Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Alien Species ◽  
Environmental Changes ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
Large River ◽  
Gold Rush ◽  
Physical Habitat ◽  
San Joaquin River ◽  
The Status ◽  
Native Fishes

<em>Abstract.</em>—In this paper, we review information regarding the status of the native fishes of the combined Sacramento River and San Joaquin River drainages (hereinafter the “Sacramento–San Joaquin drainage”) and the factors associated with their declines. The Sacramento–San Joaquin drainage is the center of fish evolution in California, giving rise to 17 endemic species of a total native fish fauna of 28 species. Rapid changes in land use and water use beginning with the Gold Rush in the 1850s and continuing to the present have resulted in the extinction, extirpation, and reduction in range and abundance of the native fishes. Multiple factors are associated with the declines of native fishes, including habitat alteration and loss, water storage and diversion, flow alteration, water quality, and invasions of alien species. Although native fishes can be quite tolerant of stressful physical conditions, in some rivers of the drainage the physical habitat has been altered to the extent that it is now more suited for alien species. This interaction of environmental changes and invasions of alien species makes it difficult to predict the benefits of restoration efforts to native fishes. Possible effects of climate change on California’s aquatic habitats add additional complexity to restoration of native fishes. Unless protection and restoration of native fishes is explicitly considered in future water management decisions, declines are likely to continue.

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 ◽  
Keyword(s):  
New Mexico ◽  
North America ◽  
Gulf Of Mexico ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
Rio Grande ◽  
Large River ◽  
Freshwater Species ◽  
The World ◽  
Native Fishes

<em>Abstract.</em>—The Rio Grande is the fourth longest river in North America and the 22nd longest in the world. It begins as a cold headwater stream in Colorado, flows through New Mexico and Texas, where it becomes warm and turbid and finally empties into the Gulf of Mexico. The diversity of native fishes is high in the Rio Grande ranging from freshwater salmonids in its upper reaches to coastal forms in the lower reaches. Historically, about 40 primary freshwater species inhabited the waters of the Rio Grande. Like many rivers throughout North America, the native fish fauna of this river has been irrevocably altered. Species once present are now extinct, others are threatened or endangered, and the majority of the remaining native fishes are declining in both range and numbers. Today, 17 of the 40 primary native freshwater fishes have been either extirpated in part or throughout the Rio Grande drainage. This chapter examines the river, its fauna, and its current plight.

scholarly journals Ecological assessment of a southeastern Brazil reservoir

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Isabela Martins ◽  
Barbara Sanches ◽  
Philip Robert Kaufmann ◽  
Robert M. Hughes ◽  
Gilmar Bastos Santos ◽  
...  
Keyword(s):  
Land Use ◽  
Alien Species ◽  
Littoral Zone ◽  
Environmental Changes ◽  
Fish Assemblages ◽  
Multiple Scales ◽  
Habitat Characteristics ◽  
Southeastern Brazil ◽  
Physical Habitat ◽  
Aquatic Biota

Reservoirs are artificial ecosystems with multiple functions having direct and indirect benefits to humans; however, they also cause ecological changes and influence the composition and structure of aquatic biota. Our objectives were to: (1) assess the environmental condition of Nova Ponte Reservoir, Minas Gerais state, southeastern Brazil; and (2) determine how the aquatic biota respond to disturbances. A total of 40 sites in the littoral zone of the reservoir were sampled to characterize physical and chemical habitat, land use, and benthic macroinvertebrate and fish assemblages. The predominant type of land cover near the reservoir was natural vegetation. A total of 29 fish species and 39 macroinvertebrate taxa were collected, including eight alien species. Most sites had intermediate levels of human disturbance, however, high levels of degradation were associated with high proportions of alien species. Disturbances at multiple scales may alter natural patterns and processes, leading to environmental changes and damaging biological communities. Our results reinforce the importance of assessing reservoir ecological conditions at several scales. The study of land use, littoral zone physical habitat characteristics, water quality, and assemblage structure set the ground for proposing actions to rehabilitate and conserve aquatic ecosystems.

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):  
Fish Species ◽  
Fish Assemblages ◽  
Sewage Treatment ◽  
Fish Fauna ◽  
Large River ◽  
Water Volume ◽  
Mean Width ◽  
Minas Gerais State ◽  
The World ◽  
Annual Discharge

<em>Abstract.</em>—The Rio das Velhas is a tributary of the Rio São Francisco, one of Brazil’s largest rivers. It is the Rio São Francisco’s second most important tributary in water volume (mean annual discharge of 631 m<sup>3</sup>/s), with a drainage area of 27,867 km<sup>2</sup>, length of 761 km, and mean width of 38 m. Like many other rivers around the world, it became heavily polluted in the 1900s. The Rio das Velhas is the most polluted river of Minas Gerais state because the basin contains approximately 4.5 million people. Unlike other Brazilian rivers, its fish fauna was studied from 1850 to 1856. Fifty-five fish species were recorded; 20 of them were first described at that time, when there were previously no more than 40 known species in the entire São Francisco basin. Recent fish collections, approximately 150 years later, indicate 107 fish species, but some may be locally extinct. There are good prospects of rehabilitating this fauna because of the connectivity of the Rio das Velhas with the São Francisco main stem, its well-preserved tributaries, and increased investments in sewage treatment.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Native Species ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
Large River ◽  
Platte River ◽  
Water Diversions ◽  
The North ◽  
As Species ◽  
South Platte ◽  
The City

<em>Abstract.</em>—From its headwaters in the Rocky Mountains, the Platte River drains 230,362 km<sup>2</sup> in Colorado, Wyoming, and Nebraska. The Platte River is formed by the confluence of the North Platte and South Platte near the city of North Platte, Nebraska, and receives additional flow from the Loup and Elkhorn rivers that drain the Sand Hills region of Nebraska. Water diversions for mining and irrigation began in the 1840s in Colorado and Wyoming, and irrigation diversions in Nebraska began in the 1850s. Construction of dams for control of river flows commenced on the North Platte River in Wyoming in 1904. Additional dams and diversions in the North Platte, South Platte, and Platte rivers have extensively modified natural flow patterns and caused interruptions of flows. Pollution, from mining, industrial, municipal, and agricultural sources, and introductions of 24 nonnative species have also taken their toll. Fishes of the basin were little studied before changes in land use, pollution, and introduction of exotic species began. The current fish fauna totals approximately 100 species from 20 families. Native species richness declines westward, but some species find refugia in western headwaters streams. Declines in 26 native species has led to their being listing as species of concern by one or more basin states.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Federal Government ◽  
Fish Assemblages ◽  
Fish Fauna ◽  
Large River ◽  
Biotic Integrity ◽  
Alien Invasive Species ◽  
Early 20Th Century ◽  
Biological Integrity ◽  
North Central ◽  
Northern Branch

<em>Abstract.</em>—The interior Río Nazas basin is located in arid north-central México. It is an interior drainage, subject to dewatering since the early 20th century, and sustains wide fluctuations in runoff. It drains 85,530 km<sup>2</sup> and has a major dam in the middle reaches, producing a highly controlled river, with 100% consumption for agriculture and urban use. Hydrologic gauge reports at Torreón from the Comisión Nacional del Agua indicate a 10-year average runoff of 581.9 million m3 from 1936 to 1945, and only 66.4 million m3 in 1972, the last year of recorded runoff. Its 13 known native fish species are of Rio Grande/Rio Bravo origin. Eleven are endemic to the basin complex (only one absent from the study area), seven species have been listed by the Mexican federal government as threatened or endangered, and three are undescribed. The basin has 13 invasive alien species. An index of biological integrity (IBI), based on historical data, was applied to the current fish assemblage at 10 localities in the lower basin, below El Palmito reservoir. The IBI ranged from 50 to 57 at sites in the northern branch, to 39–61 in the southern branches, and to 0–57 from below their junction to the lower reaches, and averaged 37 or very poor. The overall biotic integrity is very low, especially near reservoirs and in the lower reaches of the river, where human activities consume all available water. The main causes of fish loss from this interesting fish fauna are alien invasive species, habitat disruption, pollution, and dewatering.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Life Histories ◽  
Fish Assemblages ◽  
Early Stage ◽  
Freshwater Fishes ◽  
Large River ◽  
South Florida ◽  
Subtropical Climate ◽  
Kissimmee River ◽  
Native Fishes ◽  
Florida Platform

<em>Abstract.</em>—Recent decades have seen substantial changes in fish assemblages in rivers of peninsular Florida. The most striking change has involved the addition of nonnative fishes, including taxa from Asia, Africa, and Central and South America. I review recent and historical records of fishes occurring in the Kissimmee River basin (7,800 km<sup>2</sup>), a low-gradient drainage with 47 extant native fishes (one possibly the result of an early transplant), at least 7 foreign fishes (most of which are widely established), and a stocked hybrid. Kissimmee assemblages include fewer marine fishes than the nearby Peace and Caloosahatchee rivers, and fewer introduced foreign fishes than south Florida canals. Fish assemblages of the Kissimmee and other subtropical Florida rivers are dynamic, due to new introductions, range expansions of nonnative fishes already present, and periodic declines in nonnative fish populations during occasional harsh winters. The addition, dispersal, and abundance of nonnative fishes in the basin is linked to many factors, including habitat disturbance, a subtropical climate, and the fact that the basin is centrally located in a region where drainage boundaries are blurred and introductions of foreign fishes commonplace. The first appearance of foreign fishes in the basin coincided with the complete channelization of the Kissimmee River in the 1970s. Although not a causal factor, artificial waterways connecting the upper lakes and channelization of the Kissimmee River have facilitated dispersal. With one possible exception, there have been no basinwide losses of native fishes. When assessing change in peninsular Florida waters, extinction or extirpation of fishes appears to be a poor measure of impact. No endemic species are known from peninsular Florida (although some endemic subspecies have been noted). Most native freshwater fishes are themselves descended from recent invaders that reached the peninsula from the main continent. These invasions likely were associated with major fluctuations in sea level since the original mid-Oligocene emergence of the Florida Platform. As opportunistic invaders, most native freshwater fishes in peninsular Florida are resilient, widespread, and common. At this early stage, it is not possible to predict the long-term consequences caused by the introduction of foreign fishes. We know a few details about the unusual trophic roles and other aspects of the life histories of certain nonnatives. Still, the ecological outcome may take decades to unfold.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
Fish Species ◽  
Colorado River ◽  
Fish Assemblages ◽  
Large River ◽  
Management Program ◽  
Federal State ◽  
Physical Habitat ◽  
Management Actions ◽  
Cooperative Agreements ◽  
Warm Springs

<em>Abstract.</em>—The upper Colorado River basin supports a native ichthyofauna of 14 species or subspecies that have been impacted by poor land-use practices, altered flows, physical habitat fragmentation, competition and predation from nonnative fish species, and degraded water quality. Five taxa are federally endangered, including the large-river species, Colorado pikeminnow <em>Ptychocheilus lucius</em>, humpback chub <em>Gila cypha</em>, bonytail <em>G. elegans</em>, razorback sucker <em>Xyrauchen texanus</em>, and a warm-stream subspecies, Kendall Warm Springs dace <em>Rhinichthys osculus thermalis</em>. Two recovery programs, formed through cooperative agreements among federal, state, tribal, and private agencies and stakeholders, coordinate activities in the upper basin that have helped to resolve water resource issues, implement management actions to minimize or remove threats, and conserve endangered species. A cooperative biological management program among state and federal agencies works to protect the Kendall Warm Springs dace. Conservation agreements have also been established for the other native fish species. Continued public and institutional support for these programs is vital to species recovery and to the balance between long-term species conservation and human demands on the Colorado River system.

Historical Changes in Large River Fish Assemblages of the Americas

2005 ◽  
Keyword(s):  
United States ◽  
Colorado River ◽  
Fish Assemblages ◽  
Habitat Degradation ◽  
Fish Fauna ◽  
Physical Habitat ◽  
Introduced Fish ◽  
Regulated Rivers ◽  
The World ◽  
Lower Colorado River

<em>Abstract.</em>—The lower Colorado is among the most regulated rivers in the world. It ranks as the fifth largest river in volume in the coterminous United States, but its flow is fully allocated and no longer reaches the sea. Lower basin reservoirs flood nearly one third of the river channel and store 2 years of annual flow. Diverted water irrigates 1.5 million ha of cropland and provides water for industry and domestic use by 22 million people in the southwestern United States and northern Mexico. The native fish community of the lower Colorado River was among the most unique in the world, and the main stem was home to nine freshwater species, all of which were endemic to the basin. Today, five are extirpated, seven are federally endangered, and three are being reintroduced through stocking. Decline of the native fauna is attributed to predation by nonnative fishes and physical habitat degradation. Nearly 80 alien species have been introduced, and more than 20 now are common. These nonnative species thrived in modified habitats, where they largely eliminated the native kinds. As a result, the lower Colorado River has the dubious distinction of being among the few major rivers of the world with an entirely introduced fish fauna.

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