Spatial patterns in estuarine fish faunas in tropical Queensland: a reflection of interaction between long-term physical and biological processes?

1998 ◽  
Vol 49 (1) ◽  
pp. 31 ◽  
Author(s):  
Marcus Sheaves
Keyword(s):  
Fish Assemblages ◽  
Abundant Species ◽  
Common Species ◽  
Estuarine Fish ◽  
Maximum Deviation ◽  
Seawater Salinity ◽  
Spatial Differences ◽  
Upstream Direction ◽  
Catch Rates

Spatial differences in the distribution and abundance of fish faunas of structurally complex habitats in subtidal areas of three tropical estuaries were investigated by using modified Antillean-Z fish traps. The overall species compositions of the three estuaries were similar; however, the distribution and abundance of species differed substantially both within and among estuaries. Although the abundance of most species declined in an upstream direction, the fish assemblages of upstream areas of different estuaries were similar. In contrast, assemblages in seaward regions were quite distinct. Neither temperature nor turbidity were correlated with catch rates of the most abundant species. Although catch rates of some species were significantly correlated with deviation away from normal seawater salinity, in most cases the correlation with maximum deviation in salinity was much stronger. Thus, decreased catches and the absence of some common species from upstream areas may be related to the influence of long-term (months and years) patterns of salinity. Some species were abundant only in one region of a single creek. This may reflect the close proximity of nearby habitats from which recruits may come.

scholarly journals Spatial variation in the structure of fish assemblages in the Vaalbos National Park, South Africa

Koedoe ◽  
1997 ◽  
Vol 40 (1) ◽  
Author(s):  
I.A. Russell
Keyword(s):  
Spatial Variation ◽  
National Park ◽  
Fish Assemblages ◽  
Abundant Species ◽  
Assemblage Structure ◽  
Length Frequency Distribution ◽  
Length Frequency ◽  
Percentage Cover ◽  
Successful Recruitment

Fish assemblages were sampled at nine sites in the lower Vaal River in the Vaalbos National Park and adjacent properties. A total of 1543 fish from 10 species was recorded. Ordination revealed spatial variation in assemblage structure, with the distinction primarily between communities in rapids and deep pools. Flow velocity, depth and percentage cover were important determinants offish assemblage structure. The length frequency distribution of abundant species indicated successful recruitment. Several differences in the species compliment compared to earlier studies were evident, including high abundance of Barbus paludinosus and Austro^lanis sclateri, and the absence of Barbus anoplus. The length-mass relationships of large cyprmids indicated long-term declines in the physical condition of fish.

scholarly journals Ecological analogies between estuarine bottom trawl fish assemblages from Patos Lagoon, Rio Grande do Sul, Brazil and York River, Virginia, USA

2006 ◽  
Vol 23 (1) ◽  
pp. 234-247 ◽  
Author(s):  
João P. Vieira
Keyword(s):  
Fish Assemblages ◽  
Seasonal Pattern ◽  
Rio Grande ◽  
Abundant Species ◽  
Size Class ◽  
Bottom Trawl ◽  
Estuarine Fish ◽  
Rio Grande Do Sul ◽  
York River ◽  
Patos Lagoon

The structure of estuarine fish assemblages at temperate latitudes in Patos Lagoon (32º05'S, 52º04'W), Rio Grande do Sul, Brazil and York River (37º17'N, 76º33'W), Virginia, USA was compared using mid and late 1970's data from bottom trawl collection to investigate whether geographically isolated fish assemblages have similar ecological structure given similar latitudinal positions on the warmtemperate southwestern and northwestern Atlantic regions, respectively. Since estuarine species often exhibit an ontogenetic shift in habitat requirements or preferences we examined Capture per Unity of Effort by size class (CPUE-SC) and split species into "size ecological taxa" (SET) for analysis. The use of CPUE-SC also allowed the abundance of a SET to be computed by summing the mean CPUE of each size class within that SET and use this information to follows SET's temporal and or spatial abundance. A total of 65 and 63 species was collected during a year of bottom trawling in the Patos Lagoon and York River estuaries, respectively. In both localities the strongest modal size class was < 80 mm TL, and several abundant species were smaller than 100 mm TL. The size between 80 and 100 TL effectively separated several species into discrete SET's in both systems. Those SET's could have different ecological preferences, temporal and spatial distributions and so identified as different "ecological taxa". In warm months, when predation by large fish is most likely, the abundance of fish between 80 and 100 mm TL in "bottom trawl" demersal fish assemblages was low in both systems. Only the sea catfishes, in Patos Lagoon, protected by strong dorsal and pectoral spines, and the Hogchoker, in the York River, protected by burrowing in the bottom substrate, peak in abundance at this size class. The seasonal pattern of estuarine use was similar between localities and did not differ from other warm-temperate estuarine fish assemblages.

Spatial variation of East Asian winter monsoon evolution between northern and southern China since the last glacial maximum

2021 ◽  
pp. 1-14
Author(s):  
Qin Li ◽  
Haibin Wu ◽  
Jun Cheng ◽  
Shuya Zhu ◽  
Chunxia Zhang ◽  
...  
Keyword(s):  
East Asian Winter Monsoon ◽  
Southern China ◽  
Ice Sheets ◽  
Northern China ◽  
Winter Monsoon ◽  
Asian Winter Monsoon ◽  
Spatial Differences ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract The East Asian winter monsoon (EAWM) is one of the most dynamic components of the global climate system. Although poorly understood, knowledge of long-term spatial differences in EAWM variability during the glacial–interglacial cycles is important for understanding the dynamic processes of the EAWM. We reconstructed the spatiotemporal characteristics of the EAWM since the last glacial maximum (LGM) using a comparison of proxy records and long-term transient simulations. A loess grain-size record from northern China (a sensitive EAWM proxy) and the sea surface temperature gradient of an EAWM index in sediments of the southern South China Sea were compared. The data–model comparison indicates pronounced spatial differences in EAWM evolution, with a weakened EAWM since the LGM in northern China but a strengthened EAWM from the LGM to the early Holocene, followed by a weakening trend, in southern China. The model results suggest that variations in the EAWM in northern China were driven mainly by changes in atmospheric carbon dioxide (CO2) concentration and Northern Hemisphere ice sheets, whereas orbital insolation and ice sheets were important drivers in southern China. We propose that the relative importance of insolation, ice sheets, and atmospheric CO2 for EAWM evolution varied spatially within East Asia.

scholarly journals Interannual variability of larval fish assemblages associated with water masses in winter in the Taiwan Strait during 2007–2013

2021 ◽  
Author(s):  
Yu-Kai Chen ◽  
Chia-Yi Pan ◽  
Yi-Chen Wang ◽  
Hsiu-Ju Tseng ◽  
Bo-Kun Su ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Larval Fish ◽  
Taiwan Strait ◽  
Assemblage Structure ◽  
Sea Surface ◽  
Coastal Current ◽  
Annual Variations ◽  
Frontal Zones ◽  
The Taiwan Strait

AbstractIn this study, the interannual variations of ichthyoplankton assemblages in the Taiwan Strait (TS) during the winters of 2007–2013 were determined. The cold China Coastal Current (CCC) and Mixed China Coastal Water (MCCW) intruded into the TS and impinged with the warm Kuroshio Branch Current (KBC) with annual variations. Consequently, the ichthyoplankton community in the TS was mainly structured into two assemblages characterized by differing environmental conditions. The composition of the warm KBC assemblage was relatively stable and was characterized by Diaphus B and Bregmaceros spp. By contrast, the cold MCCW assemblage demonstrated considerable variations over the years, with demersal Gobiidae and Scorpaenidae families considered the most representative. In addition, Benthosema pterotum and Trichiurus spp. were common in both KBC and MCCW assemblages. The distribution of the KBC assemblage demonstrated sharp boundaries in the frontal zones, whereas changes in the assemblage structure between the frontal zones were gradual for the MCCW assemblage, particularly when demersal taxa were dominant. Sea surface temperature and salinity were most strongly associated with variability in the assemblage structure during the study period. Thus, this paper provides a better understanding of long-term larval fish dynamics during winter in the TS.

scholarly journals Comparative Analysis of Distribution of Intertidal Fish Assemblages in Different Estuarine Systems on Northern Coast of Brazil

2017 ◽  
Vol 10 (2) ◽  
pp. 26 ◽  
Author(s):  
Milton Goncalves Silva Junior ◽  
Antonio Carlos Leal Castro ◽  
Ulrich Saint-Paul
Keyword(s):  
Comparative Analysis ◽  
Fish Assemblages ◽  
Coastal Region ◽  
Fish Fauna ◽  
Estuarine Fish ◽  
Northern Coast ◽  
Tidal Creeks ◽  
Estuarine Systems ◽  
Using Data ◽  
High Dynamics

The northern coast of Brazil has more than 30 estuaries distributed along 650 km of coastline. These conditions favor the presence of relatively large fish communities in estuarine environments, but published information on the fish fauna in tidal creeks in northern Brazil is only available for some mangrove systems, and comparative studies between fish estuarine communities in different tidal creeks are less common. The choice of the study area was based on the fact that it has been poorly investigated with regard to estuarine fish fauna in comparison in mangrove tidal creeks using the same fishing gear. The objective of the present study was to compare the composition of the relative biomass of taxonomic, functional and ecological guilds of fish assemblages occurring in estuarine systems along the northern coast of Brazil. The study area of the present comparative analysis extended from the southeastern edge of the Marajoara Gulf to the western edge of the Maranhense Gulf. A comparative analysis among different estuarine systems was performed using data from other studies. The abundance of juveniles was greater in the Caeté, Curuçá and Cururuca estuaries than other estuaries. Cluster analysis separated the estuaries into two distinct groups and significant differences between these groups only exist in relation to geographical proximity. The present investigation indicates that the coastal region between the states of Pará and Maranhão is characterized by high dynamics and environmental heterogeneity, particularly with regard to changes in river discharge and tidal fluctuations. The present results underscore the importance of ecological information on ichthyofauna in tropical estuaries in order to include appropriate descriptors in conservation or restoration processes of marine communities and habitats.

scholarly journals The contribution of environmental factors to fish assemblages in the Río Acahuapa, a small drainage in Central America

2017 ◽  
Vol 15 (3) ◽  
Author(s):  
Francisco S. Álvarez ◽  
Wilfredo A. Matamoros ◽  
Francisco A. Chicas
Keyword(s):  
Fish Species ◽  
Habitat Structure ◽  
Fish Assemblages ◽  
Species Abundance ◽  
Main Channel ◽  
Estuarine Fish ◽  
Species Origin ◽  
High Temperature Water ◽  
Distribution Of Fish ◽  
Temperature Water

ABSTRACT The ichthyofauna of the Río Acahuapa was analyzed sampling 17 sites that included the basin main channel and its tributaries. Fish were collected using dip-nets, seine-nets and electrofishing. Fish standard length and species abundance were recorded. Species origin and salinity tolerance criteria were used to classify fish species. Water physicochemical variables, habitat structure and sampling sites elevation were recorded. A total of 33 fish species were registered, 12.1% are primary, 45.5% are secondary and 42.4% are of marine derivation. Fish species richness declined with increase of elevation (R2=0.55, p=0.0006). Two assemblages of fishes were identified: the first one associated to sites of low elevations (19-184 masl), composed mainly of secondary and marine-estuarine fish species related with high temperature, water velocity, river width, dissolved oxygen and low sand and silt substrate cover; the second one associated to sites of middle and higher elevations (185-519 masl), composed by primary and secondary freshwater fishes related with high pH, logs and rocks substrate cover. In summary, elevation and environmental variables contributed to the composition and distribution of fish in the Río Acahuapa.

scholarly journals Long-Term Trends in Small Mammals on a Right-of-Way in Pennsylvania, U.S.

2007 ◽  
Vol 33 (2) ◽  
pp. 147-152
Author(s):  
Richard Yahner ◽  
Richard Yahner ◽  
Russell Hutnik
Keyword(s):  
Small Mammals ◽  
Forest Cover ◽  
Common Species ◽  
The State ◽  
Mammal Species ◽  
Right Of Way ◽  
Live Trapping ◽  
Long Term Trends

The State Game Lands 33 Research and Demonstration Area, Centre County, Pennsylvania, U.S., has been studied since 1953 with the objective of comparing the effectiveness of commonly used mechanical and herbicidal maintenance treatments on vegetation and wildlife on a right-of-way (ROW). Small mammals are important wildlife species on a ROW by consuming tree seeds, thereby reducing invasion of undesirable tree species, and these mammals are important components of a healthy ecosystem. As a follow up to a 2-year study of small mammals conducted 15 years earlier (1989 to 1990) on the State Game Lands 33 ROW, we initiated a 2-year live-trapping study in 2004 on small mammal populations on this ROW. The objectives of our study were to determine relative abundance and species richness (number of species) in six major cover types and in the adjacent forest. One hundred twenty-one individuals of eight species were observed in 2004 and 2005 combined; the most common species was the white-footed mouse (Peromyscus leucopus). One of the most important cover types to small mammals on the ROW was forb-grass, whereas the forest cover type tended to be less diverse in terms of number of mammal species than in cover types on the ROW.

Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

2017 ◽  
Keyword(s):  
Size Structure ◽  
Population Decline ◽  
Round Goby ◽  
Management Plan ◽  
Neogobius Melanostomus ◽  
Before And After ◽  
Catch Rates ◽  
Survival Studies ◽  
St Lawrence River

<em>Abstract</em>.— Long-term research indicates a significant and ongoing decline within the upper St. Lawrence River Muskellunge <em>Esox masquinongy </em>population. Index surveys show a sharp reduction in catch of both spawning adults and age-0 Muskellunge, and catch rates by anglers have similarly declined while harvest remains low. Other changes associated with population decline include presence of fewer female adult Muskellunge and a change in adult Muskellunge size structure (increase in proportion of fish <1,016 mm) in addition to more large individuals greater than 1,372 mm. A significant adult die-off occurred from 2005 to 2008 (103 adults recovered in U.S. and Canadian waters) concomitant with an outbreak of viral hemorrhagic septicemia (VHS). These population changes were also temporally correlated with detection and proliferation of invasive Round Goby <em>Neogobius melanostomus</em>, a known VHS virus (VHSV) reservoir, egg predator, and competitor with native fishes. Comparisons of index netting before and after VHSV and Round Goby invasions suggest a direct link to the decline, but because these are correlations, we can only explore these effects. To examine the viability of Muskellunge nursery sites, we repeated survival studies conducted in the early 1990s with experimental releases of advanced fry at four locations during 2013–2015. Findings indicate contribution to age-0 populations, but catches poststocking (wild and stocked) were lower compared to the 1990s. We review information regarding potential stressors, including VHSV and Round Goby invasion, and conclude that their combined effects have created significant uncertainty and challenges to sustainable management of the Muskellunge population. In response, the St. Lawrence River Muskellunge management plan should be updated with a focus on restoration of the declining Muskellunge stock. Recommended actions target advancing conservation and restoration of critical habitat, restoring lost subpopulations, and reducing mortality associated with angling (e.g., from handling and harvest).

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