Geology topics

David L. Galat

Publications and source records attributed to David L. Galat.

8 recordsLinked to original sources

USGS2015

Sensitivity of shovelnose sturgeon ( Scaphirhynchus platorynchus ) and pallid sturgeon ( S. albus ) early life stages to 3,30,4,40,5-pentachlorobiphenyl and 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure

Concern exists that polychlorinated biphenyls (PCBs) may be contributing to the current decline of shovelnose sturgeon ( Scaphirhynchus platorynchus ) and the US federally endangered pallid sturgeon ( Scaphirhynchus albus ). Waterborne exposures with newly fertilized eggs were used to assess developmental and morphological effects of 2 of the most potent aryl hydrocarbon receptor (AhR) agonists, 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126) and 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD), on early life stage shovelnose and pallid sturgeon. No dose-related effects of PCB-126 were observed on percent development or hatch in either species at concentrations as high as 1711 ng/g egg. Effects of TCDD on percent development were not assessed in shovelnose sturgeon. However, percent development was not affected by TCDD in pallid sturgeon, and percent hatch was unaffected by TCDD doses as high as 60 ng/g egg to 81 ng/g egg in either species. Morphological pathologies such as yolk sac edema and craniofacial deformities were typical of AhR agonist exposure and were similar in both species. Calculated PCB-126 50% lethal dose (LD50, 95% fiducial limits) values were 196 ng/g egg (188–203 ng/g) for shovelnose and 159 ng/g egg (122–199 ng/g) for pallid sturgeon. Likewise, calculated TCDD LD50 values were 13 ng/g egg (11–15 ng/g) for shovelnose and 12 ng/g egg (10–14 ng/g) for pallid sturgeon. These LD50 values are among the highest recorded in early life stage fish, suggesting that early life stage Scaphirhynchus sturgeon may be comparatively insensitive to AhR agonists.

Environmental Toxicology and Chemistry↗

USGS2011

Effects of flow dynamics on the aquatic-terrestrial transition zone (ATTZ) of lower Missouri river sandbars with implications for selected biota

Sandbars are an important aquatic terrestrial transition zone (ATTZ) in the active channel of rivers that provide a variety of habitat conditions for riverine biota. Channelization and flow regulation in many large rivers have diminished sandbar habitats and their rehabilitation is a priority. We developed sandbar-specific models of discharge-area relationships to determine how changes in flow regime affect the area of different habitat types within the submerged sandbar ATTZ (depth) and exposed sandbar ATTZ (elevation) for a representative sample of Lower Missouri River sandbars. We defined six different structural habitat types within the sandbar ATTZ based on depth or exposed elevation ranges that are important to different biota during at least part of their annual cycle for either survival or reproduction. Scenarios included the modelled natural flow regime, current managed flow regime and two environmental flow options, all modelled within the contemporary river active channel. Thirteen point and wing-dike sandbars were evaluated under four different flow scenarios to explore the effects of flow regime on seasonal habitat availability for foraging of migratory shorebirds and wading birds, nesting of softshell turtles and nursery of riverine fishes. Managed flows provided more foraging habitat for shorebirds and wading birds and more nursery habitat for riverine fishes within the channelized reach sandbar ATTZ than the natural flow regime or modelled environmental flows. Reduced summer flows occurring under natural and environmental flow alternatives increased exposed sandbar nesting habitat for softshell turtle hatchling emergence. Results reveal how management of channelized and flow regulated large rivers could benefit from a modelling framework that couples hydrologic and geomorphic characteristics to predict habitat conditions for a variety of biota.

River Research and Applications↗

USGS2008

Design of a naturalized flow regime—An example from the Lower Missouri River, USA

group of river managers, stakeholders, and scientists met during summer 2005 to design a more naturalized flow regime for the Lower Missouri River (LMOR). The objective was to comply with requirements under the U.S. Endangered Species Act to support reproduction and survival of threatened and endangered species, with emphasis on the endangered pallid sturgeon ( Scaphirhynchus albus ), while minimizing negative effects to existing social and economic benefits of prevailing river management. Specific hydrograph requirements for pallid sturgeon reproduction are unknown, hence much of the design process was based on features of the natural flow regime. Environmental flow components (EFCs) extracted from the reference natural flow regime were used to design and assess performance of alternative flow regimes. The design process incorporated a primary stage in which conceptual hydrographs were developed and assessed for their general ecological and social-economic performance. The second stage accounted for hydroclimatic variation by coding the conceptual hydrographs into reservoir release rules, adding constraints for downstream flooding and low-storage precludes, and running the rules through 100 years of hydroclimatic simulation. The output flow regimes were then evaluated for presumed ecological benefits based on how closely they resembled EFCs in the reference natural flow regime. Flow regimes also were assessed for social-economic cost indicators, including days of flooding of low-lying agricultural land, days over flood stage, and storage levels in system reservoirs. Our experience with flow-regime design on the LMOR underscored the lack of confidence the stakeholders place in the value of the natural flow regime as a measure of ecosystem benefit in the absence of fundamental scientific documentation. Stakeholders desired proof of ecological benefits commensurate with the certainty of economic losses. We also gained insight into the processes of integrating science into a collaborative management exercise. Although the 2005 collaborative effort failed to reach a consensus among stakeholders on a naturalized flow regime, the process was successful in pilot-testing a design approach; it helped focus scienctific efforts on key knowledge gaps; and it demonstrated the potential for collaborations among scientists, stakeholders, and managers in river management decision making.

Lower Missouri River↗

USGS2007

A conceptual life-history model for pallid and shovelnose sturgeon

Intensive management of the Missouri and Mississippi Rivers has resulted in dramatic physical changes to these rivers. These changes have been implicated as causative agents in the decline of pallid sturgeon. The pallid sturgeon, federally listed as endangered, is endemic to the turbid waters of the Missouri River and the Lower Mississippi River. The sympatric shovelnose sturgeon historically was more common and widespread than the pallid sturgeon. Habitat alteration, river regulation, pollution, and over-harvest have resulted in the now predictable patterns of decline and localized extirpation of sturgeon across species and geographic areas. Symptomatic of this generalized pattern of decline is poor reproductive success, and low or no recruitment of wild juveniles to the adult population. The purpose of this report is to introduce a conceptual life-history model of the factors that affect reproduction, growth, and survival of shovelnose and pallid sturgeons. The conceptual model provided here was developed to organize the understanding about the complex life history of Scaphirhynchus sturgeons. It was designed to be used for communication, planning, and to provide the structure for a population-forecasting model. These models are intended to be dynamic and responsive to new information and changes in river management, thereby providing scientists, stakeholders, and managers with ways to improve understanding of the effects of management actions on the ecological requirements of Scaphirhynchus sturgeons. As new scientific knowledge becomes available, it could be included in the model in many ways at various integration levels.

Circular↗

USGS2006

Reproductive development in the sicklefin chub in the Missouri and Lower Yellowstone Rivers

We describe aspects of sicklefin chub (Macrhybopsis meeki) reproductive development from three study areas encompassing greater than 2,700 km of the Missouri and Lower Yellowstone rivers. The sicklefin chub was collected between late July and early October in 1996 and 1997. A total of 193 sicklefin chub was collected and examined for reproductive characteristics. Twenty-nine sicklefin chub were found to be reproductively mature females. Some sicklefin chub matured at age 2, but most matured at age 3 and all matured by age 4. Females first became mature at 70 to 79 mm total length (TL) in the Upper Missouri River reach in central Montana, 80 to 89 mm TL in the Missouri and Lower Yellowstone rivers in eastern Montana-western North Dakota, and 90 to 99 mm TL in the lower Missouri River in Nebraska, Iowa, Kansas, and Missouri. Gonad mass of gravid females averaged 6.9% of total body mass and ranged from 1.7 to 13.5%. Total number of oocytes per female, ranged from 7 to 1,561. Reproductive development of the sicklefin chub appeared to be group synchronous or synchronous indicating multiple spawnings during a spawning season. This variability in spawning mode required cautious interpretation of gonadosomatic index values and oocyte counts as estimates of total fecundity, because some females might have released a cohort of oocytes prior to their capture.

The Prairie Naturalist↗

USGS2003

A comparison of measures of riverbed form for evaluating distributions of benthic fishes

A method to quantitatively characterize the bed forms of a large river and a preliminary test of the relationship between bed-form characteristics and catch per unit area of benthic fishes is presented. We used analog paper recordings of bathymetric data from the Missouri River and fish data collected from 1996 to 1998 at both the segment (???101-102-km) and macrohabitat (???10-1-100-km) spatial scales. Bed-form traces were transformed to digital data with image analysis software. The slope, mean residual, and SD of the residuals of the regression of depth versus distance along the bottom, as well as mean depth, were estimated for each trace. These four metrics were compared with sinuosity, fractal dimension, critical scale, and maximum mean angle for the same traces. Mean depth and sinuosity differed among segments and macrohabitats. Fractal-based measures of the relative depth of bottom troughs (critical scale) and smoothness (maximum mean angle) differed among segments. Statistics-based measures of the relative depth of bottom troughs (mean residual) and smoothness (SD of the residuals) differed among macrohabitats. Sites with shovelnose sturgeon Scaphirhynchus platorynchus were shallower and smoother than sites without shovelnose sturgeon. When compared with sites without sicklefin chub Macrhybopsis meeki, sites with sicklefin chub were shallower, had shallower troughs, and sloped more out of the flow of the river. Sites with sturgeon chub M. gelida were shallower, had shallower troughs, and were smoother than sites without sturgeon chub. Sites with and without channel catfish Ictalurus punctatus did not differ for any bed-form variables measured. Nonzero shovelnose sturgeon density increased with depth, whereas nonzero sturgeon chub density decreased with depth. Indices of bed-form structure demonstrated potential for describing the distribution and abundance of Missouri River benthic fishes. The observed fish patterns, though limited, provide valuable direction for future research into the habitat preferences of these fishes.

North American Journal of Fisheries Management↗

USGS2002

Fish mortality and physicochemistry in a managed floodplain wetland

Patterns of fish mortality and associated physicochemical factors were studied during late spring in a managed wetland canal along the lower Missouri River, Missouri. Mean dawn dissolved oxygen was lower and mean un-ionized ammonia and turbidity were higher during the fish kill than before or after the kill, or than was observed in a nearby wetland canal where no fish kill occurred. Dissolved oxygen at dawn and un-ionized ammonia concentrations were at critically low and high levels respectively, so that both likely contributed to the fish mortality. Timing and magnitude of observed carcasses suggested that Ameiurus melas Rafinesques was the most tolerant species for the sizes observed compared to Ictiobuscyprinellus Valenciennes, Lepomis macrochirus Rafinesque, Cyprinus carpio Linneaus, and Lepomis cyanellus Rafinesque. Decreasing mean lengths of fish carcasses during the fish kill for C.carpio, L. cyanellus , and A. melas , indicate that smaller fishes may have been more tolerant of harsh environmental conditions than larger individuals of the same species. Differential mortalities among species and sizes during drawdowns in actively managed wetland pools may have intentional and unintentional ramifications on wetland and riverine fish community structure, fish-avian interactions, and implementing an ecosystem management perspective to restoring more naturalized river floodplain wetland functions. Late summer and early autumn draining of managed wetlands might be used to benefit a wider diversity of wildlife and fishes.

Wetlands Ecology and Management↗

USGS1999

Fishes of Missouri River, chute, and flood plain habitats: Chapter 4 in Initial biotic survey of Lisbon Bottom, Big Muddy National Fish and Wildlife Refuge

The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge (Refuge) is approximately 2,200 acres and is the first complete unit of the Refuge. Primary objectives of the Refuge are to create and restore diverse riverine aquatic habitats and reconnect the Missouri River to its flood plain where feasible. Management seeks to accomplish these objectives by encouraging natural processes of erosion, deposition, and succession to the greatest extent possible. One of the most salient aquatic features of the Lisbon Bottom Unit is a newly created 2-mile-long free-flowing chute, or side channel (Fig. 1). This chute began forming as a levee breech scour hole during the Great Flood of 1993. The chute continued to develop during the 1995 flood and finally cut through to a flowing side channel during the 1996 flood. Extensive erosion and bank sluffing continued during 1997 due to sustained high flows that occurred throughout most of the year. The chute has progressively become wider and deeper with a developing meander pattern and channel bars have begun to form. Lisbon Bottom also contains several seasonal and permanent wetlands and is subject to periodic flooding at high Missouri River stages. Eight studies have been completed or are ongoing to evaluate Missouri River fishes associated with various habitat components of Lisbon Bottom and adjacent Missouri River reaches (Table 1). Several are part of much larger investigations to evaluate fish use of flood-created habitat features, basinwide fish assessment, and endangered or candidate species concerns. At the Lisbon Bottom Unit or in the Missouri River adjacent to the unit 54 fish species were collected (Table 2). Eight of these species have either a protected status under State or Federal laws or biologists consider them to potentially qualify for protected status. The status of the following fish is listed in Table 2: pallid sturgeon x shovelnose sturgeon hybrid, paddlefish, northern pike, sturgeon chub, sicklefin chub, ghost shiner, western silvery minnow, plains minnow, and blue sucker. Equally important to note are fish species that were not collected. The flathead chub, currently listed as State endangered and proposed for Federal listing, were not collected in any of the studies. Common fish species, collected in all seven sampling studies, included gizzard shad, common carp, river carpsucker, and freshwater drum. Paddlefish, skipjack herring, silver carp, white sucker, redfin shiner, western silvery minnow, bullhead minnow, and black bullhead were each collected in only one of the seven studies. Pflieger (1971) developed a guild system for the fishes of Missouri based on distribution patterns and centers of abundance. Fish were assigned to one of four primary faunal groups: Ozark, Big River, Lowland, and Prairie. Two secondary groups (Ozark-prairie and Ozark-lowland) were defined for species equally abundant and distributed in two of the primary areas. Two Ozark-prairie species, shorthead redhorse and white sucker, were collected on or near the Lisbon Bottom Unit. Big River species are found primarily in the Missouri and Mississippi Rivers. The environmental factors controlling fish distribution in these rivers appear to be substrate, current velocity, and turbidity. On or near the Lisbon Bottom Unit 18 Big River species were collected (Table 2). Lowland species are intolerant of siltation and high turbidity. They inhabit standing or slow-moving water with sand, fine gravel, and organic debris substrates. Two Lowland species, bullhead minnow and mosquitofish, were collected in connected scours on the Lisbon Bottom Unit. Prairie species have broader ecological tolerances than the Ozark and Lowland species. They are largely absent in high gradient streams and cool, clear waters. Prairie species make up a significant proportion of Missouri and Mississippi River fishes. Seven Prairie species were collected on or near the Lisbon Bottom Unit (Table 2). The last group, Wide-ranging, was defined as the species more widespread than the other faunal groups with broader environmental tolerances. Most Wide-ranging species occur at least occasionally in all sections of the state. Nineteen Wide-ranging species were collected on or near the Lisbon Bottom Unit (Table 2). Kubisiak (1997) found that isolated scours in the Lower Missouri River were dominated by Wide-ranging species. Connected scours also held Wideranging species but they contained Prairie species and were dominated by Big River species. Faunal group diversity and species richness were compared between isolated (Study l) and connected (Studies 4, 5, 7, and 8) scours of the Lisbon Bottom Unit. Species richness was similar with 22 species collected in isolated scours and an average of 24.8 species collected in connected scours. Isolated scour fish catches were dominated by Wide-ranging fish (59%) with 14% Big River fishes and 14% Prairie fishes. Connected scours had a larger percentage of Big River fish (32%) and fewer Wide-ranging (36%) and Prairie (13%) species than the isolated scours. In the combined studies, Wide-ranging fish dominated the connected scours. A similar comparison was made of fish from chute habitats and the Missouri River. Chute habitats include the Lisbon Bottom Chute, the chute between the right bank and island located at river mile 219, and a shallow channel running between a large sandbar complex and the channel border adjacent to Lisbon Bottom. Species richness in the chutes (35 species) was greater than that of the adjacent river (23 species). Big River species (40%) dominated the chute samples, followed by Wide-ranging at 31% Cand Prairie Cut 14%. The river samples contained equal numbers of Wide-ranging species (35%) and Big River species (35%) with 17% Prairie species. Differences in fish guild diversity and species richness may be due to numerous factors including sampling effort and sampling season. River samples were collected only in Study 3 in October; chute samples were collected in July, August, and October. Fish may have been using the chute in July and August to spawn, feed, or escape high river levels. The Lisbon Bottom Chute is a truly unique feature of the Lower Missouri River. It is the first naturally created side channel to develop since the U.S. Army Corps of Engineers tamed the river. The Corps eliminated 89% of the islands in the Missouri River between 1879 and 1954 (Funk and Robinson 1974). The chutes between the islands and the shore were shallower with less current than the main channel. These areas provided diversity to the Missouri River fish habitat, serving as nursery and feeding areas. The Lisbon Bottom Unit of the Big Muddy National Fish and Wildlife Refuge will continue to be studied in an effort to understand the complex role these areas play in river systems.

Missouri↗