scholarly journals Seasonal variations of the ichthyoplankton assemblage in the Yangtze Estuary and its relationship with environmental factors

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6482 ◽  
Author(s):  
Hui Zhang ◽  
Weiwei Xian ◽  
Shude Liu
Keyword(s):  
Seasonal Variations ◽  
Historical Data ◽  
Wiener Index ◽  
Abundant Species ◽  
Diversity Indices ◽  
Yangtze Estuary ◽  
The Yangtze Estuary ◽  
Factors Affecting ◽  
Annual Variations ◽  
Major Factors

Seasonal variations of the ichthyoplankton assemblage and its relationship with the environment were analyzed based on four seasonal surveys during 2012. Historical data was collected to be compared with results from previous years in order to indicate the seasonal and inter-annual variation of the ichthyoplankton assemblage in the Yangtze Estuary and the adjacent waters. A total of 3,688 individuals belonging to 5 orders, 9 families, and 15 species were collected. No samples were collected in the winter cruise. In 2012, all samples were separated into four ecotypes, which is comparable with the historical data from previous years. The Engraulis japonicus was the most abundant species of all teleost fishes. The E. japonicus was captured in every season and contributed the most to the abundance of ichthyoplankton, which was greater than that of previous years. This result may be due to the periodic fluctuations of E. japonicus or from the displacement of spawning grounds offshore for environmental reasons. The diversity indices of the assemblage were significantly different among seasons, with the number and abundance of the species peaking in the spring, while richness, evenness and diversity indices peaked in the autumn. The species richness of the ichthyoplankton varied from 0.74 to 1.62, the Pielou evenness index varied from 0.10 to 0.49 and the Shannon–Wiener index varied from 0.19 to 1.04. The results of CCA analysis showed that the major factors affecting the ichthyoplankton assemblage differed throughout the seasons. Chla was the key factor affecting the ichthyoplankton in 2012. These seasonal and inter-annual variations likely resulted from migrations associated with fish spawning as well as the environment. Compared with data from previous studies, the relationship between the assemblage structure of ichthyoplankton and corresponding environmental variables have undergone a decline.

scholarly journals Spring Ichthyoplankton Assemblage Structure in the Yangtze Estuary Under Environmental Factors

2021 ◽  
Vol 8 ◽  
Author(s):  
Yibang Wang ◽  
Cui Liang ◽  
Zhaomin Chen ◽  
Shude Liu ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Dominant Species ◽  
Large Scale ◽  
Yangtze Estuary ◽  
Assemblage Structure ◽  
The Yangtze Estuary ◽  
Larimichthys Polyactis ◽  
Factors Affecting ◽  
Coilia Mystus ◽  
Trachidermus Fasciatus ◽  
Fish Spawning

Estuaries, where fresh and salty water converge, provide abundant nutrients for ichthyoplankton. Ichthyoplankton, including fish eggs, larvae, and juveniles, are important fishery recruitment resources. The Yangtze Estuary and its adjacent waters comprise a typical large-scale estuary and supply many important fish spawning, feeding, and breeding areas. In this study, 1,291 ichthyoplankton individuals were collected in the Yangtze Estuary in spring, from 2013 to 2020. The aims of the study were to provide detailed information on characteristics of the ichthyoplankton assemblage, explore interannual variation, and evaluate the effects of environmental variables on the temporal variation in assemblage structure. Twenty-six species in seventeen families were identified. The dominant species were Coilia mystus, Chelidonichthys spinosus, Engraulis japonicus, Hypoatherina valenciennei, Larimichthys polyactis, Salanx ariakensis, Stolephorus commersonnii, and Trachidermus fasciatus. The ichthyoplankton assemblage changed significantly over time, and Chelidonichthys spinosus became one of the dominant species. Canonical correspondence analysis showed that temperature and chlorophyll a were the key factors affecting the assemblage structure in the Yangtze Estuary in spring.

scholarly journals Diversity of Earthworms in Nnamdi Azikiwe University, Awka

2019 ◽  
Vol 4 (2) ◽  
pp. 39-45
Author(s):  
C.O. Okoye ◽  
C.O. Chiejina ◽  
C.C. Ezeorah ◽  
J.J. Okeke ◽  
C.D. Ezeonyejiaku ◽  
...  
Keyword(s):  
Soil Moisture Content ◽  
Species Abundance ◽  
Abundant Species ◽  
Diversity Indices ◽  
Factors Affecting ◽  
Average Value ◽  
Enhanced Production ◽  
Sampling Locations ◽  
Diverse Habitat ◽  
Earthworm Populations

AbstractStudies reveal that not up to 50% of earthworm species have been described in the world and the understanding of earthworm diversity is finite in most countries including Nigeria. The study was aimed at evaluating the diversity of earthworms and environmental factors affecting their abundance. Earthworms were collected from three (3) different sampling locations in Nnamdi Azikiwe University, Awka. Descriptive statistics and estimation of species abundance, dominance and diversity were used to analyze the data obtained from the study. From the study, four (4) species of earthworms were identified and recorded from the three sampling locations. Eudrilus eugeniae (54.9%) was the most abundant species followed by Hyperidrilus africanus (20.3%), Libyodrilus violaceous (19.6%) and Alma millsoni (6.3%) with the least abundant species. The result of the diversity indices showed Science village (1.13) as the most diverse habitat followed by Emelda hostel (0.86) and Boys’ hostel (0.84) with the least diversity of species. Soil pH ranged from 2.25 to 4.06 and total organic matter ranged from 14.10 to 16.36%. Soil temperature was uniform with an average value of 27°C for the three sampling locations. The soil moisture content ranged from 11.19 to 14.12%. The conductivity recorded the lowest value (25.60μS/cm) in Emelda Hostel and highest value (111.8 μS/cm) in Science village. The study provided understanding into the patterns of earthworm populations in Nnamdi Azikiwe University, Awka and the need for the conservation of earthworm diversity. Better understanding about habitat and living conditions of earthworms is required to provide suitable and enhanced production of vermicompost in different geographic conditions.

scholarly journals Autumn ichthyoplankton assemblage in the Yangtze Estuary shaped by environmental factors

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1922 ◽  
Author(s):  
Hui Zhang ◽  
Weiwei Xian ◽  
Shude Liu
Keyword(s):  
Environmental Factors ◽  
Correspondence Analysis ◽  
Canonical Correspondence Analysis ◽  
Environmental Changes ◽  
Yangtze Estuary ◽  
Environmental Data ◽  
The Yangtze Estuary ◽  
Annual Variations ◽  
Trichiurus Lepturus ◽  
Seawater Salinity

This study investigated the response of the ichthyoplankton community to environmental changes in the Yangtze Estuary using canonical correspondence analysis. Ichthyoplankton community and environmental data were recorded during the autumns of 1998, 2000, 2002, 2003, 2004, 2007 and 2009. Among the ichthyoplankton, the dominant larval and juvenile families were the Engraulidae, Gobiidae and Salangidae, and the most common eggs were fromTrichiurus lepturus. The ichthyoplankton was identified via canonical correspondence analysis to three assemblages: an estuary assemblage dominated byChaeturichthys stigmatias, a coastal assemblage dominated byEngraulis japonicusandStolephorus commersonii, and an offshore assemblage dominated byTrichiurus lepturus. Regarding environmental factors in the Yangtze Estuary, suspended matter and surface seawater salinity were the main factors influencing the distributions of the different assemblages, while sediment from the Yangtze River during the rainy season and chlorophyllawere the principle drivers of the annual variances in the distribution of ichthyoplankton assemblages. Our aims in this study were to provide detailed characterizations of the ichthyoplankton assemblage in the autumns of seven years, examine the long-term dynamics of autumn ichthyoplankton assemblages, and evaluate the influence of environmental factors on the spatial distribution and inter-annual variations of ichthyoplankton assemblages associated with the Yangtze Estuary.

Spatial and Seasonal Variations of Heavy Metals in Wetland Soils of the Tidal Flats in the Yangtze Estuary, China: Environmental Implications

Pedosphere ◽  
2013 ◽  
Vol 23 (4) ◽  
pp. 511-522 ◽  
Author(s):  
Xue-Feng HU ◽  
Yan DU ◽  
Jian-Wei FENG ◽  
Sheng-Qiong FANG ◽  
Xiao-Jiang GAO ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seasonal Variations ◽  
Yangtze Estuary ◽  
Tidal Flats ◽  
Wetland Soils ◽  
Environmental Implications ◽  
The Yangtze Estuary

Occurrence, impact variables and potential risk of PPCPs and pesticides in a drinking water reservoir and related drinking water treatment plants in the Yangtze Estuary

2018 ◽  
Vol 20 (7) ◽  
pp. 1030-1045 ◽  
Author(s):  
Cong Xu ◽  
Lei Chen ◽  
Luhua You ◽  
Zheng Xu ◽  
Long-Fei Ren ◽  
...  
Keyword(s):  
Drinking Water ◽  
Potential Risk ◽  
Temporal Change ◽  
Water Reservoir ◽  
Drinking Water Treatment ◽  
Yangtze Estuary ◽  
The Yangtze Estuary ◽  
Factors Affecting ◽  
Drinking Water Reservoir ◽  
The World

PPCPs and pesticides have been documented throughout the world over the years, yet relatively little is known about the factors affecting their spatial distribution and temporal change in order to know their potential risk to the ecosystem or human health in the future.

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