Environmental Changes, Habitat Modifications and Feeding Ecology of Freshwater Fish

2008 ◽  
pp. 35-65 ◽  
Author(s):  
Norma Hahn ◽  
Rosemara Fugi
Keyword(s):  
Freshwater Fish ◽  
Feeding Ecology ◽  
Environmental Changes

scholarly journals A review of length-weight relationships of freshwater fishes in Malaysia

2018 ◽  
Vol 20 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Amonodin Mohamad Radhi ◽  
Mohd-Fadzil Nurul Fazlinda ◽  
Mohammad Noor Azmai Amal ◽  
Hashim Rohasliney
Keyword(s):  
Freshwater Fish ◽  
Fish Species ◽  
Environmental Changes ◽  
Meta Analysis ◽  
Freshwater Fishes ◽  
Clarias Batrachus ◽  
Ecological Health ◽  
Allometric Growth ◽  
Freshwater Fish Species

Abstract This manuscript reviews the length-weight relationships (LWRs) of freshwater fishes in Malaysia. A total of 102 LWRs of fishes gathered from literature pertaining to 64 freshwater fish species were analysed. A meta-analysis from 13 previous reports showed that the b values was ranged from 2.19 (Clarias batrachus) to 4.106 (Barbodes binotatus). Out of 64 observed species, 47 species (11 families) experienced positive allometric growth, while another 23 species (eight families) and 31 species (12 families) were recorded under isometric and negative allometric growth, respectively. The fish LWRs observed can be used as an indicator of environmental changes and fish ecological health for freshwater fishes in Malaysia.

scholarly journals Broad and fine-scale threats on threatened Brazilian freshwater fish: variability across hydrographic regions and taxonomic groups

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Murilo Luiz e Castro Santana ◽  
Fernando Rogério Carvalho ◽  
Fabrício Barreto Teresa
Keyword(s):  
Freshwater Fish ◽  
Habitat Loss ◽  
Fish Species ◽  
Threatened Species ◽  
Environmental Changes ◽  
Anthropogenic Impacts ◽  
Conservation Status ◽  
Fine Scale ◽  
Hydrographic Regions ◽  
Taxonomic Groups

Abstract: Anthropogenic environmental changes are the main cause of species extinction during the Holocene. Species have been exposed to major source of threats, such as habitat loss and fragmentation, pollution, introduced species, and harvesting, many of which are derived from specific anthropogenic activities, such as urbanization, agriculture, and damming (i.e. fine-scale threats). However, the importance of these threats on the species conservation status in a given region depends on the type of impacts they are exposed to and the susceptibility of species to these impacts. In this study, we used a database of threatened Brazilian freshwater fish species to test whether the major source of threats and the specific anthropogenic impacts to species vary across hydrographic regions and taxonomic groups. Our results showed that habitat loss is a ubiquitous major threat jeopardizing the conservation status of the Brazilian fish species. However, different fine-scale threats mediate this process across hydrographic regions and taxonomic groups. The combination of impacts from agriculture, deforestation, and urbanization affects most of the threatened species in the basins of the Northeast, South, and Southeast, including the species of the most threatened order, the Cyprinodontiformes. Damming is the main human activity affecting threatened species of Siluriformes, Characiformes, Gymnotiformes, and Cichliformes, especially in northern basins (Amazon and Tocantins-Araguaia). Therefore, we found that specific fine-scale threats influencing threatened species vary across hydrographic regions and taxonomic groups, probably due to geographic variability in the incidence of human activities and differential niche requirements and vulnerability of species to these activities.

scholarly journals Distribution, abundance, and feeding ecology of baleen whales in Icelandic waters: have recent environmental changes had an effect?

2015 ◽  
Vol 3 ◽  
Author(s):  
Gísli A. Víkingsson ◽  
Daniel G. Pike ◽  
Héðinn Valdimarsson ◽  
Anna Schleimer ◽  
Thorvaldur Gunnlaugsson ◽  
...  
Keyword(s):  
Feeding Ecology ◽  
Environmental Changes ◽  
Baleen Whales ◽  
Icelandic Waters

scholarly journals Feeding ecology of Hypostomus punctatus Valenciennes, 1840 (Osteichthyes, Loricariidae) in a costal stream from Southeast Brazil

2010 ◽  
Vol 70 (3) ◽  
pp. 569-574 ◽  
Author(s):  
R. Mazzoni ◽  
CF. Rezende ◽  
LR. Manna
Keyword(s):  
Feeding Ecology ◽  
Environmental Conditions ◽  
Rainy Season ◽  
Environmental Changes ◽  
Feeding Habit ◽  
Frequency Of Occurrence ◽  
Feeding Preferences ◽  
Food Items ◽  
Southeast Brazil ◽  
Dry Seasons

In the present study we aimed to compare the feeding ecology of Hypostomus punctatus from a coastal stream from Southeast Brazil with data previously published for the same study site before environmental changes. Feeding preferences were assessed through a sample of 138 specimens (67 from the dry and 71 from the rainy season) using the Index of Alimentary Importance (IAi). We registered five different food items (detritus, plant fragments, Diatoms, Chloroficeae and Cianobacteries) composing the species diet. Detritus was the most abundant one both during the rainy and dry seasons (IAirainny = 90.34 and IAidry = 96.30). No significant differences were registered for the volume of food items consumed during the rainy and dry seasons. The Frequency of Occurrence analysis showed that four (detritus, plant fragments, Diatoms and Chloroficeae) among the five all other consumed ones, were always frequent. Comparing our own results with those available for the study site, we suggest that the feeding habit of H. punctatus has changed according to environmental changes and that the species diet is strongly dependent upon environmental conditions.

scholarly journals Feeding ecology of Pachyurus bonariensis Steindachner, 1879 (Sciaenidae: Perciformes) in the Ibicuí River, Southern Brazil: ontogenetic, seasonal and spatial variations

2010 ◽  
Vol 70 (3) ◽  
pp. 503-509 ◽  
Author(s):  
DO. Lima ◽  
ER. Behr
Keyword(s):  
Feeding Ecology ◽  
Environmental Changes ◽  
Spatial Variations ◽  
Plant Matter ◽  
Seasonal And Spatial Variations ◽  
Biological Characters ◽  
Dietary Variation ◽  
Lotic Environments ◽  
Sciaenid Fish ◽  
Diptera Larvae

Knowledge of the feeding ecology of fish is essential for understanding the functioning of freshwater communities. Here we report on an analysis of the diet of Pachyurus bonariensis Steindachner, 1879, a freshwater sciaenid. Fish were collected bimonthly from December 1999 to January 2002 at three locations along the Ibicuí River in the Rio Grande do Sul State, Brazil. At each location, the specimens were collected in both lentic and lotic environments. The stomachs of 324 fish were analysed for contents and fullness. The main items were Ephemeroptera, Diptera (larvae), Trichoptera and Odonata. Annelida, plant matter, Decapoda, Diptera (pupae), Coleoptera and Mollusca were present in small amounts. The fish consumed smaller amounts of food in winter than in other seasons. The most important source of dietary variation for P. bonariensis was the ontogenetic, related to intrinsic biological characters. However, spatial variation was also found, suggesting that this species can adapt its diet to environmental changes. Although P. bonariensis showed ontogenetic and spatial variations in the main items consumed, the main items were always insects, characterising P. bonariensis as a fish with an insectivorous feeding habit in the Ibicuí River.

Feeding ecology of the freshwater fish rohuLabeo rohita(Hamilton 1822): a case of intelligent feeding in the periphyton-based environment

2013 ◽  
Vol 23 (4) ◽  
pp. 266-274 ◽  
Author(s):  
Surjya Kumar Saikia ◽  
Sandip Majumder ◽  
Sudarshana Nandi ◽  
Samar Kumar Saha
Keyword(s):  
Freshwater Fish ◽  
Feeding Ecology

scholarly journals Contribution of conservation genetics in assessing neotropical freshwater fish biodiversity

2008 ◽  
Vol 68 (4 suppl) ◽  
pp. 1039-1050 ◽  
Author(s):  
NM. Piorski ◽  
A. Sanches ◽  
LF. Carvalho-Costa ◽  
T. Hatanaka ◽  
M. Carrillo-Avila ◽  
...  
Keyword(s):  
Conservation Genetics ◽  
Freshwater Fish ◽  
Environmental Changes ◽  
Fish Fauna ◽  
Fish Populations ◽  
Food Sources ◽  
Isolated Populations ◽  
Long Distance ◽  
Fish Biodiversity ◽  
Population Structuring

Human activities have a considerable impact on hydrographic systems and fish fauna. The present review on conservation genetics of neotropical freshwater fish reveals that DNA analyses have been promoting increased knowledge on the genetic structure of fish species and their response to environmental changes. This knowledge is fundamental to the management of wild fish populations and the establishment of Evolutionary Significant Units capable of conserving genetic integrity. While population structuring can occur even in long-distance migratory fish, isolated populations can show reduced genetic variation and be at greater risk of extinction. Phylogeography and phylogeny have been powerful tools in understanding the evolution of fish populations, species and communities in distinct neotropic environments. Captive fish can be used to introduce new individuals and genes into the wild and their benefits and disadvantages can be monitored through genetic analysis. Understanding how fish biodiversity in neotropical freshwaters is generated and maintained is highly important, as these habitats are transformed by human development and fish communities are increasingly exploited as food sources to sustain a growing human population.

Linking transcription, RNA polymerase II elongation and alternative splicing

2020 ◽  
Vol 477 (16) ◽  
pp. 3091-3104 ◽  
Author(s):  
Luciana E. Giono ◽  
Alberto R. Kornblihtt
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Rna Polymerase Ii ◽  
Environmental Changes ◽  
Transcription Elongation ◽  
Single Gene ◽  
Regulation Of Gene Expression ◽  
Regulation Of Transcription ◽  
Stepping Stones ◽  
Eukaryotic Transcription

Gene expression is an intricately regulated process that is at the basis of cell differentiation, the maintenance of cell identity and the cellular responses to environmental changes. Alternative splicing, the process by which multiple functionally distinct transcripts are generated from a single gene, is one of the main mechanisms that contribute to expand the coding capacity of genomes and help explain the level of complexity achieved by higher organisms. Eukaryotic transcription is subject to multiple layers of regulation both intrinsic — such as promoter structure — and dynamic, allowing the cell to respond to internal and external signals. Similarly, alternative splicing choices are affected by all of these aspects, mainly through the regulation of transcription elongation, making it a regulatory knob on a par with the regulation of gene expression levels. This review aims to recapitulate some of the history and stepping-stones that led to the paradigms held today about transcription and splicing regulation, with major focus on transcription elongation and its effect on alternative splicing.

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