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.

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):  
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):  
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.

Reconciling Environmental and Flood Control Goals on an Arid-Zone River: Case Study of the Limitrophe Region of the Lower Colorado River in the United States and Mexico

2008 ◽  
Vol 41 (3) ◽  
pp. 322-335 ◽  
Author(s):  
Edward P. Glenn ◽  
Kate Hucklebridge ◽  
Osvel Hinojosa-Huerta ◽  
Pamela L. Nagler ◽  
Jennifer Pitt
Keyword(s):  
United States ◽  
Flood Control ◽  
Colorado River ◽  
Arid Zone ◽  
The United States ◽  
Lower Colorado River

scholarly journals Supplemental Material: Redefining the age of the lower Colorado River, southwestern United States

2021 ◽  
Author(s):  
Ryan Crow ◽  
et al.
Keyword(s):  
United States ◽  
Colorado River ◽  
Southwestern United States ◽  
Analytical Results ◽  
Lower Colorado River

Additional details on methods, summary of previous Ar/Ar dating relevant to the timing of Colorado River integration, sample locations, and full analytical results.<br>

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.

scholarly journals Processed 1938 aerial photography for selected areas of the lower Colorado River, southwestern United States

2006 ◽  
Author(s):  
Laura M. Norman ◽  
Michael Gishey ◽  
Leila Gass ◽  
Brian Yanites ◽  
Edwin Pfeifer ◽  
...  
Keyword(s):  
United States ◽  
Aerial Photography ◽  
Colorado River ◽  
Southwestern United States ◽  
Lower Colorado River

scholarly journals Supplemental Material: Redefining the age of the lower Colorado River, southwestern United States

2021 ◽  
Author(s):  
Ryan Crow ◽  
et al.
Keyword(s):  
United States ◽  
Colorado River ◽  
Southwestern United States ◽  
Analytical Results ◽  
Lower Colorado River

Additional details on methods, summary of previous Ar/Ar dating relevant to the timing of Colorado River integration, sample locations, and full analytical results.<br>

scholarly journals Metrics derived from fish assemblages as indicators of environmental degradation in Cerrado streams

2018 ◽  
Vol 35 ◽  
pp. 1-8
Author(s):  
Milton P. Ávila ◽  
Rafaela Neves Carvalho ◽  
Lilian Casatti ◽  
Juliana Simião-Ferreira ◽  
Lorrane Faria de Morais ◽  
...  
Keyword(s):  
Environmental Degradation ◽  
Fish Assemblages ◽  
Habitat Degradation ◽  
Conservation Status ◽  
Stream Fish ◽  
Physical Habitat ◽  
Dominance Index ◽  
Environmental Characteristics ◽  
Monitoring Tools ◽  
Stream Fish Assemblages

The development of effective monitoring tools depends on finding sensitive metrics that are capable of detecting the most important environmental impacts at a given region. We assessed if metrics derived from stream fish assemblages reflect physical habitat degradation and changes in land cover. We sampled the ichthyofauna and environmental characteristics of 16 stream sites of first and second order in the Upper Tocantins River basin. The streams were classified according to their environmental characteristics into reference (n = 5), intermediate (n = 4), and impacted (n = 7). A total of 4,079 individuals in five orders, 12 families, and 30 species were collected. Of the 20 metrics tested, eight were non-collinear and were tested for their performance in discriminating among groups of streams. Three metrics were sensitive to the gradient of degradation: Berger-Parker dominance index, percentage of characiform fish, and percentage of rheophilic individuals. Some commonly used metrics did not reflect the disturbances and many others were redundant with those that did. These results indicate that the metrics derived from fish assemblages may be informative for identifying the conservation status of streams, with the potential to be used in biomonitoring.

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