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Theodore R Castro-Santos

Ted is a Research Ecologist Eastern Ecological Science Center in Kearneysville, WV.

Human activities have caused extensive fragmentation of riverine corridors.  Dams, culverts, and other barriers prevent migratory and riverine fishes from accessing key habitats.  This is particularly problematic for diadromous fishes like Atlantic salmon and American shad that must transition between fresh- and saltwater habitats in order to complete their life cycles.  Swimming performance and behavioral responses to hydraulic conditions (turbulence, velocity, etc.) are major interests, as is development of quantitative methods for identifying and characterizing barriers.  This work has broad relevance, not only to stewardship and management of aquatic resources, but also to understanding fundamental aspects of the ecology and evolution of fishes. Some current projects include:

  • Sprint-swimming performance of migratory and riverine species
  • Effects of turbulence on swimming performance, biomechanics, and behavior
  • Modeling fish passage through culverts
  • Bioenergetics models of anadromous fish migration

Science and Products

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USGS science for a changing world logo

A generic web application to visualize and understand movements of tagged animals

The goal of this project was to maximize the value of expensive animal tagging data. We developed an interactive web application to help scientists understand patterns in their own tagging datasets and to help scientists, funders and agencies communicate tagging data to decision-makers and to the general public. Interactive visualizations have emerged recently as a valuable tool for identifying pa
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Community for Data Integration (CDI)
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A generic web application to visualize and understand movements of tagged animals

The goal of this project was to maximize the value of expensive animal tagging data. We developed an interactive web application to help scientists understand patterns in their own tagging datasets and to help scientists, funders and agencies communicate tagging data to decision-makers and to the general public. Interactive visualizations have emerged recently as a valuable tool for identifying pa
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Sea lamprey

Fish locomotion and biomechanics as limiting and optimizing factors in fish passage

Swimming ability determines how well fish are able to access habitat, and is a fundamental design consideration for passing fish at dams, road crossings, etc.
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Ecosystems, Energy and Minerals, Water Resources, Environmental Health Program, Species Management Research Program, Eastern Ecological Science Center
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Fish locomotion and biomechanics as limiting and optimizing factors in fish passage

Swimming ability determines how well fish are able to access habitat, and is a fundamental design consideration for passing fish at dams, road crossings, etc.
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aquatic biomechanics

Fish Biomechanics

Biomechanics is the study of mechanical laws relating to the movement of living organisms.
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Ecosystems, Species Management Research Program, Eastern Ecological Science Center
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Fish Biomechanics

Biomechanics is the study of mechanical laws relating to the movement of living organisms.
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Herring passage at Herring River Tidegates

Data used to produce results for publication in Canadian Journal of Fisheries and Aquatic Sciences
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Eastern Ecological Science Center
Filter Total Items: 38

Applied aspects of locomotion and biomechanics

Locomotion is the act and process of moving from place to place, which is fundamental to the life history of all mobile organisms. While the field of biomechanics encompasses the study of the physical constraints of what animals are capable of, ecological contexts require an integrated view that includes ecology and behavior. This chapter provides an overview of some of the areas where locomotion

Fish-inspired segment models for undulatory swimming

Many aquatic animals swim by undulatory body movements and understanding the diversity of these movements could unlock the potential for designing better underwater robots. Here, we analyzed the steady swimming kinematics of a diverse group of fish species to investigate whether their undulatory movements can be represented using a series of interconnected multi-segment models, and if so, to ident

BIOTAS: BIOTelemetry Analysis Software, for the semi-automated removal of false positives from radio telemetry data

IntroductionRadio telemetry, one of the most widely used techniques for tracking wildlife and fisheries populations, has a false-positive problem. Bias from false-positive detections can affect many important derived metrics, such as home range estimation, site occupation, survival, and migration timing. False-positive removal processes have relied upon simple filters and personal opinion. To over

Convergence of undulatory swimming kinematics across a diversity of fishes

Fishes exhibit an astounding diversity of locomotor behaviors from classic swimming with their body and fins to jumping, flying, walking, and burrowing. Fishes that use their body and caudal fin (BCF) during undulatory swimming have been traditionally divided into modes based on the length of the propulsive body wave and the ratio of head:tail oscillation amplitude: anguilliform, subcarangiform, c
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Ecosystems, Eastern Ecological Science Center

Culverts delay upstream and downstream migrations of river herring (Alosa spp.)

Alewife (Alosa pseudoharengus) and blueback herring (Alosa aestivalis) are iteroparous anadromous fish found throughout the East Coast of North America. The phenology of anadromous fish migrations is important for fitness, and the duration of spawning migrations has been compressed in recent years in response to climate change. Anthropogenic barriers to movement, such as dams and culverts at road-
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Ecosystems, Eastern Ecological Science Center

Surface water with more natural temperatures promotes physiological and endocrine changes in landlocked Atlantic salmon smolts

Hatchery salmonid smolts are often reared using groundwater with elevated temperatures to maximize growth. Previous work has shown that rearing hatchery smolts in surface water with a more natural thermal regime resulted in increased return rates of adult landlocked Atlantic salmon (Salmo salar). We evaluated whether landlocked Atlantic salmon reared in surface water with a natural temperature reg
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Ecosystems, Eastern Ecological Science Center

Activity patterns of anadromous fish below a tide gate: Observations from high‐resolution imaging sonar

The construction of dams and tide gates on waterways has altered the physical structure of many coastal, estuarine, and freshwater systems. These changes have come at a cost to fish populations, most notably diadromous species, which rely on connectivity between marine and freshwater systems. These anthropogenic structures can have direct effects on migrating fish, such as blocking fish passage, o
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Ecosystems, Eastern Ecological Science Center

Tide gates form physical and ecological obstacles to river herring (Alosa spp.) spawning migrations

River herring (Alosa spp.) are anadromous fish that enter North American Atlantic coastal rivers and lakes each spring to spawn. Anthropogenic structures such as dams and tide gates serve as physical obstacles that limit river herring access to spawning habitat. This study examined the physical and ecological components affecting herring passage through a tide gate by applying a time-to-event anal

Wait and snap: eastern snapping turtles (Chelydra serpentina) prey on migratory fish at road-stream crossing culverts

There is growing evidence that culverts at road-stream crossings can increase fish density by reducing stream width and fish movement rates, making these passageways ideal predator ambush locations. In this study, we used a combination of videography and δ13C stable isotope analyses to investigate predator–prey interactions at a road-stream crossing culvert. Eastern snapping turtles (Chelydra serp

Effects of plunge pool configuration on downstream passage survival of juvenile blueback herring

Anadromous alosines are widespread throughout the Northern Hemisphere. Juveniles of this clade are notoriously fragile animals that are at high risk of injury and death associated with passage at hydroelectric facilities. Although turbine mortality is a common concern, conditions encountered when bypassed around these routes may also be hazardous. Downstream bypass structures typically discharge i
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Ecosystems, Eastern Ecological Science Center

How lipid content and temperature affect American shad (Alosa sapidissima) attempt rate and sprint swimming: Implications for overcoming migration barriers

How seasonal effects such as temperature increases and reduced lipid content affect the ability of anadromous fishes to traverse high-velocity barriers and sprint swimming is poorly understood. We evaluated American shad (Alosa sapidissima) swimming performance in a flume against high flow velocities (2.5–3.7 m·s−1) during the upstream migration period (April–May; temperatures 11.1–21.4 °C) to det
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Ecosystems, Eastern Ecological Science Center

Assessing risks from harbor dredging to the northernmost population of diamondback terrapins using acoustic telemetry

The northern diamondback terrapin (Malaclemys terrapin terrapin) is a saltmarsh-dependent turtle that occupies coastal habitats throughout much of the Atlantic coast of North America. We used a novel application of acoustic telemetry to quantify both mobility and occupancy of terrapins within a dredged harbor and surrounding habitats, and used these metrics to quantify relative risk to individuals
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Ecosystems, Eastern Ecological Science Center

Non-USGS Publications**

Bunt, C.M., Castro-Santos, T., Haro, A. Reinforcement and Validation of the Analyses and Conclusions Related to Fishway Evaluation Data from Bunt et al.: ‘Performance of Fish Passage Structures at Upstream Barriers to Migration (2016) River Research and Applications, 32 (10), pp. 2125-2137.
Sanz-Ronda, F.J., Bravo-Córdoba, F.J., Fuentes-Pérez, J.F., Castro-Santos, T. Ascent ability of brown trout, Salmo trutta, and two Iberian cyprinids - Iberian barbel, Luciobarbus bocagei, and northern straight-mouth nase, Pseudochondrostoma duriense - In a vertical slot fishway (2016) Knowledge and Management of Aquatic Ecosystems, 2016-January (417),
Sanz-Ronda, F.J., Ruiz-Legazpi, J., Bravo-Córdoba, F.J., Makrakis, S., Castro-Santos, T. Sprinting performance of two Iberian fish: Luciobarbus bocagei and Pseudochondrostoma duriense in an open channel flume (2015) Ecological Engineering, 83, pp. 61-70.
Goerig, E., Castro-Santos, T., Bergeron, N.É. Brook trout passage performance through culverts (2015) Canadian Journal of Fisheries and Aquatic Sciences, 73 (1), pp. 94-104.
Thiem, J.D., Dawson, J.W., Gleiss, A.C., Martins, E.G., Haro, A., Castro-Santos, T., Danylchuk, A.J., Wilson, R.P., Cooke, S.J. Accelerometer-derived activity correlates with volitional swimming speed in lake sturgeon (Acipenser fulvescens) (2015) Canadian Journal of Zoology, 93 (8), pp. 645-654.

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

One USGS scientist holds an adult brown trout in a water bath as a second USGS scientist inserts a radio tag.
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ABiKiS viewed from upstream
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Hydraulic jump
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Sea lamprey
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