The Effects of Improved Water Quality on Fish Assemblages in a Heavily Modified Large River System

2015 ◽  
Vol 32 (5) ◽  
pp. 992-1007 ◽  
Author(s):  
J. Parker ◽  
J. Epifanio ◽  
A. Casper ◽  
Y. Cao
Keyword(s):  
Water Quality ◽  
Fish Assemblages ◽  
River System ◽  
Large River

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.

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.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Author(s):  
Keyword(s):  
Water Quality ◽  
Waste Treatment ◽  
Fish Assemblages ◽  
Large River ◽  
Low Flow ◽  
Physical Habitat ◽  
Willamette River ◽  
Habitat Alterations ◽  
The Past ◽  
Species Occurrences

<em>Abstract.</em>—The Willamette River is Oregon’s largest river, with a basin area of 29,800 km<sup>2</sup> and a mean annual discharge of 680 m<sup>3</sup>/s. Beginning in the 1890s, the channel was greatly simplified for navigation. By the 1940s, it was polluted by organic wastes, which resulted in low dissolved oxygen concentrations and floating and benthic sludge deposits that hindered salmon migration and boating. Following basin-wide secondary waste treatment and low-flow augmentation, water quality markedly improved, salmon runs returned, and recreational uses increased. However, water pollution remains a problem as do physical habitat alterations, flow modification, and alien species. Fish assemblages in the main-stem Willamette River were sampled systematically, but with different gear, in the summers of 1945, 1983, and 1999. In the past 53 years, tolerant species occurrences decreased and intolerant species occurrences increased. In the past 20 years, alien fishes have expanded their ranges in the river, and four native fish species have been listed as threatened or endangered. We associate these changes with improved water quality between 1945 and 1983, fish migrations, altered flow regimes and physical habitat structure, and more extensive sampling.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Waste Treatment ◽  
Fish Assemblages ◽  
River System ◽  
Agricultural Runoff ◽  
Large River ◽  
Smallmouth Bass ◽  
Ohio River ◽  
Micropterus Dolomieu ◽  
Wabash River ◽  
Spotted Bass

<em>Abstract.</em>—The present ichthyofauna (1965–2001) of the Wabash River system is compared to that of three periods: presettlement through 1820, 1875–1900, and 1940– 1950. This second largest Ohio River tributary flows freely for 350 mi. However, its environment and watershed have been altered greatly from presettlement times; twothirds has been converted to agriculture, eliminating all prairies and most forests and wetlands. Canals, large and small dams, channelization, and effluents have extinguished 12 fish species, diminished some, and favored others. Thirteen of approximately 175 species are recent, including 3 aliens. Better municipal and industrial waste treatment has improved water quality, but excessive agricultural runoff remains detrimental to many fishes. Degraded habitats exacerbate these problems. Many sensitive species are today either absent or severely reduced in distribution and abundance compared to 50 years ago. Smallmouth bass <em>Micropterus dolomieu </em>has been replaced by largemouth bass <em>M. salmoides </em>or spotted bass <em>M. punctulatus, </em>and few visual piscivores occur except near reservoirs.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Water Quality ◽  
Land Management ◽  
Native Species ◽  
Fish Assemblages ◽  
Large River ◽  
Nonnative Species ◽  
Quarter Century ◽  
Aggressive Management ◽  
Major Factors ◽  
River Fish

<em>Abstract.</em>—Fish assemblages in the Verde River, Arizona have changed markedly over the last quarter century. Nonnative fishes increase from headwaters toward the mouth and individual native species decrease. River hydrograph and the introduction of nonnative species appear to be the major factors determining fish assemblages, although information is lacking on water quality and other land management impacts. During floods, native species dominated fish assemblages. By contrast, during droughts and sustained base flows, nonnative fishes increased. The threatened spikedace <em>Meda fulgida </em>has been collected only in the uppermost reach of this desert river and, even here, has been absent since 1997. Five other native species also have become less abundant or rare. Continued monitoring of fish assemblages, comparison with another large southwestern river, the Gila, and aggressive management are critical to sustain the native fish component of this river.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Endemic Species ◽  
Fish Assemblages ◽  
Habitat Degradation ◽  
Fish Fauna ◽  
River System ◽  
Large River ◽  
Past Century ◽  
Species Dispersal ◽  
Geologic History ◽  
Additional Species

<em>Abstract.</em>—The Alabama River system, comprising the Alabama, Coosa, and Tallapoosa subsystems, forms the eastern portion of the Mobile River drainage. Physiographic diversity and geologic history have fostered development in the Alabama River system of globally significant levels of aquatic faunal diversity and endemism. At least 184 fishes are native to the system, including at least 33 endemic species. During the past century, dam construction for hydropower generation and navigation resulted in 16 reservoirs that inundate 44% of the length of the Alabama River system main stems. This extensive physical and hydrologic alteration has affected the fish fauna in three major ways. Diadromous and migratory species have declined precipitously. Fish assemblages persisting downstream from large main-stem dams have been simplified by loss of species unable to cope with altered flow and water quality regimes. Fish populations persisting in the headwaters and in tributaries to the mainstem reservoirs are now isolated and subjected to effects of physical and chemical habitat degradation. Ten fishes in the Alabama River system (including seven endemic species) are federally listed as threatened or endangered. Regional experts consider at least 28 additional species to be vulnerable, threatened, or endangered with extinction. Conserving the Alabama River system fish fauna will require innovative dam management, protection of streams from effects of urbanization and water supply development, and control of alien species dispersal. Failure to manage aggressively for integrity of remaining unimpounded portions of the Alabama River system will result in reduced quality of natural resources for future generations, continued assemblage simplification, and species extinctions.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Fish Assemblage ◽  
Yellow Perch ◽  
Fish Assemblages ◽  
Poor Performance ◽  
River System ◽  
Fish Passage ◽  
Large River ◽  
Critical Threshold ◽  
Upstream Migration ◽  
Micropterus Dolomieu

<em>Abstract.</em>—The Saint John River is located on the mainland of eastern North America, forming in northern Maine–southeastern Quebec, and flows east and south through New Brunswick. Fish collections were conducted at sites located from 135 to 625 km above the mouth in 2000 and 2001. Methods development trials demonstrated that the highest success was achieved with a standardized netting protocol consisting of a combination of dusk seining, nighttime electrofishing, and short-term gill net sets. A total of 36 species of fish were collected, with the greatest diversity occurring at the farthest downstream site. Upstream migration of anadromous species is restricted by the absence or poor performance of fish passage facilities at the five hydroelectric dams along the river system. The downstream migration of introduced muskellunge <em>Esox masquinongy </em>and upstream range expansions of introduced smallmouth bass <em>Micropterus dolomieu </em>and rainbow trout <em>Oncorhynchus mykiss </em>were observed. Fish species and abundances varied along the river, but the cumulative effects of human activities were not easily identified within the fish assemblage. There may have been a critical threshold within the fish assemblage defined by an accumulation of 20 anthropogenic developments. Cyprinid species declined in abundance and yellow perch <em>Perca flavescens </em>and brown bullhead <em>Ameiurus nebulosus </em>increased in abundance downstream of this apparent threshold.

Water Quality Aspects of the Nakdong Estuary Barrage

1984 ◽  
Vol 16 (1-2) ◽  
pp. 243-252 ◽  
Author(s):  
J W van Sluis ◽  
L Lijklema
Keyword(s):  
Water Quality ◽  
Water Quality Management ◽  
Sewage Treatment ◽  
Large River ◽  
Model Verification ◽  
Nakdong River ◽  
Treated Effluent ◽  
Quality Aspects ◽  
The Nakdong River ◽  
Few Data

As a result of the construction of a barrage in the estuary of the Nakdong river the size of the estuary will be considerably reduced. In addition, a large river reservoir is created upstream of the barrage. Main points of interest are the effects of the discharge of raw sewage and treated effluent into the Nakdong river on the water quality in the projected reservoir and the water quality forecasts for the remaining part of the estuary, in relation with the existing plans for sewerage and sewage treatment for the city of Busan. In addition, measures to reduce the effects of the barrage and the outline of a water quality management programme are presented. Special consideration is given to the methodological aspects of the water quality study, i.e. the selection and use of mathematical models in a situation where input data are rather uncertain and only very few data for parameter estimation and model verification are available.

Sign in / Sign up

Export Citation Format

Share Document