Influence of environmental variables on the fish fauna of the deeper waters of a large Australian estuary

1987 ◽  
Vol 94 (4) ◽  
pp. 631-641 ◽  
Author(s):  
N. R. Loneragan ◽  
I. C. Potter ◽  
R. C. J. Lenanton ◽  
N. Caputi
Keyword(s):  
Environmental Variables ◽  
Fish Fauna ◽  
Australian Estuary

scholarly journals Fish complementarity is associated to forests in Amazonian streams

2015 ◽  
Vol 13 (3) ◽  
pp. 579-590 ◽  
Author(s):  
Carolina Rodrigues Bordignon ◽  
Lilian Casatti ◽  
María Angélica Pérez-Mayorga ◽  
Fabrício Barreto Teresa ◽  
Gabriel Lourenço Brejão
Keyword(s):  
Habitat Use ◽  
Functional Traits ◽  
Fish Species ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
Functional Structure ◽  
Structure Of Communities ◽  
Net Relatedness Index ◽  
Functional Homogenization

The functional structure of communities is commonly measured by the variability in functional traits, which may demonstrate complementarity or redundancy patterns. In this study, we tested the influence of environmental variables on the functional structure of fish assemblages in Amazonian streams within a deforestation gradient. We calculated six ecomorphological traits related to habitat use from each fish species, and used them to calculate the net relatedness index (NRI) and the nearest taxon index (NTI). The set of species that used the habitat differently (complementary or overdispersed assemblages) occurred in sites with a greater proportion of forests. The set of species that used the habitat in a similar way (redundant or clustered assemblages) occurred in sites with a greater proportion of grasses in the stream banks. Therefore, the deforestation of entire watersheds, which has occurred in many Amazonian regions, may be a central factor for the functional homogenization of fish fauna.

scholarly journals Do environmental variables predict the trophic structure of fish fauna in a subtropical river (Uruguay River Ecoregion)?

2018 ◽  
Vol 77 (2) ◽  
Author(s):  
Mayara P. Neves ◽  
Dirceu Baumgartner ◽  
Gilmar Baumgartner ◽  
Rosilene L. Delariva
Keyword(s):  
Environmental Variables ◽  
Trophic Structure ◽  
Fish Fauna ◽  
Environmental Parameters ◽  
Inorganic Phosphorus ◽  
Trophic Guilds ◽  
River Continuum ◽  
Environmental Filters ◽  
Energy Flows ◽  
Numerical Abundance

Trophic interactions represent the routes through which energy flows upwards within ecosystems and the understanding of such structuring under varying environmental conditions is still challenging. Here we test the hypothesis that differences in environmental variables act as environmental filters on the composition and trophic structure of local the fish fauna of a subtropical mountain river. We predict that differences in the trophic structure of the fish fauna occur along the river continuum. Main environmental parameters have been measured and fishes were sampled quarterly between August 2013 and May 2014 at six sampling sites in the main channel of the Pelotas River, Upper Uruguay ecoregion. We collected 3848 individuals belonging to 38 species, 4 orders and 11 families. The most (82.1%) consisted of small- and medium-sized individuals. The species were classified into eight trophic guilds: aquatic insectivorous, carnivorous, detritivorous, detritivorous/aquatic insectivorous, herbivorous, iliophagous, omnivorous and piscivorous. In general, herbivorous and piscivorous guilds were the most representative in both number and biomass. Significant differences detected by Permanova were for richness, numerical abundance and biomass between all the sites sampled. Relationships between the environmental variables and the composition of trophic guilds were observed along the longitudinal gradient by RLQ and fourth-corner analyses. The abundance of guilds omnivorous, aquatic insectivorous and herbivorous increases with higher values of chlorophyll-a and vegetation cover, especially characterizing the upstream sites (S1, S2 and S3). On the other hand, the abundance of the iliophagous, detritivorous/insectivorous and piscivorous guilds increases with greater values of width, temperature, inorganic phosphorus and total solids, a fact observed in downstream sites (S4, S5 and S6). Thus, it was possible to identify a clear variation in the trophic structure of the fish fauna along the Pelotas River (upstream-downstream), in which the local variables were efficient in predicting environmental filters that influence the trophic organization. In this scenario, our study follows the longitudinal model and evidences a greater accumulation of energy in food webs in the upstream-downstream direction, which favors the greatest abundance of piscivorous, detritivorous and iliophagous verified in stretches of greater volume and dimensions of river. These results highlight the importance of the local variables and the interrelationships in the lateral connectivity processes along the river continuum.

Spatial and seasonal differences in the fish fauna in the shallows of a large Australian estuary

1986 ◽  
Vol 92 (4) ◽  
pp. 575-586 ◽  
Author(s):  
N. R. Loneragan ◽  
I. C. Potter ◽  
R. C. J. Lenanton ◽  
N. Caputi
Keyword(s):  
Fish Fauna ◽  
Seasonal Differences ◽  
Australian Estuary

scholarly journals Environmental Variables and Ecological Distribution of Ichthyofauna Assemblages in the Calabar River, Nigeria: Present and Future Prospects

2016 ◽  
Vol 74 (4) ◽  
pp. 159-171
Author(s):  
Andem Bassey Andem ◽  
Sunday Ben Ekanem ◽  
Esien Ene Oku
Keyword(s):  
Surface Water ◽  
Water Temperature ◽  
Environmental Variables ◽  
Fish Fauna ◽  
Dry Season ◽  
Fish Diversity ◽  
Surface Water Temperature ◽  
Future Prospects ◽  
Ecological Distribution ◽  
Wet Season

Abstract Studies on environmental variables and ecological distribution of ichthyofauna assemblages were conducted in the Calabar River. Surface water and ichthyofauna were sampled in order to provide baseline or reference data on the Calabar River at present as regard its future prospects. Seasonal variation shows significant differences in surface water temperature, pH, DO, BOD, conductivity, TDS and TSS between sampling stations and insignificant differences in heavy metals such as cadmium, chromium, iron and copper between sampling stations. Twenty six species of fish fauna were identified belonging to twenty two families. Mugilidae, Clariidae, Cichlidae, Gobiidae and Sciaenidae were the most abundant for both wet and dry season, while Clupeidae, Bathyclupeidae, Carangidae and Sphyraenidae were low in the wet season but high in the dry season. Chromium, copper, surface water temperature, DO correlate significantly with the presence of E. fimbriata, B. soporator, M. sebae, C. gariepinus, M. loennbergii, C. guentheri and P. babarus. The overall values of biotic diversity indices ranged from 0.0504-0.0745 for Simpson’s Index, 2.770-3.095 for Shannon Index, 2.821-3.105 for Margalef’s Index and 0.8606-0.9498 for equitability. However, the presence of certain fish fauna in polluted and non-polluted parts of the river indicates that they could be used as potential bioindicators in assessment and biomonitoring of the river. The methods used in identifying fish diversity proved their applicability for future studies.

The fish fauna of a seasonally closed Australian estuary. Is the prevalence of estuarine-spawning species high?

1993 ◽  
Vol 116 (1) ◽  
pp. 19-30 ◽  
Author(s):  
I. C. Potter ◽  
G. A. Hyndes ◽  
F. M. Baronie
Keyword(s):  
Fish Fauna ◽  
Australian Estuary

Seasonal and spatial changes in the larval fish fauna within a large temperate Australian estuary

1992 ◽  
Vol 112 (1) ◽  
pp. 1-16 ◽  
Author(s):  
F. J. Neira ◽  
I. C. Potter ◽  
J. S. Bradley
Keyword(s):  
Larval Fish ◽  
Fish Fauna ◽  
Spatial Changes ◽  
Australian Estuary
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