Theodore Castro-Santos
Research Ecologist at the Eastern Ecological Science Center's S.O. Conte Research Laboratory in Turners Falls, MA
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
Professional Experience
US Geological Survey (1995-present)
U.S. Fish and Wildlife Service (1992-1995)
Education and Certifications
PhD Organismic and Evolutionary Biology; University of Massachusetts Amherst (2002)
MS Wildlife Biology Washington State University (1991)
BA Colgate University (1987)
Affiliations and Memberships*
American Fisheries Society
Society for Integrative and Comparative Biology
Science and Products
Filter Total Items: 80
The effects of horizontally and vertically oriented baffles on flow structure andascent performance of upstream-migrating fish The effects of horizontally and vertically oriented baffles on flow structure andascent performance of upstream-migrating fish
Considerable effort has been expended to construct culverts and fishways that allow for fish passage. However, the designs have seldom considered behaviour, energetics, and biomechanics of fish. In this study, we performed controlled experiments, in which upstreammigrating Alewife (Alosa pseudoharengus) and Brook Trout (Salvelinus fontinalis) were allowed to volitionally enter either one...
Authors
Eva Enders, Theodore Castro-Santos, Jay Lacey
Downstream migration and multiple dam passage by Atlantic Salmon smolts Downstream migration and multiple dam passage by Atlantic Salmon smolts
The purpose of this study was to investigate behavior and survival of radio-tagged wild and hatchery-reared landlocked Atlantic Salmon Salmo salar smolts as they migrated past three hydropower dams equipped with fish bypass solutions in the Winooski River, Vermont. Among hatchery-reared smolts, those released early were more likely to initiate migration and did so after less delay than...
Authors
D. Nyqvist, Stephen McCormick, L. Greenberg, W.R. Ardren, E. Bergman, O. Calles, Theodore Castro-Santos
Novel, continuous monitoring of fine‐scale movement using fixed‐position radiotelemetry arrays and random forest location fingerprinting Novel, continuous monitoring of fine‐scale movement using fixed‐position radiotelemetry arrays and random forest location fingerprinting
Radio‐tag signals from fixed‐position antennas are most often used to indicate presence or absence of individuals, or to estimate individual activity levels from signal strength variation within an antenna's detection zone. The potential of such systems to provide more precise information on tag location and movement has not been explored in great detail in an ecological setting.By...
Authors
Andrew Harbicht, Theodore Castro-Santos, William Ardren, Dimitry Gorsky, Dylan Fraser
Is motivation important to brook trout passage through culverts? Is motivation important to brook trout passage through culverts?
Culverts can restrict movement of stream-dwelling fish. Motivation to enter and ascend these structures is an essential precursor for successful passage. However, motivation is challenging to quantify. Here, we use attempt rate to assess motivation of 447 brook trout (Salvelinus fontinalis) entering three culverts under a range of hydraulic, environmental, and biological conditions. A...
Authors
Elsa Goerig, Theodore Castro-Santos
Migratory behavior of adult sea lamprey and cumulative passage performance through four fishways Migratory behavior of adult sea lamprey and cumulative passage performance through four fishways
This article describes a study of PIT-tagged sea lamprey (Petromyzon marinus) ascending four fishways comprising three designs at two dams on the Connecticut River, USA. Migration between dams was rapid (median migration rate = 23 km·day−1). Movement through the fishways was much slower, however (median = 0.02–0.33 km·day−1). Overall delay at dams was substantial (median = 13.6–14.6 days...
Authors
Theodore Castro-Santos, Xiaotao Shi, Alexander Haro
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’ 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’
Detailed re-examination of the datasets that were used for a meta-analysis of fishway attraction and passage revealed a number of errors that we addressed and corrected. We subsequently re-analysed the revised dataset, and results showed no significant changes in the primary conclusions of the original study; for most species, effective performance cannot be assured for any fishway type.
Authors
C.M. Bunt, Theodore Castro-Santos, Alexander Haro
Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam
Passage of fish through hydropower dams is associated with mortality, delay, increased energy expenditure and migratory failure for migrating fish and the need for remedial measures for both upstream and downstream migration is widely recognised. A functional fish passage must ensure safe and timely passage routes that a substantial portion of migrating fish will use. Passage solutions...
Authors
Daniel Nyqvist, L. Greenberg, E. Goerig, O. Calles, E. Bergman, William Ardren, Theodore Castro-Santos
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 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
Passage performance of brown trout (Salmo trutta), Iberian barbel (Luciobarbus bocagei), and northern straight-mouth nase (Pseudochondrostoma duriense) was investigated in a vertical slot fishway in the Porma River (Duero River basin, Spain) using PIT telemetry. We analysed the effects of different fishway discharges on motivation and passage success. Both cyprinid species ascended the...
Authors
Fco. Sanz-Ronda, F.J. Bravo-Cordoba, J.F. Fuentes-Perez, Theodore Castro-Santos
Analysis of brook trout spatial behavior during passage attempts in corrugated culverts using near-infrared illumination video imagery Analysis of brook trout spatial behavior during passage attempts in corrugated culverts using near-infrared illumination video imagery
We used video recording and near-infrared illumination to document the spatial behavior of brook trout of various sizes attempting to pass corrugated culverts under different hydraulic conditions. Semi-automated image analysis was used to digitize fish position at high temporal resolution inside the culvert, which allowed calculation of various spatial behavior metrics, including...
Authors
Normand Bergeron, Pierre-Marc Constantin, Elsa Goerig, Theodore Castro-Santos
Brook trout passage performance through culverts Brook trout passage performance through culverts
Culverts can restrict access to habitat for stream-dwelling fishes. We used passive integrated transponder telemetry to quantify passage performance of >1000 wild brook trout (Salvelinus fontinalis) attempting to pass 13 culverts in Quebec under a range of hydraulic and environmental conditions. Several variables influenced passage success, including complex interactions between...
Authors
Elsa Goerig, Theodore Castro-Santos, Normand Bergeron
Sprinting performance of two Iberian fish: Luciobarbus bocagei and Pseudochondrostoma duriense in an open channel flume Sprinting performance of two Iberian fish: Luciobarbus bocagei and Pseudochondrostoma duriense in an open channel flume
This paper presents sprinting data from Iberian barbel (Luciobarbus bocagei) and northern straight-mouth nase (Pseudochondrostoma duriense), volitionally swimming against high velocity flows (1.5, 2.5 and 3 m s−1) in an open channel flume. Swimming endurance and speed greatly exceeded previously published observations with both species attaining swim speeds >20 body lengths s−1. Flow...
Authors
Francisco Sanz-Ronda, Jorge Ruiz-Legazpi, Francisco Bravo-Cordoba, Sergio Makrakis, Theodore Castro-Santos
Accelerometer-derived activity correlates with volitional swimming speed in lake sturgeon (Acipenser fulvescens) Accelerometer-derived activity correlates with volitional swimming speed in lake sturgeon (Acipenser fulvescens)
Quantifying fine-scale locomotor behaviours associated with different activities is challenging for free-swimming fish.Biologging and biotelemetry tools can help address this problem. An open channel flume was used to generate volitionalswimming speed (Us) estimates of cultured lake sturgeon (Acipenser fulvescens Rafinesque, 1817) and these were paired withsimultaneously recorded...
Authors
J.D. Thiem, J.W. Dawson, A.C. Gleiss, E.G. Martins, Alexander Haro, Theodore Castro-Santos, A. J. Danylchuk, R. Wilson, S. Cooke
Science and Products
Filter Total Items: 80
The effects of horizontally and vertically oriented baffles on flow structure andascent performance of upstream-migrating fish The effects of horizontally and vertically oriented baffles on flow structure andascent performance of upstream-migrating fish
Considerable effort has been expended to construct culverts and fishways that allow for fish passage. However, the designs have seldom considered behaviour, energetics, and biomechanics of fish. In this study, we performed controlled experiments, in which upstreammigrating Alewife (Alosa pseudoharengus) and Brook Trout (Salvelinus fontinalis) were allowed to volitionally enter either one...
Authors
Eva Enders, Theodore Castro-Santos, Jay Lacey
Downstream migration and multiple dam passage by Atlantic Salmon smolts Downstream migration and multiple dam passage by Atlantic Salmon smolts
The purpose of this study was to investigate behavior and survival of radio-tagged wild and hatchery-reared landlocked Atlantic Salmon Salmo salar smolts as they migrated past three hydropower dams equipped with fish bypass solutions in the Winooski River, Vermont. Among hatchery-reared smolts, those released early were more likely to initiate migration and did so after less delay than...
Authors
D. Nyqvist, Stephen McCormick, L. Greenberg, W.R. Ardren, E. Bergman, O. Calles, Theodore Castro-Santos
Novel, continuous monitoring of fine‐scale movement using fixed‐position radiotelemetry arrays and random forest location fingerprinting Novel, continuous monitoring of fine‐scale movement using fixed‐position radiotelemetry arrays and random forest location fingerprinting
Radio‐tag signals from fixed‐position antennas are most often used to indicate presence or absence of individuals, or to estimate individual activity levels from signal strength variation within an antenna's detection zone. The potential of such systems to provide more precise information on tag location and movement has not been explored in great detail in an ecological setting.By...
Authors
Andrew Harbicht, Theodore Castro-Santos, William Ardren, Dimitry Gorsky, Dylan Fraser
Is motivation important to brook trout passage through culverts? Is motivation important to brook trout passage through culverts?
Culverts can restrict movement of stream-dwelling fish. Motivation to enter and ascend these structures is an essential precursor for successful passage. However, motivation is challenging to quantify. Here, we use attempt rate to assess motivation of 447 brook trout (Salvelinus fontinalis) entering three culverts under a range of hydraulic, environmental, and biological conditions. A...
Authors
Elsa Goerig, Theodore Castro-Santos
Migratory behavior of adult sea lamprey and cumulative passage performance through four fishways Migratory behavior of adult sea lamprey and cumulative passage performance through four fishways
This article describes a study of PIT-tagged sea lamprey (Petromyzon marinus) ascending four fishways comprising three designs at two dams on the Connecticut River, USA. Migration between dams was rapid (median migration rate = 23 km·day−1). Movement through the fishways was much slower, however (median = 0.02–0.33 km·day−1). Overall delay at dams was substantial (median = 13.6–14.6 days...
Authors
Theodore Castro-Santos, Xiaotao Shi, Alexander Haro
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’ 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’
Detailed re-examination of the datasets that were used for a meta-analysis of fishway attraction and passage revealed a number of errors that we addressed and corrected. We subsequently re-analysed the revised dataset, and results showed no significant changes in the primary conclusions of the original study; for most species, effective performance cannot be assured for any fishway type.
Authors
C.M. Bunt, Theodore Castro-Santos, Alexander Haro
Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam Migratory delay leads to reduced passage success of Atlantic salmon smolts at a hydroelectric dam
Passage of fish through hydropower dams is associated with mortality, delay, increased energy expenditure and migratory failure for migrating fish and the need for remedial measures for both upstream and downstream migration is widely recognised. A functional fish passage must ensure safe and timely passage routes that a substantial portion of migrating fish will use. Passage solutions...
Authors
Daniel Nyqvist, L. Greenberg, E. Goerig, O. Calles, E. Bergman, William Ardren, Theodore Castro-Santos
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 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
Passage performance of brown trout (Salmo trutta), Iberian barbel (Luciobarbus bocagei), and northern straight-mouth nase (Pseudochondrostoma duriense) was investigated in a vertical slot fishway in the Porma River (Duero River basin, Spain) using PIT telemetry. We analysed the effects of different fishway discharges on motivation and passage success. Both cyprinid species ascended the...
Authors
Fco. Sanz-Ronda, F.J. Bravo-Cordoba, J.F. Fuentes-Perez, Theodore Castro-Santos
Analysis of brook trout spatial behavior during passage attempts in corrugated culverts using near-infrared illumination video imagery Analysis of brook trout spatial behavior during passage attempts in corrugated culverts using near-infrared illumination video imagery
We used video recording and near-infrared illumination to document the spatial behavior of brook trout of various sizes attempting to pass corrugated culverts under different hydraulic conditions. Semi-automated image analysis was used to digitize fish position at high temporal resolution inside the culvert, which allowed calculation of various spatial behavior metrics, including...
Authors
Normand Bergeron, Pierre-Marc Constantin, Elsa Goerig, Theodore Castro-Santos
Brook trout passage performance through culverts Brook trout passage performance through culverts
Culverts can restrict access to habitat for stream-dwelling fishes. We used passive integrated transponder telemetry to quantify passage performance of >1000 wild brook trout (Salvelinus fontinalis) attempting to pass 13 culverts in Quebec under a range of hydraulic and environmental conditions. Several variables influenced passage success, including complex interactions between...
Authors
Elsa Goerig, Theodore Castro-Santos, Normand Bergeron
Sprinting performance of two Iberian fish: Luciobarbus bocagei and Pseudochondrostoma duriense in an open channel flume Sprinting performance of two Iberian fish: Luciobarbus bocagei and Pseudochondrostoma duriense in an open channel flume
This paper presents sprinting data from Iberian barbel (Luciobarbus bocagei) and northern straight-mouth nase (Pseudochondrostoma duriense), volitionally swimming against high velocity flows (1.5, 2.5 and 3 m s−1) in an open channel flume. Swimming endurance and speed greatly exceeded previously published observations with both species attaining swim speeds >20 body lengths s−1. Flow...
Authors
Francisco Sanz-Ronda, Jorge Ruiz-Legazpi, Francisco Bravo-Cordoba, Sergio Makrakis, Theodore Castro-Santos
Accelerometer-derived activity correlates with volitional swimming speed in lake sturgeon (Acipenser fulvescens) Accelerometer-derived activity correlates with volitional swimming speed in lake sturgeon (Acipenser fulvescens)
Quantifying fine-scale locomotor behaviours associated with different activities is challenging for free-swimming fish.Biologging and biotelemetry tools can help address this problem. An open channel flume was used to generate volitionalswimming speed (Us) estimates of cultured lake sturgeon (Acipenser fulvescens Rafinesque, 1817) and these were paired withsimultaneously recorded...
Authors
J.D. Thiem, J.W. Dawson, A.C. Gleiss, E.G. Martins, Alexander Haro, Theodore Castro-Santos, A. J. Danylchuk, R. Wilson, S. Cooke
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government