Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect ...Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect their spatial and seasonal patterns were determined. Totally 35 and 12 fish egg and larvae taxa were identified, respectively. Over the past several decades, the egg and larval species composition has significantly changed in Haizhou Bay and its adjacent waters, most likely corresponding with the alteration of fishery resources, which are strongly affected by anthropogenic activities and climate change. The Bray-Curtis dissimilarity index identified four assemblages: near-shore bay assemblage, middle bay assemblage and two closely related assemblages(near-shore/middle bay assemblage and middle/edge of bay assemblage). The primary species of each assemblage principally reflected the spawning strategies of adult fish. The near-shore bay assemblage generally occurred in near-shore bay, with depths measuring <20 m, and the middle bay assemblage generally occurred in the middle of bay, with depths measuring 20 to 40 m. Spatial and seasonal variations in ichthyoplankton in each assemblage were determined by interactions between biological behavioral traits and oceanographic features, particularly the variation of local conditions within the constraint of a general reproductive strategy. The results of Spearman's rank correlation analysis indicated that both fish egg and larval abundance were positively correlated with depth, which is critical to the oceanographic features in Haizhou Bay.展开更多
Floodplains are important and distinctive ecosystems around the world,and the recruitment of ichthyoplankton from river to floodplain lakes is crucial to maintain this unique ecosystem.However,this process has not bee...Floodplains are important and distinctive ecosystems around the world,and the recruitment of ichthyoplankton from river to floodplain lakes is crucial to maintain this unique ecosystem.However,this process has not been well documented.In this study,ichthyoplankton were sampled to investigate the details of ichthyoplankton recruitment from the Changjiang(Yangtze)River to the Dongting Lake via a floodway channel,the Songzi River,from May to July in 2013 and 2014.During the study period,41 species of eggs and larvae were sampled.Among the samples,16 were river-lake migratory species(RL),representing 23.5%of the species in the Dongting Lake.In 2013,an estimated 130 million eggs and 3180 million larvae drifted through the sampling section,and in 2014,an estimated 1 060 million eggs and 1040 million larvae drifted through the sampling section.The amount of eggs and larvae of RL reached 3 210 million in 2013 and 1 850 million in 2014,respectively.These results demonstrated the importance of ichthyoplankton recruitment from the river to the lake,as species diversity will decrease sharply without this recruitment.Canonical correspondence analysis(CCA)showed that water temperature and water flow are the two most important factors influencing the spawning activities of fish.To maintain the high fish diversity in the Changjiang floodplain,we suggest to irrigate the channel to increase water discharge and increase the transport of ichthyoplankton from the Changjiang mainstream into the Dongting Lake.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(No.201022001201262004)+1 种基金the Public Science and Technology Research Funds Projects of Ocean(No.201305030)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20120132130001)
文摘Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect their spatial and seasonal patterns were determined. Totally 35 and 12 fish egg and larvae taxa were identified, respectively. Over the past several decades, the egg and larval species composition has significantly changed in Haizhou Bay and its adjacent waters, most likely corresponding with the alteration of fishery resources, which are strongly affected by anthropogenic activities and climate change. The Bray-Curtis dissimilarity index identified four assemblages: near-shore bay assemblage, middle bay assemblage and two closely related assemblages(near-shore/middle bay assemblage and middle/edge of bay assemblage). The primary species of each assemblage principally reflected the spawning strategies of adult fish. The near-shore bay assemblage generally occurred in near-shore bay, with depths measuring <20 m, and the middle bay assemblage generally occurred in the middle of bay, with depths measuring 20 to 40 m. Spatial and seasonal variations in ichthyoplankton in each assemblage were determined by interactions between biological behavioral traits and oceanographic features, particularly the variation of local conditions within the constraint of a general reproductive strategy. The results of Spearman's rank correlation analysis indicated that both fish egg and larval abundance were positively correlated with depth, which is critical to the oceanographic features in Haizhou Bay.
基金Supported by the National Key Research and Development Program of China(No.2016YFC0402005)the Three Gorges Project EcoEnvironmental Monitoring System(No.JJ [2017]-011)+1 种基金the National Natural Science Foundation of China(No.NSFC31400359)the China Three Gorges Corporation(No.0704097)
文摘Floodplains are important and distinctive ecosystems around the world,and the recruitment of ichthyoplankton from river to floodplain lakes is crucial to maintain this unique ecosystem.However,this process has not been well documented.In this study,ichthyoplankton were sampled to investigate the details of ichthyoplankton recruitment from the Changjiang(Yangtze)River to the Dongting Lake via a floodway channel,the Songzi River,from May to July in 2013 and 2014.During the study period,41 species of eggs and larvae were sampled.Among the samples,16 were river-lake migratory species(RL),representing 23.5%of the species in the Dongting Lake.In 2013,an estimated 130 million eggs and 3180 million larvae drifted through the sampling section,and in 2014,an estimated 1 060 million eggs and 1040 million larvae drifted through the sampling section.The amount of eggs and larvae of RL reached 3 210 million in 2013 and 1 850 million in 2014,respectively.These results demonstrated the importance of ichthyoplankton recruitment from the river to the lake,as species diversity will decrease sharply without this recruitment.Canonical correspondence analysis(CCA)showed that water temperature and water flow are the two most important factors influencing the spawning activities of fish.To maintain the high fish diversity in the Changjiang floodplain,we suggest to irrigate the channel to increase water discharge and increase the transport of ichthyoplankton from the Changjiang mainstream into the Dongting Lake.
