scholarly journals The Isotope Hydrology of a Large River System Regulated for Hydropower

2014 ◽  
Vol 31 (3) ◽  
pp. 335-349 ◽  
Author(s):  
C. Soulsby ◽  
C. Birkel ◽  
J. Geris ◽  
D. Tetzlaff
Keyword(s):  
River System ◽  
Large River ◽  
Isotope Hydrology

scholarly journals Effects of Weir Construction on Phytoplankton Assemblages and Water Quality in a Large River System

2018 ◽  
Vol 15 (11) ◽  
pp. 2348 ◽  
Author(s):  
Hae-Jin Lee ◽  
Hae-Kyung Park ◽  
Se-Uk Cheon
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
River System ◽  
Large River ◽  
Anthropogenic Factors ◽  
Centric Diatom ◽  
Nakdong River ◽  
Biological Variables ◽  
Physical Chemical ◽  
The Nakdong River

Flow regulation is one of the most common anthropogenic factors affecting rivers worldwide. In Korea, 16 weirs were constructed along four major rivers from 2009 to 2012. This study aimed to elucidate initial changes in physical, chemical, and biological variables after the construction of consecutive weirs on the Nakdong River, a major large river system. Water quality variables and phytoplankton cell densities were investigated at eight representative sites and compared with the data recorded before the weir construction. There were spatial and temporal changes in the hydraulic retention time (HRT), total phosphorus (TP), and chlorophyll a concentrations among the eight weir sections. HRT increased after the weir construction, while TP and chlorophyll a tended to decrease from the middle to lower section of the Nakdong River. Furthermore, differences were observed in the phytoplankton community composition between 2006–2007 and 2013. There was a marginal decrease in the duration of centric diatom (Stephanodiscus hantzschii) blooms after weir construction. However, Microcystis aeruginosa proliferated more extensively during summer and autumn than it did before the weir construction. Our results suggest that changes in hydrological factors, in response to consecutive weir construction, may contribute to greater physical, chemical, and ecological variability.

Catch‐related and genetic outcome of adult northern pike Esox lucius stocking in a large river system

2018 ◽  
Vol 93 (6) ◽  
pp. 1107-1112 ◽  
Author(s):  
Nicolas Guillerault ◽  
Géraldine Loot ◽  
Simon Blanchet ◽  
Frederic Santoul
Keyword(s):  
River System ◽  
Northern Pike ◽  
Esox Lucius ◽  
Large River ◽  
Pike Esox Lucius

Characterization and causes analysis for algae blooms in large river system

2019 ◽  
Vol 51 ◽  
pp. 101707 ◽  
Author(s):  
Bingfen Cheng ◽  
Rui Xia ◽  
Yuan Zhang ◽  
Zhongwen Yang ◽  
Sheng Hu ◽  
...  
Keyword(s):  
River System ◽  
Large River ◽  
Algae Blooms

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Native Species ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
River System ◽  
Endangered Species Act ◽  
Large River ◽  
Main Stem ◽  
Lake Mead ◽  
Virgin River ◽  
Native Fishes

<em>Abstract.</em>—The Virgin–Moapa River system supports nine native fish species or subspecies, of which five are endemic. Woundfin <em>Plagopterus argentissimus </em>and Virgin River chub <em>Gila seminuda </em>are endemic to the main-stem Virgin River, whereas cooler and clearer tributaries are home to the Virgin spinedace <em>Lepidomeda mollispinis</em>. Moapa dace <em>Moapa coriacea </em>and Moapa White River springfish <em>Crenichthys baileyi moapae </em>are found in thermal springs that form the Moapa River, and Moapa speckled dace <em>Rhinichthys osculus moapae </em>is generally found below the springs in cooler waters. The agricultural heritage of the Virgin–Moapa River system resulted in numerous diversions that increased as municipal demands rose in recent years. In the early 1900s, trout were introduced into some of the cooler tributary streams, adversely affecting Virgin spinedace and other native species. The creation of Lake Mead in 1935 inundated the lower 80 km of the Virgin River and the lower 8 km of the Moapa River. Shortly thereafter, nonnative fishes invaded upstream from Lake Mead, and these species have continued to proliferate. Growing communities continue to compete for Virgin River water. These anthropogenic changes have reduced distribution and abundance of the native Virgin–Moapa River system fish fauna. The woundfin, Virgin River chub, and Moapa dace are listed as endangered, and the Virgin spinedace has been proposed for listing. In this paper we document how the abundance of these species has declined since the Endangered Species Act of 1973. Currently, there is no strong main-stem refugium for the Virgin River native fishes, tributary refugia continue to be shortened, and the Moapa River native fishes continue to be jeopardized. Recovery efforts for the listed and other native fishes, especially in the Virgin River, have monitored the declines, but have not implemented recovery actions effective in reversing them.

Mitigating Impacts of Natural Hazards on Fishery Ecosystems

2008 ◽  
Keyword(s):  
United States ◽  
Hurricane Katrina ◽  
River System ◽  
Oxygen Depletion ◽  
Large River ◽  
Fish Kills ◽  
Subsistence Fisheries ◽  
Inland Fisheries ◽  
Stock Assessments ◽  
Fisheries Restoration

<em>Abstract</em>.—Extensive fish kills, primarily from dissolved oxygen depletion, were reported in rivers and associated backwaters throughout southern Mississippi following Hurricane Katrina. Of particular concern were fisheries associated with the Pascagoula River, the last physically unmodified large river system in the contiguous United States. Posthurricane stock assessments were conducted in 2006 to ascertain appropriate fisheries restoration actions for this internationally recognized natural resource. Emphasis focused on fishes that traditionally supported recreational, artisanal, and subsistence fisheries, primarily sunfish (Centrarchidae) and catfish (Ictaluridae). These fisheries were considered some of the more productive inland fisheries in the state prior to the storm.

scholarly journals Assessment of the Impacts of Anthropogenic Activities on a Large River Using Longfin Eel as a Bioindicator

2020 ◽  
Vol 12 (20) ◽  
pp. 8412
Author(s):  
Olivier Champeau ◽  
James M. Ataria ◽  
Grant L. Northcott ◽  
Gen Kume ◽  
Andrew Barrick ◽  
...  
Keyword(s):  
Native Species ◽  
Anthropogenic Activities ◽  
Economic Value ◽  
River System ◽  
Large River ◽  
Chemical Contamination ◽  
Bioindicator Species ◽  
Tissue Samples ◽  
Anthropogenic Stressors ◽  
Residential Land Use

The Matāura River is the sixth largest river system in New Zealand and has long been subject to agricultural, industrial, and residential land use activities. The catchment has economic value and is of great cultural importance for local Māori, who have concerns over potential adverse impacts that anthropogenic stressors exert on the health of the river. There is a dearth of information on the impacts of these stressors towards the health of native species such as the longfin eel Anguilla dieffenbachii. This study assessed the environmental status of the Matāura River using biological and chemical methodologies incorporating A. dieffenbachii as a bioindicator species for exposure to multiple anthropogenic stressors. A range of biomarkers were measured in caged and wild-caught eels (when available) to characterize site-specific responses to anthropogenic stressors. While there was no clear indication of cumulative impacts moving from pristine headwaters to the lower reaches of the Matāura River, biomarkers of xenobiotic metabolization were induced in A. dieffenbachia and there was evidence of chemical contamination in sediment and tissue samples.

Multiple spawning of amphidromous type ayuPlecoglossus altivelisin a large river, Mogami River System

2008 ◽  
Vol 74 (6) ◽  
pp. 1283-1289 ◽  
Author(s):  
Akio SHIMIZU ◽  
Kazuo UCHIDA ◽  
Miho UDAGAWA ◽  
Makoto OHKUBO ◽  
Haruka ITO ◽  
...  
Keyword(s):  
River System ◽  
Large River ◽  
Multiple Spawning ◽  
Amphidromous Type
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