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At least 541 records · Page 30Linked to original sources
USGS2025

Postrelease movements of captive-reared adult Atlantic Salmon in two Maine rivers

Objective Atlantic Salmon Salmo salar remain at critically low levels in the United States, with the last remaining populations located in the state of Maine. In 2021, a pilot captive-rearing program, similar to a smolt-to-adult supplementation, was implemented to boost naturally spawning adults in support of recovery goals. Methods We conducted a 2-year acoustic telemetry study to track a subset of captive-reared salmon ( N = 270) that were released into the Penobscot and Machias rivers. We evaluated their postrelease movement patterns, dam passage, and site fidelity between the two rivers, years, and seasons. Results Atlantic Salmon that were released into the Penobscot River tended to overwinter, but their movement patterns varied between release years. In contrast, the Atlantic Salmon that were released into the Machias River were more likely to move directly downstream to the river exit. In addition, the fish that were released into the dammed Penobscot River frequently made multiple attempts to pass dams in both directions, often with passage delays and failures. Atlantic Salmon that were released during the summer displayed more exploratory movements than those that were released in the fall. Most Atlantic Salmon either left the river shortly after release (5–30 d) or the following spring (>120 d). Site fidelity was greater for the fall-released Atlantic Salmon (76%) than for the summer-released Atlantic Salmon (23%). Conclusions Overall, releasing salmon in the fall as sexually mature adults may increase site fidelity to the release reach, thereby enhancing the chances of successfully spawning in the wild.

Maine↗
USGS2025

Seasonal movements of nonnative White Catfish in the Penobscot River estuary

Objective White Catfish Ameiurus catus has been introduced to coastal watersheds across the United States. In the Penobscot River, Maine, this species has become increasingly common in upstream habitats that have been made accessible by recent dam removals. We characterized the movements of White Catfish to understand the temporal variation in their movement patterns and contextualize these findings within the recent changes in watershed connectivity. Methods We captured and tagged 10 adult White Catfish (mean fork length = 271 mm) with acoustic transmitters in the lower Penobscot River in July 2022. The movements of the tagged fish were monitored through April 2023 with a large network of stationary receivers. Results The tagged catfish were detected up to 6 km upstream and 31 km downstream from the release site. The total distance that was traveled by individuals ranged from 0 to 154 km during the study. Fall and spring movements were associated with changes in river flow and water temperature, but fish were relatively stationary from December through March, when at least five individuals were assumed to have overwintered in lower river tributaries. Conclusion Our results show that individual White Catfish may move considerable distances within large river systems and that these movements are potentially facilitated by changing river conditions. Collectively, this study fills a long-standing knowledge gap about the movement ecology of this species, adds context to help explain a recent increase in observations within their introduced range, and shows how changes in river conditions may be used to predict when and where these fish will move within a tidal system.

Maine↗
USGS2025

Estimating recruitment of Largemouth Bass to exceptional weights using angler-reported catches

ABSTRACT Objective Although most facets of Largemouth Bass Micropterus nigricans ecology have been researched, the upper tiers of weight distributions (i.e., ≥3.6 kg; herein, “lunkers”) have received little attention due to the challenges of collecting sufficient sample sizes. Our aim was to estimate Largemouth Bass recruitment to higher weights after reaching 3.6 kg and to identify factors correlated with such recruitment. Methods We used an online database of angler-reported catches to investigate recruitment of Largemouth Bass after reaching lunker size and to identify associated factors. Recruitment was indexed by the slopes of the reversed cumulative counts relative to increasing weights, with gentler negative slopes indicating higher recruitment. The influence of environmental variables on these slopes identified the factors associated with recruitment. Results An average of 20% (minimum = 4%; maximum = 45%) of lunker bass were estimated to recruit after reaching 3.6 kg. When expanded, these estimates revealed that recruitment from 3.6 to 4.5 kg averaged 23.5% and recruitment from 3.6 to 5.9 kg averaged 2.5%. The observed recruitment was positively correlated with the frequency of Florida Bass M. salmoides alleles in the population and was inversely correlated with human population densities in the vicinity of the reservoir and with chlorophyll- a concentrations in the environment. Conclusions Recruitment of Largemouth Bass after reaching 3.6 kg appears to require a nuanced equilibrium enabled by a higher frequency of Florida Bass alleles, a remote location of the fishery, and a reservoir trophic state that balances adequate environmental conditions and food supply.

North American Journal of Fisheries Management↗
USGS2025

Carbon and nitrogen isotopes of different native fish tissues from the Santa Ana River, California

Objective Stable isotopes are commonly used to understand the role of fishes in aquatic food webs. However, variability in species- and tissue-specific isotopic values can affect the inference that is drawn from a stable isotope study. We evaluated differences in stable isotopes of carbon (δ 13 C) and nitrogen (δ 15 N) among three tissue types (white muscle, caudal fin rays, and eye lenses) for Santa Ana Sucker Pantosteus santaanae and Arroyo Chub Gila orcuttii to inform the design of a stable isotope study in the Santa Ana River, an urban river that is located in southern California. Methods We used multivariate analyses to test for differences in the stable isotopes of carbon (δ 13 C) and nitrogen (δ 15 N) among the three tissue types that were collected from Santa Ana Sucker and Arroyo Chub. We also summarized the variability in isotopic values that was recorded over time in fish eye lenses and interpreted this variability in reference to the spatial patterns in isotopic values that have been previously reported throughout the Santa Ana River. Results We found that fin ray tissue and white muscle tissue were not significantly different for either isotope or fish species. Fish eye lenses were significantly higher in δ 13 C than muscle tissue, and eye lenses were significantly higher in δ 15 N than fin ray tissue for both fishes. We also found a greater range in δ 13 C and δ 15 N across eye lens layers for Santa Ana Sucker (δ 13 C = 2.01 ± 0.96‰, δ 15 N = 4.93 ± 4.18‰) than for Arroyo Chub (δ 13 C = 0.96 ± 0.65‰, δ 15 N = 4.63 ± 1.45‰). Conclusion Our results indicate that fin rays may be a viable nonlethal alternative to white muscle tissue for use in a stable isotope study of native fish of the Santa Ana River. Additionally, eye lenses could provide a chemical history of fishes within the river, but species-specific correction factors may be needed if stable isotope values for eye lenses are to be compared with more conventional tissue types (e.g., white muscle).

California↗
USGS2025

Muskellunge spawning habitat characteristics and availability in Green Bay, Lake Michigan

Objective Habitat degradation has been associated with the loss of many self-sustaining Muskellunge Esox masquinongy populations, including those in Green Bay, where stocking has provided an exceptional trophy fishery but restoration goals include establishing self-sustaining populations and there is little evidence of natural recruitment. Our objectives were to determine whether (1) Muskellunge spawning locations and occurrence of successful hatching were related to a suite of habitat characteristics, (2) proportions of Muskellunge spawning in or outside of tributaries to lower Green Bay were different, and (3) Muskellunge showed spawning site fidelity. Methods From 2017 to 2019, adult Muskellunge ( N = 60) were surgically implanted with radio and acoustic transmitters to identify spawning locations, where we measured a suite of habitat variables and attempted to collect eggs and larvae. Side-scan sonar was used to quantify the amount of habitat available to Muskellunge for egg deposition in the Fox and Menominee rivers, which are tributaries to Green Bay. Results Muskellunge eggs were collected at 58 locations, but only two larvae were collected from a single location. Bottom slope, depth, distance to shore, gravel substrate, organic matter, and dissolved oxygen best predicted the presence of Muskellunge eggs. We determined that little habitat associated with Muskellunge egg deposition was available in the Fox and Menominee rivers. However, approximately half of tagged Muskellunge appeared to spawn outside of tributaries. Muskellunge in Green Bay displayed moderate spawning site fidelity. Conclusions Our results suggest that successful hatching occurs at very low levels and the lack of suitable Muskellunge spawning habitat in Green Bay tributaries may be limiting natural reproduction. Changes in spatial allocation of stocked fish and enhancement of known spawning locations may increase egg deposition and subsequent natural reproduction.

Michigan, Wisconsin↗
USGS2025

Hatchery rearing density affects poststocking survival

Objective Research has indicated that salmonids raised in a hatchery and stocked into the wild have lower future survival and reproductive success than wild fish. Understanding whether hatchery rearing practices affect populations after stocking can help to maximize the quality, quantity, and economic value of fish stocked for conservation and recreational purposes. The goal of our study was to test whether and to what extent rearing density affects poststocking survival of Rainbow Trout Oncorhynchus mykiss when stocked into a put-grow-and-take fishery. Methods Rainbow Trout were raised for 3 months in the hatchery at two densities (high = 51,948–13,072 fish/m 3 , rearing index 2.0, 1,260 metric units; low = 12,987–3,268 fish/m 3 , rearing index 0.5, 315 metric units). A subset of the fish were PIT-tagged and stocked into Parvin Lake, Red Feather Lakes, Colorado. Recaptures of tagged fish occurred every 2 weeks for the first 2 months poststocking and at 7 and 12 months poststocking. Results At the time of stocking, there were no statistical differences in Fulton’s condition factor, total length, weight, or hepatosomatic index for each treatment. Recapture data indicated that there was no difference in Fulton’s condition factor and hepatosomatic index after stocking. Apparent poststocking survival was higher for fish raised at low density in the hatchery compared with those raised at high density. Conclusions Our study suggests that rearing density affects fingerling Rainbow Trout poststocking survival. Stocking more fish due to fish being reared at higher densities within the hatchery did not result in more total fish remaining after a year in the lake compared with the low-density treatment. Rearing fish at high densities does not provide a benefit of more fish after stocking and may result in more disease risk in the hatchery.

Colorado↗
USGS2025

Trophic assessment of potential competition between invasive cichlids and sport fish in Puerto Rico reservoirs

Objective Several species of New World cichlids have recently invaded reservoirs in Puerto Rico, potentially jeopardizing established recreationally important, albeit nonnative, sport fish populations. Interactions between invasive species and important sport fish must be understood so that they can be mitigated when feasible. This study compared monthly prey consumption between three invasive cichlids (Jaguar Guapote Parachromis managuensis and two species of Amphilophus ) and two principal sport fishes (Largemouth Bass Micropterus nigricans and Butterfly Peacock Bass Cichla ocellaris ) to understand potential for competitive interactions. Methods Stomach contents were evaluated quarterly using gastric lavage for sport fish and destructive sampling techniques for invasive species. Prey proportion by mass was calculated for each individual, and mean prey proportion by mass was calculated for each species by reservoir, month, and overall. Multivariate hypothesis testing using permutational multivariate analysis of variance and visualization of potential diet overlap were performed via analysis of variance and nonmetric multidimensional scaling (NMDS), respectively. Results Fish were the most common prey type, and Threadfin Shad Dorosoma petenense was the most prevalent prey species. Although there were significant differences in diets of invasive cichlids and sport fishes ( P < 0.01), there also was considerable overlap based on low percentages of variation in diets explained by species (3–19% < pseudo- R 2 ) and NMDS visualizations. Diets varied little across reservoirs and months (≤4% pseudo- R 2 ; high overlap in NMDS space). Conclusion These data indicate that the diet of Jaguar Guapote and Amphilophus spp. may overlap with that of sport fish populations in Puerto Rico. Jaguar Guapote relied on Threadfin Shad more than other species, with Amphilophus spp. relying more on detritus and noncrayfish invertebrates. Thus, if prey are limited, Jaguar Guapote may have a more direct effect via competition for prey. Finally, we report evidence of Largemouth Bass recruitment failure and local extirpations that support a hypothesis that invasive cichlids are having negative effects on at least Largemouth Bass, although the mechanism is unclear.

Puerto Rico↗
USGS2026

Evaluating alternative methods for modeling trap efficiencies of out-migrating juvenile salmonids

Objective We aimed to compare two machine learning approaches—boosted beta regression (BBR) and beta mixed model forest (BMF)—to a Bayesian mixed-effects beta regression (BME) for the prediction of rotary screw trap (RST) efficiency for out-migrating juvenile salmonids from environmental covariates. Methods We identified two machine learning approaches that shared the ability to model overdispersed probabilities. We compared the BBR and BMF machine learning models to a BME model to evaluate precision in detection probability prediction and model performance on bias in parameter estimation. We tested our three candidate models using a simulation study to understand the specific advantages and disadvantages of each when the data set was increasingly sparse and the capture probabilities were realistically small. We then applied the models to a case study of RST data from the Klamath River in California, United States. Results The BME and BMF outperformed BBR in all simulated scenarios, although the BMF displayed poor explanatory power. In the case study, the BME and BMF identified environmental covariates that predicted RST efficiency. Conclusions Using the BME as a benchmark for comparing machine learning approaches to trap efficiency modeling, our simulations and case study demonstrated that the BMF performed well and is a viable modeling approach with strong predictive power. The BME model would be the preferred modeling approach when its strong explanatory power is desired.

North American Journal of Fisheries Management↗
USGS2026

Lake Trout population dynamics on Six Fathom Bank and Yankee Reef in Lake Huron, 1992–2023

Objective Under the auspices of the Great Lakes Fishery Commission, the Lake Huron Committee and its technical committee initiated offshore stocking of Lake Trout Salvelinus namaycush beginning in 1985 as an additional step toward restoring a self-sustaining Lake Trout population to the lake, with stocking occurring first at Six Fathom Bank and then later at Yankee Reef. The goal of this study was to assess progress toward Lake Trout rehabilitation on Six Fathom Bank and Yankee Reef in Lake Huron through 2023. Methods We conducted annual (1992–2023) gill-net surveys in the spring–summer and the fall to assess juvenile and adult populations, as well as beam trawl surveys in the spring–summer to detect naturally reproduced age-0 Lake Trout. Result During 2000–2015, relative abundance of unclipped (wild) Lake Trout surged from levels of <2 fish · 305 m of gill net −1 · d −1 to levels exceeding 50 fish · 305 m of gill net −1 · d −1 on both Six Fathom Bank and on Yankee Reef, based on fall gill-net surveys, and has remained at a relatively high level through 2023. The proportion of wild fish in both the spring gill-net surveys and the fall gill-net surveys averaged well over 50% in the Six Fathom Bank–Yankee Reef (SFBYR) complex during 2014–2023. Sea Lamprey Petromyzon marinus wounding rate in the SFBYR complex decreased from 20 wounds/100 fish during 1994–2002 to just 7 wounds/100 fish during 2004–2023, based on the fall gill netting. Annual mortality rate estimates for SFBYR adult Lake Trout during the 2004–2023 period averaged 21%. Wild age-0 Lake Trout were captured in beam trawls in the SFBYR complex during the 1994–2022 period, providing further evidence that Lake Trout were actively spawning within this offshore reef complex. Conclusion Based on several metrics, the SFBYR Lake Trout population appeared to be self-sustaining. Lake Trout stocking, Sea Lamprey control, and restrictions on fishing for Lake Trout played important roles in the population recovery. The lessening of the negative effect of Alewives Alosa pseudoharengus on Lake Trout natural recruitment was likely a key factor in the restoration process.

Lake Huron, Six Fathom Bank, Yankee Reef↗
USGS2026

Indicators of mercury concentration in Lake Trout: Can fish location and appearance provide information to anglers to reduce their exposure?

Objective People are exposed to mercury (Hg) through the consumption of fish. State and federal governments provide broad, often-generalized food safety guidance to reduce exposure; however, numerous rural fishing areas lack testing and location- or species-specific guidance. The aim of this study was to provide tangible, visible, or easily measured characteristics of Lake Trout Salvelinus namaycush that could convey information on Hg exposure to people harvesting and consuming fish where no location-specific guidance exists. Methods We investigated potential indicators of Lake Trout total Hg (THg) concentrations in muscle across 10 lakes in Alaska's national parks. Potential indicators, including lake, lake zone (i.e., littoral, pelagic, profundal), fish length, head size, body condition, and general appearance, were evaluated by competing linear mixed-effects models. Results Lake Trout THg concentrations ranged widely from 22 to 1,306 ng/g wet weight. Much of the variation (48%) in THg concentrations was attributed to differences among individual lakes, but the interaction of the fish's lake zone, body length, and head size accounted for an additional 21%. Predicted THg concentrations increased with Lake Trout length and head : body proportion, but the rate of THg concentration increase with length varied by head : body proportion and lake zone. Conclusions Given the overwhelming evidence of high lake-to-lake variability in Lake Trout THg concentrations, we find support for use of lake-specific guidance when data are available. When lake-specific THg concentrations are not available, the best potential way to reduce exposure is to harvest and consume Lake Trout with mean predicted THg concentrations that are within state and federal safe consumption guidelines. This included Lake Trout from surface waters (i.e., pelagic or littoral zone) that are ≤70 cm in length; if harvesting fish from deep waters (i.e., profundal zone), lower THg concentrations were found in Lake Trout with heads ≤25% of their body length. The indicators—lake zone, length, and head size—of Lake Trout THg concentrations can provide harvesters with additional information in the absence of data for specific lakes.

Alaska↗
USGS2026

Validation of daily age in Grass Carp reared in tanks and outdoor ponds in the U.S. Midwest

Objective Accurate and precise age estimation is essential for understanding early life history, recruitment, and population dynamics in fish. However, daily otolith increment deposition has not been validated for Grass Carp Ctenopharyngodon idella in the Midwestern United States. Our objective was to validate daily increment deposition in lapilli otoliths of known-age Grass Carp that were reared under controlled laboratory and outdoor pond environments and to evaluate the reliability of otolith-based daily age estimation across early life stages. Methods Larval Grass Carp that were hatched from captive broodstock were reared in indoor tanks and outdoor ponds and sampled between 6 and 120 d posthatch. The lapilli otoliths were extracted, lightly sanded, and independently read three times to estimate age. The estimated ages were compared with known chronological age to assess the accuracy and precision of daily increment counts across rearing environments. Results Daily increment deposition was validated through 51 d posthatch for the tank-reared fish and through 69 d posthatch for the pond-reared fish. Beyond these ages, the estimated ages increasingly underestimated known age due to compression of daily increments near the otolith core and outer margin, particularly in slower growing individuals. Growth rates differed substantially between the two rearing environments and influenced increment spacing and readability. Otolith size was strongly correlated with the total length of the fish but decreased relative to chronological age as increment compression increased, particularly in fish exceeding approximately 40–50 mm total length (TL) in tank-reared and 60–70 mm TL in pond-reared individuals. Conclusions Lapilli otoliths provide reliable daily age estimates for Grass Carp during early life stages under both laboratory and pond conditions. These validated methods enable robust estimation of hatch timing and early growth, providing a foundational tool for studying early life history and informing control efforts for invasive Grass Carp populations

Missouri↗
USGS2026

Describing Yellow Perch population characteristics in Wisconsin to better understand observed declines in size structure

Objective Recent studies suggest that Yellow Perch Perca flavescens size structure has declined in Wisconsin and Minnesota. Little is known about most of the Yellow Perch populations that exist across the upper Midwestern USA because Yellow Perch are not a focus of standardized sampling and age estimation rarely occurs. To better understand Yellow Perch population dynamics and demographics, we described age- and length-based characteristics of 31 Yellow Perch populations in Wisconsin and assessed potential correlations with abiotic and biotic variables. Methods During 2018–2019, Yellow Perch were collected from 31 populations during spring fyke-net surveys to calculate mean total length (TL) at age 4 (ML4), maximum age, proportional size distribution (PSD), and mean TL of the five largest fish (MXL5). Pearson correlations were used to identify associations among these metrics and with a suite of abiotic and biotic variables. Results Mean TL at age 4 was <175 mm for 54% of our study populations, median maximum age was 8 years, median PSD was 15, and median MXL5 was 229 mm TL. There were positive correlations among ML4, PSD, and MXL5 and between maximum age and MXL5. Yellow Perch metrics were not correlated with catch per effort of Walleye Sander vitreus , Largemouth Bass Micropterus nigricans , or Bluegill Lepomis macrochirus . Yellow Perch population metrics were generally not correlated to environmental variables except for ML4, which was positively correlated to shoreline development index and maximum age, which was negatively correlated to growing degree-days and lake surface area. Conclusions Many Wisconsin Yellow Perch populations we evaluated were slow growing with low size structure and limited capacity to produce fish ≥200 mm TL. Populations where PSD is ≥32 and MXL5 ≥245 mm TL may represent exceptional opportunities for anglers to catch relatively large fish and could warrant additional investigation to identify factors contributing to high size structure.

Wisconsin↗
USGS2026

Arctic Grayling, scared to death: Are Brown Trout an impediment to Arctic Grayling reintroduction success in Michigan?

Introduction: Arctic Grayling Thymallus arcticus were extirpated from Michigan in 1936. Their demise was caused by over-fishing, habitat destruction from large-scale logging, and Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta. Subsequently, Brook and Brown trout have become the dominant salmonid species in Michigan streams. Past attempts to restore Grayling to Michigan have been unsuccessful perhaps due to competition with these now resident salmonids. Objective: To determine the impacts of competition between age-0 Arctic Grayling and age-0 Brook and Brown Trout on Grayling growth and survival. Methods: Competition trials were performed in experimental streams, lasting two months, across three years, with three treatment types: the control, 10 Grayling with 10 Grayling; the Brook Trout treatment, 10 Grayling with 10 Brook Trout; and the Brown Trout treatment, 10 Grayling with 10 Brown Trout. Results: Brown Trout had a significant effect on Arctic Grayling growth and mortality, while Brook Trout had no effect on Arctic Grayling growth or mortality. Conclusion: Age-0 Brown Trout negatively impacted growth, condition, and survival of age-0 Arctic Grayling, while the impacts of age-0 Brook Trout or conspecifics were negligible. This suggests reintroduction of Arctic Grayling may be more successful in streams with few or no Brown Trout.

Michigan↗
USGS2026

Water and endangered fish in the Klamath River basin revisited: Does old age or Upper Klamath Lake surface elevation and water quality affect adult Lost River Sucker and Shortnose Sucker survival? A response to Kann and Walker

Our update responds to recent scientific critiques and again finds no evidence that lake levels or water conditions influence adult sucker survival. This reaffirms our prior work (Krause et al., 2022) and suggests that recent declines in adult survival may reflect an aging population.

Oregon↗
USGS1981

The commercial fishery for walleyes in New York waters of Lake Erie, 1959-1978

A limited commercial gill-net fishery for walleyes (Stizostedion vitreum vitreum) in New York waters of Lake Erie was established in the 1950's. Since then year class strengths have varied considerably; four have been outstanding- those of 1959, 1962, 1964, and 1971. A rapid rate of rise in water temperature during spawning and incubation was positively correlated with the strength of these year classes. Each time a strong year class appeared, small-mesh gill-net effort was markedly increased, and an average of 46% of the fish of each year class was harvested at age I before they were sexually mature. If the smallmesh gill-net fishery had not been operating, the total annual production by the largemesh gill-net fishery could have been increased by an average of 35%.

North American Journal of Fisheries Management↗
USGS1981

Substrate conditions and abundance of lake trout eggs in a traditional spawning area in southeastern Lake Michigan

Spawning by planted lake trout (Salvelinus namaycush) was documented by sampling with a diver-assisted pump in a traditional spawning area in southeastern Lake Michigan near Saugatuck, Michigan in mid-November in 1978 and 1979. Bottom depths at the 11 locations sampled ranged from 3 to 12 m and substrate size from boulders to sand. Periphyton (Cladophora and associated biota) was several millimeters thick at most stations but sparse at the shallowest. The most eggs recovered from a single sample occurred at the shallowest depth (3 m). In both years, some of the small numbers of eggs collected (9 in 1978, 14 in 1979) were alive and fertilized. Laboratory incubation of viable eggs resulted in successful hatching of larvae. When compared with egg densities measured at spawning sites used by self-sustaining populations of lake trout in other lakes, densities in the study are (0-13/m 2 ) appeared to be critically low. Insufficient numbers of eggs, combined with harsh incubation conditions (turbulence, ice scour, sedimentation), were implicated as prime causes for lake trout reproductive failure in the study area, although other factors, such as inappropriate spawning behavior (selection of suboptimal spawning location, depth, or substrate) also may have reduced survival of eggs and larvae.

Lake Michigan↗
USGS1982

Effects of an aquatic plant and suspended clay on the activity of fish toxicants

Rotenone, antimycin, permethrin, pydrin, and Salicylanilide I were tested for their toxicities against fathead minnows ( Pimephales promelas ) in the presence of Canadian waterweed ( Elodea canadensis ) or suspended clay. The plants had little effect on the activity of rotenone and antimycin but substantially reduced the activity of permethrin and pydrin (synthetic pyrethroids). Bentonite severely inhibited the activity of all chemicals tested. Salicylanilide I was affected least and pydrin most (27 times as much pydrin was required when I g/liter of bentonite was present in 96-hour tests). The efficacy of the registered fish toxicants rotenone and antimycin is probably not significantly affected by vegetation under field conditions, but is greatly reduced by suspended bentonite clay.

North American Journal of Fisheries Management↗
USGS1982

Feeding activity and spawning time of striped bass in the Colorado River Inlet, Lake Powell, Utah

Striped bass, Morone saxatilis , from Lake Powell, Utah spawned in or near the mixing zone of the reservoir and the Colorado River in 1980 and 1981. The fish did not move through Cataract Canyon rapids just above the reservoir in either year. Of 321 adult striped bass stomachs examined, 30% contained food and 28% contained threadfin shad, Dorosoma petenense. No stomachs contained native threatened or endangered Colorado River fishes.

Utah↗