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USGS2021

Imaging the next Cascadia earthquake: Optimal design for a seafloor GNSS- A network

The Cascadia subduction zone in the Pacific Northwest of the United States of America capable of producing magnitude ∼9 earthquakes, likely often accompanied by tsunamis. An outstanding question in this region is the degree and spatial extent of interseismic strain accumulation on the subduction megathrust. Seafloor geodetic methods combining GNSS and underwater acoustic ranging (GNSS-A) are capable of imaging this strain accumulation on the offshore portion of the subduction zone and therefore anticipating the potential size and rupture pattern of a future earthquake. However, the high cost of seafloor geodesy means that only a limited number of stations may be deployed and monitored. To facilitate expansion of current geodetic networks offshore, we develop a quantitative recommendation of optimal locations for future seafloor geodetic observations, based on the amount of new information provided by that observation. The optimal network depends on the problem that one is trying to solve with those observations (mapping subduction locking rates, coupling rates, constraining total moment rate, etc.), and on a number of modelling and data uncertainty assumptions. In particular, data uncertainty assumptions will change over time, as more position observations reduce velocity uncertainties. We find that near-trench observations on the megathrust hangingwall, distributed along-strike, consistently provide significant reduction in differential entropy over a large suite of assumptions, and that a well-placed seafloor observation can provide up to ∼30 times the information gain of the most optimal onshore observation.

British Columbia, California, Oregon, Washington↗

USGS2015

A comparison of methods to estimate seismic phase delays--Numerical examples for coda wave interferometry

Time-shift estimation between arrivals in two seismic traces before and after a velocity perturbation is a crucial step in many seismic methods. The accuracy of the estimated velocity perturbation location and amplitude depend on this time shift. Windowed cross correlation and trace stretching are two techniques commonly used to estimate local time shifts in seismic signals. In the work presented here, we implement Dynamic Time Warping (DTW) to estimate the warping function – a vector of local time shifts that globally minimizes the misfit between two seismic traces. We illustrate the differences of all three methods compared to one another using acoustic numerical experiments. We show that DTW is comparable to or better than the other two methods when the velocity perturbation is homogeneous and the signal-to-noise ratio is high. When the signal-to-noise ratio is low, we find that DTW and windowed cross correlation are more accurate than the stretching method. Finally, we show that the DTW algorithm has better time resolution when identifying small differences in the seismic traces for a model with an isolated velocity perturbation. These results impact current methods that utilize not only time shifts between (multiply) scattered waves, but also amplitude and decoherence measurements. DTW is a new tool that may find new applications in seismology and other geophysical methods (e.g., as a waveform inversion misfit function).

Geophysical Journal International↗

USGS1989

Seasonal and annual variation in the diet of Atlantic cod ( Gadus morhua ) in relation to the abundance of capelin ( Mallotus villosus ) off eastern Newfoundland, Canada

The importance of capelin as prey for cod has long been known (Thompson, 1943; and see Lilly (1987) for a review); however, no studies have been conducted on how the highly dynamic seasonal and yearly variations in capelin abundance affect cod diet. We studied the occurrence of capelin in cod stomachs in relation to the relative abundance of capelin at Witless Bay, Newfoundland (47°15’N 52°46’W), during June, July and August, 1982-1984. The mean number of capelin per stomach and the per cent occurrence of stomachs containing capelin were determined for each collection of stomachs. A total of 680 stomachs were examined. Cod were sampled from those caught in gillnets by fishermen and averaged 66 cm ± 8 (s.d.) in 1983 and 62 cm ± 8 (s.d.) in 1984. Relative abundance of capelin in the local habitat was determined by conducting hydroacoustic surveys around Gull Island in Witless Bay, the same area where cod were collected for stomach content analysis. Only hydroacoustic surveys conducted within three days of cod stomach collections were analyzed. Further details of hydroacoustic surveys including quantifications of acoustic echograms are described in Piatt (1989).

Newfoundland↗

USGS2015

Foraging range movements of the endangered Hawaiian hoary bat, Lasiurus cinereus semotus (Chiroptera: Vespertilionidae)

We documented nightly movements of Hawaiian hoary bats ( Lasiurus cinereus semotus ) on the island of Hawai’i. Based on data from 28 radiotagged individuals mean foraging range (FR) was 230.7±72.3 ha, core-use area (CUA) was 25.5±6.9 ha (or 11.1% of mean FR), and the mean long axis (LAX) across the FR was 3,390.8±754.3 m. There was almost no overlap in CUAs among 4 adult males having overlapping foraging areas and tracked simultaneously or within a 90-day window of each other. CUAs of subadults partially overlapped with multiple adult males or with one other subadult. High variance in FRs, cores use areas, and LAX across the FR perhaps reflect localized stochastic variables such as weather, habitat, and food resources. Hawaiian hoary bats use moderately large FRs among insectivorous bats studied with comparable methodologies; however, foraging activity indicated by documentation of acoustic feeding buzzes is concentrated within one or a few disjunct areas cumulatively forming the 50% fixed kernel of CUA. The concentration of feeding activity, low values of individual overlap, and agonistic chasing behavior within CUAs all demonstrate a structured use of individual space by Hawaiian hoary bats.

Hawaii↗

USGS2025

Tailwater residency patterns of Silver Carp at Kentucky Lock and Dam

Objective The management of invasive Silver Carp Hypophthalmichthys molitrix in the Tennessee River basin focuses on removal, and there is interest in extending removal efforts to the tailwater environments of high-head locks and dams along the Tennessee River, such as Kentucky Dam. We used acoustic telemetry data from Silver Carp to understand important ecological associations underlying their residence in the Kentucky Dam tailwater, measured by daily fish counts and mean residence time. Methods We used time-series-informed regression models, variance partitioning, and cross-correlation function analysis to associate six predictors, including lock and dam operations (total, spill gate, and turbine discharge and number of lockages), hydrology (tailwater elevation), and water temperature, with two measures of Silver Carp residency (daily counts and mean residence time). Results We found that spill-induced hydrology (total discharge + spill discharge + tailwater elevation) was negatively associated with daily counts but not with residence time, whereas temperature was positively associated with counts and negatively associated with residence times. Variance partitioning indicated that nearly all the variance in counts and residence times was jointly explained by temporal effects, lock and dam operations (discharge, tailwater elevation, and lockages), and temperature. The cross-correlations indicated that the counts were lagged by all predictors, sometimes up to 5 d, whereas residence times were lagged by both total and spill discharge and number of lockages. Conclusions We found that discharge and water temperature were principally associated with residency of Silver Carp in the Kentucky Dam tailwater. However, these associations were entirely temporally constrained, which can affect how strongly and how quickly Silver Carp respond to changing environmental conditions across different time scales. Managers can leverage these associations to plan removal periods where daily tailwater conditions/dam operations are favorable to invasive carp residence (e.g., >10°C and <2,500 m 3 /s) and adjust fishing effort to optimize removal rates in response to changing conditions.

Kentucky Lock and Dam↗

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

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↗

USGS2026

Response of juvenile Chinook Salmon to an experimental reservoir operation to facilitate downstream migration

Objectives High-head dams and storage reservoirs impact ecological processes, impeding recovery efforts of Pacific salmon Oncorhynchus spp. in the western United States. These projects can delay migration, increase risks of predation and disease, and induce mortality for juvenile Pacific salmon during downstream passage. To mitigate these negative effects, large-scale changes to dam operations have been proposed as interim measures or alternatives to engineered fish passage solutions. A novel deep drawdown operation of the Lookout Point Project (two dams and reservoirs) in Oregon serves as a case study for learning from a large-scale management experiment. Beginning in July 2024, Lookout Point Reservoir was slowly lowered to attain minimal levels from mid-November to mid-December with the intent of expediting downstream passage through the project for juvenile Chinook Salmon Oncorhynchus tshawytscha . We evaluated the impacts of the months-long operation on two life histories of juvenile Chinook Salmon with different rearing environments and growth rates. Methods Acoustic telemetry was used to monitor juvenile Chinook Salmon in the Lookout Point Project. Environmental data, including water temperature and hydrological conditions, were collected. We fitted a time-integrated migration survival model to these data to estimate the effects of management-influenced covariates and fish length on apparent survival and residence time in each reach of the Lookout Point Project. Results Larger fish had higher survival than smaller fish in each reach of the Lookout Point Project. Apparent survival through each dam of the Lookout Point Project was highest and forebay residence times lowest during the latter part of the drawdown (late November). However, early periods of the drawdown (September) were associated with a transition from a thermally stratified reservoir to a warm isothermal reservoir that negatively impacted reservoir survival. Conclusions The deep drawdown of the Lookout Point Project achieved the management intent to improve downstream passage for juvenile Chinook Salmon at the lowest reservoir elevations but also caused unintended changes in the reservoir rearing environment prior to full drawdown. Further research could resolve remaining uncertainties regarding the overall effectiveness of drawdown operations with respect to the population dynamics of different juvenile life history strategies. Understanding these factors would help optimize future management actions aimed at Pacific salmon recovery above the Lookout Point Project.

Oregon↗

USGS2025

Reconstructing relative abundance indices for Atlantic sturgeon using hierarchical ecological models

Objective The Atlantic Sturgeon Acipenser oxyrinchus is a wide-ranging, long-lived diadromous fish that is endangered in most of its range. Our objective was to develop and apply long-term, detection-corrected indices of relative abundance for juvenile and adult Atlantic Sturgeon in the Hudson River, New York, United States, to support population monitoring and stock assessment. Methods We used long-term gill-net catches to estimate relative abundances of juvenile and adult Atlantic Sturgeon while accounting for imperfect detection within an N- mixture modeling framework. We validated the model framework using a simulation–estimation framework based on mean parameter estimates from the adult Atlantic Sturgeon relative abundance index. Results Simulation testing indicated that absolute abundance estimates may be biased low due to poor characterization of detection probabilities. However, model estimates of relative abundance tracked simulated abundance trends well. Juvenile relative abundance estimates followed similar trends as raw gill-net catches but were less variable among years when corrected for detection probability. Relative abundance of juveniles increased from 2004 to 2015 prior to declining through 2022, with little evidence for change between the start and end of the survey. Detection-corrected indices for adult sturgeon indicated a consistent increase in relative abundance that was not readily apparent in raw catch indices. Conclusions Detection-corrected catch indices can provide improved characterization of Atlantic Sturgeon relative abundance dynamics over raw gill-net catches through use of N- mixture models. The approach has broad applicability to data types that are commonly collected for understanding population trends in stock assessment. Estimation of absolute abundance and other population demographics germane to management would benefit from alternative or auxiliary data collected through approaches such as side-scan sonar or acoustic telemetry, which are increasingly common for monitoring sturgeon populations.

New York↗

USGS2010

Global positioning system and associated technologies in animal behaviour and ecological research

Biologists can equip animals with global positioning system (GPS) technology to obtain accurate (less than or equal to 30 m) locations that can be combined with sensor data to study animal behaviour and ecology. We provide the background of GPS techniques that have been used to gather data for wildlife studies. We review how GPS has been integrated into functional systems with data storage, data transfer, power supplies, packaging and sensor technologies to collect temperature, activity, proximity and mortality data from terrestrial species and birds. GPS 'rapid fixing' technologies combined with sensors provide location, dive frequency and duration profiles, and underwater acoustic information for the study of marine species. We examine how these rapid fixing technologies may be applied to terrestrial and avian applications. We discuss positional data quality and the capability for high-frequency sampling associated with GPS locations. We present alternatives for storing and retrieving data by using dataloggers (biologging), radio-frequency download systems (e.g. very high frequency, spread spectrum), integration of GPS with other satellite systems (e.g. Argos, Globalstar) and potential new data recovery technologies (e.g. network nodes). GPS is one component among many rapidly evolving technologies. Therefore, we recommend that users and suppliers interact to ensure the availability of appropriate equipment to meet animal research objectives.

Philosophical Transactions of the Royal Society B:↗

USGS1996

Vertical spatial coherence model for a transient signal forward-scattered from the sea surface

The treatment of acoustic energy forward scattered from the sea surface, which is modeled as a random communications scatter channel, is the basis for developing an expression for the time-dependent coherence function across a vertical receiving array. The derivation of this model uses linear filter theory applied to the Fresnel-corrected Kirchhoff approximation in obtaining an equation for the covariance function for the forward-scattered problem. The resulting formulation is used to study the dependence of the covariance on experimental and environmental factors. The modeled coherence functions are then formed for various geometrical and environmental parameters and compared to experimental data.

IEEE Journal of Oceanic Engineering↗

USGS2018

A distributed pipeline for DIDSON data processing

Technological advances in the field of ecology allow data on ecological systems to be collected at high resolution, both temporally and spatially. Devices such as Dual-frequency Identification Sonar (DIDSON) can be deployed in aquatic environments for extended periods and easily generate several terabytes of underwater surveillance data which may need to be processed multiple times. Due to the large amount of data generated and need for flexibility in processing, a distributed pipeline was constructed for DIDSON data making use of the Hadoop ecosystem. The pipeline is capable of ingesting raw DIDSON data, transforming the acoustic data to images, filtering the images, detecting and extracting motion, and generating feature data for machine learning and classification. All of the tasks in the pipeline can be run in parallel and the framework allows for custom processing. Applications of the pipeline include monitoring migration times, determining the presence of a particular species, estimating population size and other fishery management tasks.

Conference Paper↗

USGS2008

Measuring gravity currents in the Chicago River, Chicago, Illinois

Recent studies of the Chicago River have determined that gravity currents are responsible for persistent bidirectional flows that have been observed in the river. A gravity current is the flow of one fluid within another caused by a density difference between the fluids. These studies demonstrated how acoustic Doppler current profilers (ADCP) can be used to detect and characterize gravity currents in the field. In order to better understand the formation and evolution of these gravity currents, the U.S. Geological Survey (USGS) has installed ADCPs and other instruments to continuously measure gravity currents in the Chicago River and the North Branch Chicago River. These instruments include stage sensors, thermistor strings, and both upward-looking and horizontal ADCPs. Data loggers and computers installed at gaging stations along the river are used to collect data from these instruments and transmit them to USGS offices. ?? 2008 IEEE.

Illinois↗

USGS2011

2-D inner-shelf current observations from a single VHF WEllen RAdar (WERA) station

The majority of High Frequency (HF) radars used worldwide operate at medium to high frequencies (8 to 30 MHz) providing spatial resolutions ranging from 3 to 1.5 km and ranges from 150 to 50 km. This paper presents results from the deployment of a single Very High Frequency (VHF, 48 MHz) WEllen RAdar (WERA) radar with spatial resolution of 150 m and range 10-15 km, used in the nearshore off Cape Hatteras, NC, USA. It consisted of a linear array of 12 antennas operating in beam forming mode. Radial velocities were estimated from radar backscatter for a variety of wind and nearshore wave conditions. A methodology similar to that used for converting acoustically derived beam velocities to an orthogonal system is presented for obtaining 2-D current fields from a single station. The accuracy of the VHF radar-derived radial velocities is examined using a new statistical technique that evaluates the system over the range of measured velocities. The VHF radar velocities showed a bias of 3 to 7 cm/s over the experimental period explainable by the differences in radar penetration and in-situ measurement height. The 2-D current field shows good agreement with the in-situ measurements. Deviations and inaccuracies are well explained by the geometric dilution analysis.

North Carolina↗

USGS2015

Velocity bias induced by flow patterns around ADCPs and associated deployment platforms

Velocity measurements near the Acoustic Doppler Current Profiler (ADCP) are important for mapping surface currents, measuring velocity and discharge in shallow streams, and providing accurate estimates of discharge in the top unmeasured portion of the water column. Improvements to ADCP performance permit measurement of velocities much closer (5 cm) to the transducer than has been possible in the past (25 cm). Velocity profiles collected by the U.S. Geological Survey (USGS) with a 1200 kHz Rio Grande Zedhead ADCP in 2002 showed a negative bias in measured velocities near the transducers. On the basis of these results, the USGS initiated a study combining field, laboratory, and numerical modeling data to assess the effect of flow patterns caused by flow around the ADCP and deployment platforms on velocities measured near the transducers. This ongoing study has shown that the negative bias observed in the field is due to the flow pattern around the ADCP. The flow pattern around an ADCP violates the basic assumption of flow homogeneity required for an accurate three-dimensional velocity solution. Results, to date (2014), have indicated velocity biases within the measurable profile, due to flow disturbance, for the TRDI 1200 kHz Rio Grande Zedhead and the SonTek RiverSurveyor M9 ADCPs. The flow speed past the ADCP, the mount and the deployment platform have also been shown to play an important role in the magnitude and extent of the velocity bias.

Conference Paper↗

USGS2015

Workgroup for Hydraulic laboratory Testing and Verification of Hydroacoustic Instrumentation

An international workgroup was recently formed for hydraulic laboratory testing and verification of hydroacoustic instrumentation used for water velocity measurements. The activities of the workgroup have included one face to face meeting, conference calls and an inter-laboratory exchange of two acoustic meters among participating laboratories. Good agreement was found among four laboratories at higher tow speeds and poorer agreement at the lowest tow speed.

Conference Paper↗

USGS2002

Porometric properties of siliciclastic marine sand: A comparison of traditional laboratory measurements with image analysis and effective medium modeling

During the 1999 sediment acoustics experiment (SAX99), porometric properties were measured and predicted for a well sorted, medium sand using standard laboratory geotechnical methods and image analysis of resin-impregnated sediments. Sediment porosity measured by laboratory water-weight-loss methods (0.372 ?? 0.0073 for mean ??1 standard deviation) is 0.026 lower than determined by microscopic image analysis of resin-impregnated sediments (0.398 ?? 0.029). Values of intrinsic permeability (m2) determined from constant-head permeameter measurements (3.29 ?? 10-11 ?? 0.60 ?? 10-11) and by microscopic image analysis coupled with effective medium theory modeling (2.78 ?? 10-11 ?? 1.01 ?? 10-11) are nearly identical within measurement error. The mean value of tortuosity factor measured from images is 1.49 ?? 0.09, which is in agreement with tortuosity factor determined from electrical resistivity measurements. Slight heterogeneity and anisotropy are apparent in the top three centimeters of sediment as determined by image-based porometric property measurements. However, the overall similarity for both measured and predicted values of porosity and permeability among and within SAX99 sites indicates sediments are primarily homogeneous and isotropic and pore size distributions are fairly uniform. The results indicate that an effective medium theory technique and two-dimensional image analysis accurately predicts bulk permeability in resin-impregnated sands.

IEEE Journal of Oceanic Engineering↗