,the water temperature and salinity were both low,which induced a bottoming-out in the diversity index(H′)(2.03 and 2.02,respectively) as well as the number of species(17 and 19,respectively).The zooplankton fauna was exclusively of the warm temperate nearshore type,especially in April.Both the species number and abundance of warm temperate nearshore species were high(76.47% and 96.28%,respectively).Calanus sinicus,one of only a few dominant species in April,comprised 65.03% of the total abundance of all zooplankton.The simple structure of the zooplankton fauna comprised only a few species and with a high contribution made by each of the dominant species in this period was similar to characteristics noted in the warm-temperate water area north of the Yangtze River.During the June rainy season,a high diversity index(3.12) and species number(45) were recorded owing to the impact of the coastal current,the Taiwan Warm Current and a high volume of fresh water input.These were the most influential factors on the complex taxonomic structure and eco-group composition of the zooplankton fauna.June also displayed the highest species turnover rate,reaching up to 69.39%,compared with other months.The dominate eco-group type changed rapidly from warm temperate and subtropical nearshore species to subtropical offshore species in this month.Subtropical nearshore species comprised the highest proportion of species(73.03%).Subtropical offshore species contributed 48.89% of the overall abundance.After the rainy season,in August and October,there was a slight decrease in diversity index and species number,and the water temperature and salinity increased sharply owing to the strong affect of the Taiwan Warm Current.The zooplankton community was dominated(in terms of species numbers and density) by highly diversified subtropical offshore species.Its proportion of species number and abundance in August were 57.14% and 59.94%,respectively,and species number proportion was 57.58% in October.The community structure had many more dominant species than in April and May,of which the vast majority were subtropical offshore species.The characteristics of the zooplankton community in Sansha Bay were similar to those in the subtropical water areas of the South China Sea.国家自然科学基金项目(40776077); 国家重点基础研究发展计划(973计划)项目(2010CB428705

Comparison of zooplankton communities inside and outside the Hangzhou Bay in autumn

本文比较了杭州湾湾外海域(122.10°–122.58°E,30.54°–30.93°N)和湾内不同海域(北岸东侧:121.67°–121.87°E,30.68°–30.83°N;南岸东侧:121.60°–121.85°E,29.95°–30.24°N;北岸西侧:121.31°–121.56°E,30.58°–30.77°N)秋季浮游动物的群落组成、累积优势度曲线以及多样性指数(H')等群落结构特征,并进行了差异性分析。结果表明:湾外海域的群落组成与湾内海域的3个群落之间均有较大的差异。湾外海域的群落I是以中华假磷虾(Pseudeuphausia sinica)等近海种、背针胸刺水蚤(Centropages dorsispinatus)等沿岸低盐种为主,其次是外海种。湾内南岸东侧海域的群落II主要以左突唇角水蚤(Labidocera sinilobata)等沿岸低盐种为主,近海种次之。湾内北岸东侧海域的群落III是以真刺唇角水蚤(Labidocera euchaeta)等沿岸低盐种、虫肢歪水蚤(Tortanus vermiculus)等河口半咸水种组成的混合群落。湾内北岸西侧海域群落IV是以虫肢歪水蚤为代表的河口半咸水种为主的群落。总的说来,这一水域向西和向北方向出现更低盐度适应性的群落。从累积优势度曲线来看,湾外海域群落I与湾内北岸东侧群落III的累积优势度上升趋势均相对平缓,但群落III的初始累积优势度略高于群落I;而与群落I相比,湾内南岸东侧的群落II与北岸西侧的群落IV的初始累积优势度均很高。湾外海域群落I的初始累积优势度较低,显示出群落I的优势种较多,而单一优势种优势度低于湾内3个群落。方差分析结果表明:湾外海域的浮游动物多样性指数与湾内3个海域均有极显著差异(P0.05)。说明湾外浮游动物群落的多样性高于湾内海域。湾内外海域浮游动物群落特征之间有较大差异,其主要原因是影响各自群落的主导水团明显不同。We analyzed and compared the differences in community composition,K-dominance curves and diversity index(H') of zooplankton community structure characteristics inside and outside the Hangzhou Bay in autumn(outside the bay: 122.10°–122.58° E,30.54°–30.93° N; inside the bay: the east area of north: 121.67°–121.87° E,30.68°–30.83° N; the east area of south:121.60°–121.85° E,29.95°–30.24° N; the west area of north: 121.31°–121.56° E,30.58°–30.77° N).Results indicated that there were large differences between the community composition of zooplankton outside the bay and those in the three areas inside the bay.The area outside the bay(community I) was composed of nearshore species such as Pseudeuphausia sinica and nearshore low-salinity species such as Centropages dorsispinatus,followed by offshore species.Community II(the eastern area of south Hangzhou Bay) was composed of nearshore low-salinity species such as Labidocera sinilobata,followed by nearshore species.Community III(the eastern area of north Hangzhou Bay) was mixed with nearshore low-salinity species such as Labidocera euchaeta and estuarine brackish-water species such as Tortanus vermiculus.Community IV(the western area of north Hangzhou Bay) was characterized by the dominant species,Tortanus vermiculus of estuarine brackish-water species that had the highest proportion,which was different from the community I.Generally,the community with lower salinity adaptability appeared in the western and northern areas.According to K-dominance curves,the dominance curves of community I and community III were quite gentle.In addition,the initial cumulative dominance of community III was higher than that of community I.Compared with community I,the initial cumulative dominance of community II and community IV were far higher than that of community I.The initial cumulative dominance of community I(outside the bay) was particularly low,which indicated that there were many types of dominant species in community I,and the dominance of single dominant species was lower than those communities inside the bay.Results of variance analysis indicated that there were highly significant differences between the diversity index of zooplankton outside the bay and those in the other three waters inside the bay(P 0.05).This showed that the diversity index of zooplankton outside the bay was higher than those of the communities inside the bay.The influence of different water masses resulted in zooplankton community differences in the inner and outer waters of the bay.国家自然科学基金(41176131);; 海洋公益性行业科研专项经费项目(201305027

Characteristics of zooplankton communities off the Feiyun River estuary

根据2010—2011年在飞云江附近海域(27°46'n—27°75'n,120°66'E—121°01'E)秋、冬、春3个季节的调查资料,分析了浮游动物的种类组成及多样性分布、总丰度的平面分布和季节变化及其与水团变化的关系。结果表明:飞云江口附近水域秋、冬、春三季共鉴定出浮游动物60种,分属于11大类;秋季检出浮游动物9大类42种,冬季检出5大类20种,春季检出8大类34种;调查水域浮游动物丰度在秋、冬之间和冬、春之间有较大变化,秋、冬、春三季浮游动物平均丰度分别为221.69、19.52和137.50 Ind·M-3;秋、冬、春季种类数近岸较少,外海较多;三季中,秋季浮游动物SHAnnOn多样性指数最高,高值区位于调查水域的东南部,其次为春季,最高值出现在飞云江口外海域,冬季为三季最低,最高值出现在调查水域北侧岛群之间;中华哲水蚤(CAlAnuS SInICuS)是冬、春季影响总丰度变化最主要的种类,秋季总丰度变化主要受针刺拟哲水蚤(PArACAlAnuS ACulEATuS)和百陶箭虫(SAgITTA bEdOTI)影响;各水团随季节变化此消彼长共同作用于研究水域,对该水域浮游动物数量分布和群落组成产生相应的影响。Based on three oceanographic surveys conducted off the Feiyun River estuary( 27°46'-27°75'N,120°66'-121°01'E) in November 2010( autumn),January 2011( winter) and May2011( spring),the species composition,Shannon diversity,abundance,horizontal distribution,and seasonal variation of zooplankton were investigated,and their relationship to seasonal variation of water masses was also examined.A total of 60 species belonging to 11 groups were identified,including 42 species belonging to 9 groups in autumn,20 species belonging to 5 groups in winter and 34 species belonging to 8 groups in spring.The abundance of zooplankton was highest in autumn( 221.69 ind·m-3),least in winter( 19.52 ind·m-3),and intermediate in spring( 137.50 ind·m-3).Spatially,the zooplankton was most numerous in the offshore water.The Shannon diversity of zooplankton was highest in autumn followed by spring and winter.The high value area of diversity was situated in the southeast of investigation waters( autumn),in the outer area of Feiyun River estuary( spring) and among archipelago in the north( winter),respectively.In winter and spring,Calanus sinicus was the predominant which determined the distribution pattern of zooplankton abundance.In autumn,Paracalanus aculeatus and Sagitta bedoti exerted the greatest influence on the distribution of zooplankton abundance.Furthermore,the abundance and community composition of zooplankton was influenced by seasonal variation of water masses to some extent.国家自然科学基金项目(41176131); 海洋公益性行业科研经费专项(201305027-8)资

Ecological characters of zooplankton in middle area of Subei Shoal in spring and summer

根据2009年5月和8月在苏北浅滩33°04′--33°12′、121°02′--121°12′水域两个航次浮游动物调查,分析了该水域春夏季浮游动物数量分布、种类组成和优势种特征。结果表明,该区浮游动物优势种季节演替明显,春季(5月)主要优势种为真刺唇角水蚤(lAbIdOCErA EuCHAETA)、小拟哲水蚤(PArACAlAnuS PArVuS)、左突唇角水蚤(l.SInIlObATA)、中华哲水蚤(CAlAnuSSInICuS);夏季(8月)主要优势种为真刺唇角水蚤、百陶箭虫(SAgITTA bEdOTI)、太平洋纺锤水蚤(ACArTIA PACIfICA)。各优势种的季节变化主要受温度影响,呈现夏季暖温种减少、暖水种增多的趋势。春、夏季浮游动物平均生物量分别为1 091.23 Mg/M3和487.11 Mg/M3,平均丰度为1 855.59个/M3和871.37个/M3,春季生物量和丰度都明显高于夏季。苏北浅滩大丰水域春夏季浮游动物数量较高,生物多样性好,群落结构稳定,可为该区各种鱼类及其仔稚幼鱼提供丰富饵料,是鱼类良好的产卵和育幼场所。Based on the zooplankton samples collected from the middle area of Subei Shoal(33°04′～33°12′,121°02′～121°12′) during May & Aug 2009,the ecological characters of zooplankton in the area were studied,such as the quantity,dominant species and season changes.The result showed that the succession of dominant species in the two seasons was obvious.Labidocera euchaeta,Paracalanus parvus,L.sinilobata and Calanus sinicus were the primary dominant species in spring(May).L.euchaeta,Sagitta bedoti,Acartia pacifica were the primary species in summer(Aug.).The seasonal variations of dominant species were mainly determined by the change of temperature.In summer the species were decreased and the warm water species added.The average biomass of zooplankton was 1 091.23 mg/m3 in spring and 487.11 mg/m3 in summer.Moreover,the average abundance of zooplankton was 1 855.59 d/m3 in spring and 871.37 d/m3 in summer.According to the large quantity and high diversity of zooplankton in the studied area,in Subei Shoal,some fishes' spawning and nursing grounds provided the abundant food for the fish larvae and juveniles.国家重点基础研究发展计划(973计划)项目(2010CB428705);国家自然科学基金项目(40776077

Relating the distribution of zooplankton abundance in the coastal waters of central Fujian Province to the seasonal variation of water masses

根据2009—2010年在福建中部近海24°55'—25°13'n、119°11'—119°32'E水域冬、春、夏3个季节的调查资料,探讨了该水域浮游动物总丰度与生物量的平面分布、季节变化及其与台湾海峡水团变化的关系。结果表明,调查水域浮游动物的数量在冬、春之交变化较大,而在春、夏季变化较小。浮游动物冬、春两季的平均丰度分别为8.90个/M3和245.65个/M3,夏季为236.82个/M3。冬、春两季,该水域浮游动物的分布特征相近。其数量在近岸较高,向外侧水域逐渐降低。冬季浮游动物的丰度最高为31.56个/M3,春季最高达到831.67个/M3。中华哲水蚤(CAlAnuS SInICuS)是冬、春季影响总丰度变化最主要的种类。与冬、春季不同,夏季浮游动物的数量在离岸水域较高,丰度最高达1053.13个/M3,而在近岸较低,最低值仅19.17个/M3。汉森莹虾(luCIfEr HAnSEnI)、双生水母(dIPHyES CHAMISSOnIS)是影响总丰度变化最主要的种类。浮游动物在各季的不同分布特征与台湾海峡的季节性水团变化有关。受季风转换影响,从冬季到夏季,海峡内沿岸流势力逐渐减弱,台湾暖流水势力逐渐增强,并影响到沿岸的水文环境。这导致调查水域内浮游动物的优势种类由暖温种向暖水种演替。由于冬、春季的重要优势种类中华哲水蚤与夏季的汉森莹虾、双生水母具有不同的温度适应性,受不同性质水团的影响,在近岸和离岸水域各自呈现出不同的数量高低。从而进一步影响到各季浮游动物总数量的分布。In three oceanographic surveys conducted in the coastal waters of central Fujian Province(24°55′—25°13′ N,119°11′—119°32′ E) in December 2009 and April and August 2010,the abundance,biomass,horizontal distribution,and seasonal variation of zooplankton were investigated,and their relation to the seasonal variation of water masses in the Taiwan Strait was examined.The results showed that the numbers of zooplankton changed between winter and spring,but remained steady between spring and summer.In winter and spring,the zooplankton showed similar patterns of distribution,though the distribution pattern was different in summer.The average number of zooplankton was 8.90 ind./m3 in winter and 245.65 ind./m3 in spring.In these two seasons,the zooplankton were most abundant in nearshore waters and gradually diminished offshore.In summer,the average number of zooplankton was 236.82 ind./m3.The zooplankton abundance in nearshore waters was low,but the zooplankton were abundant in offshore waters.To ascertain which species made the greatest contribution to these distribution patterns,the regression contribution of each dominant species′ abundance was computed.In winter and spring,Calanus sinicus was the species whose distribution determined the distribution of zooplankton abundance.In summer,Lucifer hanseni and Diphyes chamissonis exerted the greatest influence on the distribution of zooplankton abundance.As a warm-temperate species,Calanus sinicus usually prospers in low-temperature waters.By contrast,Lucifer hanseni and Diphyes chamissonis are warm-water species;they are usually abundant in high-temperature waters.The adaptability of these three species to water temperature is an important factor in determining the distribution patterns of zooplankton abundance in each season.However,the most important factor is the seasonal variation of the water masses in the Taiwan Strait.This variation leads to the seasonal alternation of the dominant species.In winter,the west side of the Taiwan Strait is controlled by China′s coastal water,which has a low temperature.The dominant species in the investigated waters in winter were warm-temperate species like Calanus sinicus.In spring,as the northeast monsoon weakens,China′s coastal water wanes and the Taiwan Warm Current becomes stronger.However,the west side of the Taiwan Strait is still controlled by China′s coastal water so warm-temperate species are still dominant.In winter and spring,the offshore water has a relatively high temperature because of the Taiwan Warm Current.Correspondingly,in the offshore water Calanus sinicus had a low abundance.The greatest abundance of Calanus sinicus was in the nearshore water.In summer,the southwest monsoon begins and the Taiwan Warm Current dominates.The major species were mainly warm-water species,such as Lucifer hanseni and Diphyes chamissonis.In summer,the water is heavily stratified,and there is an upwelling of bottom water in the nearshore region of the western side of the strait.As a result,the water temperature in this region was the lowest.Accordingly,warm-water species such as Lucifer hanseni and Diphyes chamissonis,were less abundant in the nearshore water.The different distribution patterns of these important zooplankton species further influenced the total abundance and overall distribution patterns in different seasons.国家重点基础研究发展计划(973计划)项目(2010CB428705);国家自然科学基金项目(40776077

The influence of upwelling and water mass on the ecological group distribution of zooplankton in Zhejiang coastal waters

依据2010年4月、7月和11月对浙江中部近海上升流海域进行的海洋调查资料,运用定量、定性方法,探讨了上升流对该海域浮游动物生态类群分布的影响。结果表明:3个季节共鉴定浮游动物64种,桡足类占主要优势,包括5个生态类群,分别是暖温带近海种、暖温带外海种、亚热带近海种、亚热带外海种和热带大洋种。在种类数组成上,春季以暖温带近海种为主,夏季则是亚热带近海种和亚热带外海种居多,秋季也是亚热带种居多,其中夏季暖温带种种类数要高于春季和秋季,这一现象与同时期东黄海沿海有所不同,主要是由于上升流将一些在海洋底部度夏的暖温种带至海洋表面造成的。此外,3个季节生态类群都是以近海种为主,表明沿岸流是影响这一海域的最主要的水团。在丰度组成上,4月暖温带近海种占总丰度的98.79%,7月暖温带近海种也是组成丰度的重要部分,10月则是亚热带近海种丰度最高。丰度组成所反映的规律与种类数组成规律一致。上升流的存在导致夏季近海暖温带种大量出现,是影响这一海域浮游动物生态类群组成的重要因素;受长江径流和椒江径流的影响,近海种成为主要生态类群,是这一海域浮游动物的一个重要的生态特征。The Zhejiang region experiences coastal upwelling characterized by low temperatures and high salinities throughout the year but particularly during the summer months.The upwelling in this area brings nutrients from the bottom to the surface,providing nutrients for large numbers of breeding plankton.The large quantities of zooplankton are a major food source for many fish and consequently the offshore waters of Zhejiang are productive fishing grounds.Another effect of the upwelling is that temperate warm water species that normally occur in deeper waters and offshore species are taken along with the current resulting in shifts in local zooplankton species composition and changes to the ecological structure and function of this group.This research was based on data from three oceanographic surveys in the offshore waters of the Yushan fishery during April,July and November of 2010.Using quantitative and qualitative methods,the primary aim of this paper was to examine the influence of upwelling on the ecological distribution of zooplankton in this area.A total of 64 species mainly dominated by copepods were identified which were classified into five major ecological groups including coastal temperate warm water species,offshore temperate warm water species,coastal subtropical water species,offshore subtropical water species and oceanic tropical water species.Coastal temperate warm water species were prevalent in spring,coastal subtropical water species and offshore subtropical water species in summer and subtropical species in autumn.The higher abundance of temperate warm water species such as Calanus sinicus,Paracalanus parvus and Sagitta nagae in summer relative to spring and autumn was primarily caused by the upwelling that transported these species from the bottom to the surface.This phenomenon is very different from the hydrodynamic processes that occur in the East and Yellow China Seas.Additionally,coastal species were the dominant zooplankton group,which means that coastal currents have the greatest influence on species composition in these waters.According to the research of Hu Dun-Xin,the main power of the Zhejiang coastal upwelling comes from the upward movement of subsurface water from the Kuroshio current as it follows the continental shelf.The subsurface water of the Kuroshio current runs southeast to northwest and shifts to the east forming an upwelling when it is blocked by the Chen Island Archipelago.With low temperatures and high salinities,the subsurface water of the Kuroshio current carries temperate warm water species and offshore species.As a result,during periods of coastal upwelling temperate warm water species are carried to the surface from the bottom,producing the unusual phenomenon were the number of temperate warm water species in summer is higher than in spring and autumn,contrary to the situation in other areas that have similar climatic conditions.In terms of abundance,coastal temperate warm water species accounted for 98.79% of the zooplankton in April and also a large proportion in July,whereas coastal subtropical water species were the dominant zooplankton group in October.Upwelling leading to the appearance of large numbers of temperate warm water species is a key factor affecting the ecological composition of zooplankton in these waters.The dominance of coastal species that are influenced by Jiao-Jiang runoff was a prime ecological characteristic of zooplankton in this region.国家自然科学基金项目(40776077); 国家重点基础研究发展计划(973计划)项目(2010CB428705

Comparison of zooplankton lists between Coilia mystus food contents and collections from the Yangtze River Estuary & Hangzhou Bay

2009年6月—8月期间在长江口及杭州湾水域收集了1355尾的凤鲚(COIlIA MySTuS)标本,对其胃含物进行分析,同步采集了取样点附近的浮游动物,比较了凤鲚胃含物食谱与该海域浮游动物种类组成的相似性。结果表明:对浮游动物主要种类而言,河口性的长额刺糠虾(ACAnTHOMySIS lOngIrOSTrIS)的相对重要性指数(IrI)为703.25,占相对重要性指数总和百分比(%IrI)为39.65%,远远超过其它种类,包括任何一个桡足类优势种,因而是凤鲚食谱中的最重要的种类。凤鲚摄食的其它主要种类包括:火腿许水蚤(SCHMACkErIA POPlESIA)(IrI=261.04),虫肢歪水蚤(TOrTAnuS VErMICuluS)(IrI=107.53)、真刺唇角水蚤(lAbIdOCErA EuCHAETA)(IrI=27.27)。以上4种浮游动物%IrI合计为61.96%。在被摄食种类中占优势。因而是凤鲚饵料中最重要的优势种。胃含物和海域浮游动物之间的相似度值大致在0.363—0.365之间;而两者桡足类之间的相似度值在0.521—0.575之间。由此推测凤鲚对个体较小的桡足类采用过滤性摄食,对这些种类的选择性较低。而对个体较大的糠虾则是有选择性追逐摄食。The Coilia mystus,estuary migratory and subject to the Family Engraulidae,mainly distributed along the coastal waters,especially in bay and estuary,is a very important small economic fish.One of the main spawning grounds is located from Yangtze River to Hangzhou bay.Stow net with double stake can be used to harvest it in fishing season.Early research about feeding habits of C.mystus,studies on the food of C.mystus(L.),showed that C.mystus mainly feed on Crustacean,of which Copepods first place,Mysids and Decapoda second.Besides,some references about biological characteristics of C.mystus were referred to feeding habits.However,there have been little exclusive studies on its feeding habits,besides the quantitative analysis studies on C.mystus.In order to investigate the diet of C.mystus,1355 specimens were collected from the Yangtze River estuary and Hangzhou bay from June to August,2009.The stomach contents of the specimens were classified as soon as possible after the collection.Multivariate statistical techniques were used to analyze data on stomach contents and zooplankton composition in the sampling waters.In this paper,index of relative importance(IRI) and percentage index of relative importance(%IRI) were used to depict food species or food groups.Dominance and percentage average abundance were used to determine the dominant species and major groups.Similarity index were performed to analyze their food list from the stomach contents and the zooplankton composition list from the sampling waters,which were collected from the same locations during the fish specimens collection.When the major zooplankton species were concerned,the index of relative importance of Acanthomysis longirostris,a brackish estuarine species,is 703.25,which accounted for 39.65% of total IRI of dominant species,much higher than the other species,even the copepod;therefore,it was the most important species in the food list of C.mystus.The other major species in the stomach contents were Schmackeria poplesia,Labidocera euchaeta and Tortanus vermiculus,with the IRI of 261.04,107.53 and 27.27,respectively.Therefore,the four above mentioned species were the dominant diet of the C.mystus,which accounted to 61.96% of total IRI.The similarity value of the stomach contents and the sampling zooplankton was 0.363-0.365,while the similarity value of copepod between the food diet and the sampling zooplankton was 0.521-0.575.Based on above facts,we speculate that C.mystus filters the smaller copepods as food with less selectivity;however,to the larger Mysidacea species,it prefers to pursue them in a much selective way.国家自然科学基金资助(40776047

Summer diet composition and feeding ecology of large yellow croaker(Larimichthys crocea) in Guanjing Yang

2010年6月在福建省官井洋海域收集579尾大黄鱼(lArIMICHTHyS CrOCEA)标本进行胃含物分析,同步采集取样点附近水域浮游动物及张网样品,比较大黄鱼胃含物种类与水域中生物种类组成的相似性。结果表明:大黄鱼食物种类共32种,种类广泛。大黄鱼主要摄食十足类(相对重要性指标百分比%IrI=49.14%)、鱼类(%IrI=20.47%)、磷虾类(%IrI=18.31%)和糠虾类(%IrI=2.34%),具有以游泳动物、浮游动物为主要食物对象的肉食性摄食习性。细螯虾(lEPTOCHElA grACIlIS)(相对重要性指标IrI=976.10,%IrI=35.38%)和中华假磷虾(PSEudEuPHAuSIA SInICA)(IrI=505.27,%IrI=18.31%)为大黄鱼食物组成中最重要的食物种类。海区中,浮游动物以桡足类为主,占所有浮游动物总丰度的45.03%,主要优势种为太平洋纺锤水蚤(ACArTIA PACIfICA,优势度y=0.14)、双刺唇角水蚤(lAbIdOCErA bIPInnATA,y=0.09)和中华哲水蚤(CAlAnuS SInICuS,y=0.06);张网渔获物共鉴定91种,主要为细螯虾、白姑鱼(ArgyrOSOMuS ArgEnTATuS)、大黄鱼(lArIMICHTHyS CrOCEA)蟳、双斑(CHArybdIS bIMACulATA)、三疣梭子蟹(POrTunuSTrITubErCulATuS)、银鲳(PAMPuS ArgEnTEuS)鮻和棱(lIzA CArInATuS)。研究表明,大黄鱼对食物种类具有明显的选择性,主要体现在喜好追逐捕食海区中的小型虾类和仔、稚、幼鱼以及体型相对较大的浮游动物磷虾类和糠虾类。The population of large yellow croaker(Larimichthys crocea) has declined since the 1970s.Despite the decline,little is known about the feeding behavior and diet of this species.Our objective was to document the dietary composition of large yellow croaker.We collected 579 specimens from the sea near Guanjing Yang,Fujian province during June 2010.We documented the stomach contents of each individual and calculated the occurrence frequency(F%),individual number percentage(N%),weight percent(W%),and an index of relative importance(IRI).In addition,we compared diet composition of the zooplankton and nektonic assemblages in the ambient water.We identified 32 species in the diet.The most abundant were decapoda,fish,euphausiacea,mysidacea,amphipoda,crabs,copepoda,and stomatopoda.Decapoda(%IRI=49.14%) and fish(%IRI=20.47%) were the most important prey groups in the diet.Euphausiacea(%IRI=18.31%) and Mysidacea(%IRI=2.34%) constituted the second most important prey groups.Leptochela gracilis(IRI=976.10,%IRI=35.38%) and Pseudeuphausia sinica(IRI=505.27,%IRI=18.31%) were the most important prey species.Our data suggest that the large yellow croaker is carnivorous and feeds primarily on decapods,fish,and macro zooplankton.The trophic level of the wild large yellow croaker is lower than nektonic-animal feeders but higher than planktonic-animal feeders.The dominant species of the zooplankton assemblage was copepoda,primarily Acartia pacifica(Y=0.14),Labidocera bipinnata(Y=0.09),and Calanus sinicus(Y=0.06).The percent mean abundance of Euphausiacea and Mysidacea was 0.83%.Fish,crabs,and decapods were the most abundant nektonic organisms.We hypothesize that the large yellow croaker exhibits selectivity for food,preferring small decapods,fish larvae,euphausiacea,and mysidacea to other groups.国家自然基金项目(40776047);973计划项目(2010CB428705

Study on feeding habit of Coilia mystus in Yangtze River Estuary

2009年6-8月在长江口及杭州湾水域收集到1 355尾凤鲚(COIlIA MySTuS)样品,取其胃含物并对其饵料组成和数量进行分析。结果表明:长江口长兴岛北港水域每尾凤鲚对桡足类摄食数量为0.10~3.31个,长江口九段沙南槽水域每尾为0.06~0.23个,因此可以认为产卵场凤鲚的摄食强度大于洄游中凤鲚的摄食强度。同时发现,每尾体长为100~150 MM的凤鲚摄食糠虾类数量在0.4个左右,而150~190MM体长组糠虾类的数量在0.1个以下。研究表明,个体较大的凤鲚并未对较大个体的糠虾类有更强的摄食趋势。同样,食物中桡足类数量分布与体长组变化也没有明显的关系。在杭州湾,凤鲚的胃含物和栖息水域中都有大量糠虾出现,而在长江口,凤鲚胃含物有零星糠虾出现,其栖息水域的采样中则没有糠虾记录。这说明栖息水域环境中饵料生物组成的差异是凤鲚饵料种类数量不同的重要原因。此外还发现,凤鲚对中华哲水蚤(CAlAnuS SInICuS)(I=0.89)和长额刺糠虾(ACAnTHOMySIS lOngIrOSTrIS)(I=0.86)选择性较强。而凤鲚对火腿许水蚤(SCHMACkErIA POPlESIA)(I=-0.39,y=0.30)等这些栖息水域环境中的优势种类属被动摄食,不具选择性。研究亮点:目前对凤鲚食性的研究只在凤鲚生物学的叙述中提到,没有食性数量的进一步分析。对长江口及其附近水域凤鲚的食物组成及摄食习性进行分析,并将凤鲚的食物组成与栖息水域中的浮游动物种类数量组成进行比较分析。为凤鲚食性的进一步研究以及凤鲚渔业资源的保护、增殖和合理利用提供基础资料。In order to study the diet composition and quantity of Coilia mystus,1 355 stomach samples of C.mystus collected from Yangtze River Estuary and Hangzhou Bay from June to August in 2009 were analyzed in this paper.The feeding amount of Copepoda ranged from 0.10 ind/fish to 3.31 ind/fish in North Channel,Changxing Island,Shanghai,while 0.06-0.23 ind/fish in South Passage,Jiuduansha Wetland,Shanghai,which indicated that the feeding intensity of C.mystus in spawning ground was relatively higher than that during migration.It's detected that the amount of Mysidacea was about 0.40 ind/fish in 100--150 mm size classes,and 0.10 ind/fish in 150-190 mm ones,which demonstrated that there was no obvious tendency of preying bigger Mysidacea by C.mystus in bigger size classes.Besides,the relationship between amount distribution of Copepoda and the size classes of C.mystus was not evident.Mysidacea was found both in stomachs of C.mystus and water samples collected from Hangzhou Bay,while there was a little amount of Mysidacea in C.mystus and none in water samples collected from Yangtze River Estuary.This showed that different composition of diet organism in various waters was the primary reason for the variety of C.mystus feeding components.It's also found that C.mystus showed a preference for Calanus sinicus(I = 0.89) and Acanthomysis longirostris(I = 0.86),while C.mystus had no active selectivity for dominant species in waters,such as Schmackeria poplesia(I =-0.39,Y = 0.30).国家自然科学基金(40776047);973计划(2010CB428705