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At least 37 records · Page 2Linked to original sources
USGS2005

Status and conservation of the fish fauna of the Alabama River system

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. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Effects of landscape change on fish assemblage structure in a rapidly growing metropolitan area in North Carolina, USA

We evaluated a comprehensive set of natural and land-use attributes that represent the major facets of urban development at fish monitoring sites in the rapidly growing Raleigh-Durham, North Carolina metropolitan area. We used principal component and correlation analysis to obtain a nonredundant subset of variables that extracted most variation in the complete set. With this subset of variables, we assessed the effect of urban growth on fish assemblage structure. We evaluated variation in fish assemblage structure with nonmetric multidimensional scaling (NMDS). We used correlation analysis to identify the most important environmental and landscape variables associated with significant NMDS axes. The second NMDS axis is related to many indices of land-use/land-cover change and habitat. Significant correlations with proportion of largest forest patch to total patch size (r = -0.460, P < 0.01), diversity of patch types (r = 0.554, P < 0.001), and population density (r = 0.385, P < 0.05) helped identify NMDS axis 2 as a disturbance gradient. Positive and negative correlations between the abundance of redbreast sunfish Lepomis auritus and bluehead chub Nocomis leptocephalus, respectively, and NMDS axis 2 also were evident. The North Carolina index of biotic integrity and many of its component metrics were highly correlated with urbanization. These results indicate that aquatic ecosystem integrity would be optimized by a comprehensive integrated management strategy that includes the preservation of landscape function by maximizing the conservation of contiguous tracts of forested lands and vegetative cover in watersheds. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Changes in the fish fauna of the Kissimmee River basin, peninsular Florida: Nonnative additions

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 km2), 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 basin-wide 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.

American Fisheries Society Symposium↗
USGS2005

Aquatic assemblages of the highly urbanized Santa Ana River Basin, California

We assessed the structure of periphyton, benthic macroinvertebrate, and fish assemblages and their associations with environmental variables at 17 sites on streams of the highly urbanized Santa Ana River basin in Southern California. All assemblages exhibited strong differences between highly urbanized sites in the valley and the least-impacted sites at the transition between the valley and undeveloped mountains. Results within the urbanized area differed among taxa. Periphyton assemblages were dominated by diatoms (>75% of total taxa). Periphyton assemblages within the urbanized area were not associated with any of the measured environmental variables, suggesting that structure of urban periphyton assemblages might be highly dependent on colonization dynamics. The number of Ephemeroptera, Trichoptera, and Plecoptera (EPT) taxa included in macroinvertebrate assemblages ranged from 0 to 6 at urbanized sites. Benthic macroinvertebrate assemblages had significant correlations with several environmental variables within the urban area, suggesting that stream size and permanence were important determinants of distribution among the species able to survive conditions in urban streams. Only 4 of 16 fish species collected were native to the drainage. Fish assemblages of urbanized sites included two native species, arroyo chub Gila orcuttii and Santa Ana sucker Catostomus santaanae, at sites that were intermediate in coefficient of variation of bank-full width, depth, bed substrate, and water temperature. Alien species dominated urbanized sites with lesser or greater values for these variables. These results suggest that urban streams can be structured to enhance populations of native fishes. Continued study of urban streams in the Santa Ana River basin and elsewhere will contribute to the basic understanding of ecological principles and help preserve the maximum ecological value of streams in highly urbanized areas.

American Fisheries Society Symposium↗
USGS2005

A legacy of change: The lower Colorado River, Arizona-California-Nevada, USA, and Sonora-Baja California Norte, Mexico

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. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Uncertainty and research needs for supplementing wild populations of anadromous Pacific salmon

Substantial disagreement and uncertainty attend the question of whether the benefits from supplementing wild populations of anadromous salmonids with hatchery fish outweigh the risks. Prudent decisions about supplementation are most likely when the suite of potential benefits and hazards and the various sources of uncertainty are explicitly identified. Models help by indicating the potential consequences of various levels of supplementation but perhaps are most valuable for showing the limitations of available data and helping design studies and monitoring to provide critical data. Information and understanding about the issue are deficient. I discuss various benefits, hazards, and associated uncertainties for supplementation, and implications for the design of monitoring and research. Several studies to reduce uncertainty and facilitate prudent supplementation are described and range from short-term reductionistic studies that help define the issue or help avoid deleterious consequences from supplementation to long-term studies (ca. 10 or more fish generations) that evaluate the net result of positive and negative genetic, behavioral, and ecological effects from supplementation.

American Fisheries Society Symposium↗
USGS2005

Genetic diversity, kinship analysis, and broodstock management of captive Atlantic sturgeon for population restoration

Captive Atlantic sturgeon Acipenser oxyrinchus considered for use as broodstock in a restoration program were genotyped using nuclear DNA microsatellites and compared to wild collections from the Hudson River, New York (source of parents of the captive sturgeon) and from Albemarle Sound, North Carolina. Because the potential broodfish were the progeny of a small number of parents, maintaining genetic diversity and minimizing inbreeding is essential to a successful breeding and supplementation program. The microsatellite loci used in this analysis generated unique multilocus genotypes for each of 136 Atlantic sturgeon. Analyses indicated significant genetic separation between the New York and North Carolina collections and correctly identified the potential broodstock as a subset of the Hudson River population. Pairwise genetic distance (-In proportion of shared alleles) between half and full siblings in the potential broodfish was as great as 1.386, a value exceeded by only 36% of the sampled broodfish pairs available for mating. Because the current broodstock population does not seem to have deviated far from their ancestral population in the Hudson River, progeny from that broodstock, or the parents themselves, would seem to be genetically suitable for release back into the Hudson River.

American Fisheries Society Symposium↗
USGS2005

Diet overlap of introduced rainbow trout and three native fishes in an Ozark stream

Private angling groups in Oklahoma have requested permission to stock rainbow trout Oncorhynchus mykiss into streams of northeastern Oklahoma although little is known regarding interactions between introduced rainbow trout and native fishes in these systems. Our study objectives were to assess diet overlap between introduced rainbow trout and native smallmouth bass Micropterus dolomieu, shadow bass Ambloplites ariommus, and bluegill sunfish Lepomis macrochirus in Brush Creek, Oklahoma, a small spring-fed Ozark stream. Rainbow trout diet composition differed from that of all three native fishes in the 2 months of comparison (March and May 2001), and rainbow trout diets contained relatively low numbers of prey. It is unlikely that exploitative competition for food resources occurred between rainbow trout and these three native fishes. ?? 2004 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Use of an urban intensity index to assess urban effects on streams in three contrasting environmental settings

To assess the effects of urbanization on assemblages (fish, invertebrate, and algal), physical habitat, and water chemistry, we investigated the relations among varying intensities of basin urbanization and stream ecology in three metropolitan areas: the humid northeastern United States around Boston, Massachusetts; the humid southeastern United States around Birmingham, Alabama; and the semiarid western United States around Salt Lake City, Utah. A consistent process was used to develop a multimetric urban intensity index (UII) based on locally important variables (land-use/land-cover, infrastructure, and socioeconomic variables) in each study area and a common urban intensity index (CUII) based on a subset of five variables common to all study areas. The UII was used to characterize 30 basins along an urban gradient in each metropolitan area. Study basins were located within a single ecoregion in each of the metropolitan areas. The UII, ecoregions, and site characteristics provided a method for limiting the variability of natural landscape characteristics while assessing the magnitude of urban effects. Conditions in Salt Lake City (semiarid climate and water diversions) and Birmingham (topography) required nesting sites within the same basin. The UII and CUII facilitated comparisons of aquatic assemblages response to urbanization across different environmental settings. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Hydrologic changes in urban streams and their ecological significance

Urban development modifies the production and delivery of runoff to streams and the resulting rate, volume, and timing of streamflow. Given that streamflow demonstrably influences the structure and composition of lotic communities, we have identified four hydrologic changes resulting from urban development that are potentially significant to stream ecosystems: increased frequency of high flows, redistribution of water from base flow to storm flow, increased daily variation in streamflow, and reduction in low flow. Previous investigations of streamflow patterns and biological assemblages provide a scale of ecological significance for each type of streamflow pattern. The scales establish the magnitude of changes in streamflow patterns that could be expected to produce biological responses in streams. Long-term streamflow records from eight streams in urbanizing areas of the United States and five additional reference streams, where land use has been relatively stable, were analyzed to assess if streamflow patterns were modified by urban development to an extent that a biological response could be expected and whether climate patterns could account for equivalent hydrologic variation in the reference streams. Changes in each type of streamflow pattern were evident in some but not all of the urban streams and were nearly absent in the reference streams. Given these results, hydrologic changes are likely significant to urban stream ecosystems, but the significance depends on the stream's physiographic context and spatial and temporal patterns of urban development. In urban streams with substantially altered hydrology, short-term goals for urban stream rehabilitation may be limited because of the difficulty and expense of restoring hydrologic processes in an urban landscape. The ecological benefits of improving physical habitat and water quality may be tempered by persistent effects of altered streamflow. In the end, the hydrologic effects of urban development must be addressed for restoration of urban streams. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2009

Critical uncertainties and research needs for the restoration and conservation of native lampreys in North America

We briefly reviewed the literature, queried selected researchers, and drew upon our own experience to describe some critical uncertainties and research needs for the conservation and restoration of native lampreys in North America. We parsed the uncertainties and research needs into five general categories: (1) population status; (2) systematics; (3) passage at dams, screens, and other structures; (4) species identification in the field; and (5) geneal biology and ecology. For each topic, we describe why the subject is important for lampreys, briefly smmarize our current state of knowledge, and discuss the key data or information gaps.

American Fisheries Society Symposium↗
USGS2011

An evaluation of agreement between pectoral spines and otoliths for estimating ages of catfishes

Otoliths have been shown to provide more accurate ages than pectoral spine sections for several catfish populations; but sampling otoliths requires euthanizing the specimen, whereas spines can be sampled non-lethally. To evaluate whether, and under what conditions, spines provide the same or similar age estimates as otoliths, we examined data sets of individual fish aged from pectoral spines and otoliths for six blue catfish Ictalurus furcatus populations (n=420), 14 channel catfish Ictalurus punctatus populations (n=997), and 10 flathead catfish Pylodictus olivaris populations (n=947) from lotic and lentic waters throughout the central and eastern U.S. Logistic regression determined that agreement between ages estimated from otoliths and spines was consistently related to age, but inconsistently related to growth rate. When modeled at mean growth rate, we found at least 80% probability of no difference in spine- and otolith-assigned ages up to ages 4 and 5 for blue and channel catfish, respectively. For flathead catfish, an 80% probability of agreement between spine- and otolith-assigned ages did not occur at any age due to high incidence of differences in assigned ages even for age-1 fish. Logistic regression models predicted at least 80% probability that spine and otolith ages differed by &le;1 year up to ages 13, 16, and 9 for blue, channel, and flathead catfish, respectively. Age-bias assessment found mean spine-assigned age differed by less than 1 year from otolith-assigned age up to ages 19, 9, and 17 for blue catfish, channel catfish, and flathead catfish, respectively. These results can be used to help guide decisions about which structure is most appropriate for estimating catfish ages for particular populations and management objectives.

American Fisheries Society Symposium↗
USGS2013

Interactions between striped bass and other gamefish in reservoirs

Competitive interactions among reservoir fishes may be pronounced because fish assemblages in these artificial environments have had little time to develop niche-partitioning strategies that alleviate negative interspecific interactions. Such interactions may at times have been intensified by introductions of predators such as striped bass Morone saxatilis , introduced to create additional fisheries and control pelagic clupeids. Possible interactions between existing fish assemblages and striped bass include predation and competition. While there is a perception among angler groups that predation by striped bass on co-existing game fish is significant, most studies have reported little or no predation on game fish my striped bass and have considered predation rare and inconsequential. Moreover, predation that occurs will likely be compensatory and fail to reduce overall game fish survival. Any indirect effect of striped bass predation by restricting prey-sized game fish to limited refuge sites remains unknown. Exploitative competition may be more common. Although infrequently, introduced striped bass have depleted prey resources shared with other piscivores, particularly when stocking rates have been high, when there is a high rate of natural reproduction, or when prey supply has plunged in response to environmental fluxes. Fluctuation in prey supply, associated with ordinary environmental variability, and associated time lages in prey supply and predator demand, preclude adjusting predator densities to exactly balance demand with supply. The frequency of low supply-demand rations varies across systems and exhibits seasonal trends. Nevertheless, chronic supply-demand imbalances are manageable where the predator assemblage is at least partially controlled through stocking, harvest regulations, or both. Because of the poor state of knowledge concerning the parameters defining balance and because uncontrollable annual fluctuations preclude exact management of alternating prey levels, we suggest adjusting stocking to manage demand to that it equals the median historical prey supply. Simulating the removal of striped bass and predicting the aftermath may be the most cost-efficient way to provide decision support for stakeholders involved in determining if a striped bass stocking program is beneficial to most users.

American Fisheries Society Symposium↗
USGS2015

Spotted bass Micropterus punctulatus (Rafinesque 1819)

Three subspecies of Spotted Bass Micropterus punctulatus were historically recognized: the smaller Northern Spotted Bass M. p. punctulatus , the larger, longer-lived Alabama Spotted Bass M. p. henshalli , and the now invalidated Wichita Spotted Bass M. p. wichitae (Bailey and Hubbs 1940; Cofer 1995; Warren 2009; Rider and Maceina 2015, this volume). The subspecific status has been examined over the past decade as advanced genetic analyses have been developed (e.g., Kassler et al. 2002; Baker et al. 2008; Tringali et al. 2015, this volume). The American Fisheries Society has recently changed the designation of the Alabama Spotted Bass to a separate species, Alabama Bass M. henshalli (Page et al. 2013). The remainder of this paper will discuss the biology and conservation of only Spotted Bass. Both species have been observed to hybridize with other Micropterus spp. (Koppelman 1994; Pierce and Van Den Avyle 1997; Barwick et al. 2006).

American Fisheries Society Symposium↗
USGS2011

Ictalurids in Iowa’s streams and rivers: Status, distribution, and relationships with biotic integrity

Anthropogenic alterations to Iowa’s landscape have greatly altered lotic systems with consequent effects on the biodiversity of freshwater fauna. Ictalurids are a diverse group of fishes and play an important ecological role in aquatic ecosystems. However, little is known about their distribution and status in lotic systems throughout Iowa. The purpose of this study was to describe the distribution of ictalurids in Iowa and examine their relationship with ecological integrity of streams and rivers. Historical data (i.e., 1884–2002) compiled for the Iowa Aquatic Gap Analysis Project (IAGAP) were used to detect declines in the distribution of ictalurids in Iowa streams and rivers at stream segment and watershed scales. Eight variables characterizing ictalurid assemblages were used to evaluate relationships with index of biotic integrity (IBI) ratings. Comparisons of recent and historic data from the IAGAP database indicated that 9 of Iowa’s 10 ictalurid species experienced distribution declines at one or more spatial scales. Analysis of variance indicated that ictalurid assemblages differed among samples with different IBI ratings. Specifically, total ictalurid, sensitive ictalurid, and Noturus spp. richness increased as IBI ratings increased. Results indicate declining ictalurid species distributions and biotic integrity are related, and management strategies aimed to improve habitat and increase biotic integrity will benefit ictalurid species.

American Fisheries Society Symposium↗