Assistant Unit Leader - Florida Cooperative Fish and Wildlife Research Unit
Research Interests
Dr. Carthy's research centers on ecology of endangered species. His research interests involve reproductive ecology and physiology of coastal and wetland herpetofauna, with current focus on marine and freshwater turtles. He is also involved in research on threatened upland species and in conservation management oriented studies.
Teaching Interests
In addition to teaching herpetology classes centered on ecology and conservation of marine chelonids, Dr. Carthy has taught courses on bioethics and critical thinking. he is currently developing a graduate level course on coastal ecology.
Professional Experience
Assistant Unit Leader, Florida Cooperative Fish and Wildlife Research Unit, 1996-
Education and Certifications
Ph D University of Florida 1996
MS Slippery Rock University 1983
BS Manhattan College 1980
Science and Products
Filter Total Items: 51
Gopherus polyphemus (Gopher Tortoise) adult mortality
Gopherus polyphemus has typically high adult survivorship, with some populations reaching a mean annual survivorship of 93.4% (Howell et al. 2019. J. Wildl. Manage. 84:56–65). Instances of adult mortality are not commonly reported outside of large mortality events, and most often result from disease, starvation, dehydration, or chronic stress (Gates et al. 2002. Florida Sci. 65:185–
197; Cozad et
Genetic diversity of immature Kemp's ridley (Lepidochelys kempii) sea turtles from the northern Gulf of Mexico
The Kemp’s ridley (Lepidochelys kempii) is the world’s most endangered sea turtle species. Predominately nesting at only one beach in Mexico, this species declined to an estimated 300 females in the mid-1980s. Conservation efforts in the United States and Mexico, including a head start programme in southern Texas in which hatchlings were reared in captivity for several months before being released
Identification of the Gulf of Mexico as an important high-use habitat for leatherback turtles from Central America
Endangered leatherback sea turtles (Dermochelys coriacea) are wide-ranging, long-distance migrants whose movements are often associated with environmental cues. We examined the spatial distribution and habitat use for 33 satellite-tracked leatherbacks from nesting beaches on the Caribbean coast of Costa Rica and Panama from 2004 to 2018, an important nesting population for the leatherback Northwes
Using growth rates to estimate the minimum age and size at sexual maturity in a captive population of the critically endangered Central American river turtle Dermatemys mawii
The Central American river turtle Dermatemys mawii is a critically endangered species that has incurred substantial losses over the last several decades due to overhunting. This species is now being considered for head-starting programs (i.e. captive breeding of turtles for wild release). However, relatively little is known about their life history characteristics, especially with respect to growt
Using systems thinking to inform management of imperiled species: A case study with sea turtles
Management of imperiled species facing spatiotemporally dynamic threats is difficult. Systems thinking can inform their management by quantifying the impacts that they face. We apply systems thinking to the Northern Gulf of Mexico (NGM) loggerhead (Caretta caretta) Recovery Unit (RU), one of the smallest subpopulations of loggerheads nesting in the USA. We characterized disturbances to nests, mana
Environmental factors predicting the orientation of sea turtle hatchlings on a naturally lighted beach: A baseline for light-management goals
On sea turtle nesting beaches, artificial lighting associated with human development interferes with hatchling orientation from nest to sea. Although hatchling disorientation has been documented for many beaches, data that managers can use in understanding, predicting, and managing the issue are of limited detail. The present study provides baseline hatchling orientation data that can be compared
Tropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures
Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward‐moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold‐sensitive tropical organisms, sometimes at the expense of temperate organisms. Althoug
Home ranges and movements of two diamondback terrapins (Malaclemys terrapin macrospilota) in northwest Florida
The diamondback terrapin (Malaclemys terrapin) is a small estuarine turtle distributed along the Atlantic and Gulf Coasts of the USA that is threatened by drowning in crab pots, road mortality, exploitation in the pet trade, and habitat loss. Little is known about the movement patterns and home ranges of these turtles, particularly along the U.S. Gulf of Mexico coast. Satellite tags were deployed
Use of remote sensing tools to predict focal areas for sea turtle conservation in the Southwestern Atlantic
Fisheries bycatch of non-target species in the commercial fleet is a major source of anthropogenic injury and mortality for sea turtles and marine megafauna.The Río de la Plata maritime front (RLPMF) and its adjacent international waters – comprising part of the Argentine and Uruguayan exclusive economic zones, is a highly important fishing ground in the south-western Atlantic Ocean as well as fee
Predicting multi-species foraging hotspots for marine turtles in the Gulf of Mexico
Quantifying the distribution of animals and identifying underlying characteristics that define suitable habitat are essential for effective conservation of free-ranging species. Prioritizing areas for conservation is important in managing a geographic extent that has a high level of disturbance and limited conservation resources. We examined the potential use of a species distribution model ensemb
Growth rates for immature Kemp’s ridley sea turtles from a foraging area in the northern Gulf of Mexico
Examining vital rates helps clarify how environmental characteristics, biological resources and human activities affect population growth. Carapace lengths were gathered for 241 Kemp’s ridley Lepidochelys kempii sea turtles that were marked and recaptured (n = 23) between 2011 and 2019 at a foraging location in northwest Florida, USA. There was a strong correlation between length, width and weight
The importance of the Northeastern Gulf of Mexico to foraging loggerhead sea turtles
Identification of high-use foraging sites where imperiled sea turtles are resident remains a globally-recognized conservation priority. In the biodiverse Gulf of Mexico (GoM), recent telemetry studies highlighted post-nesting foraging sites for federally threatened loggerhead turtles (Caretta caretta). Our aim here was to discern loggerhead use of additional northern GoM regions that may serve as
Non-USGS Publications**
Williams,N.C., Bjorndal, K. A., Lamont, M.M., Carthy, R.R. 2014. Winter diets of immature green turtles (Chelonia mydas) on a northern feeding ground: integrating stomach contents and stable isotope analyses. Estuaries and Coasts. 37:986-994.
Lamont, M.M., Fujisaki, I., Carthy, R.R. 2014. Estimates of vital rates for a declining loggerhead turtle (Caretta caretta) subpopulation: implications for mangement. Marine Biology. 161:2659–2668 DOI 10.1007/s00227-014-2537-0
Nomani, S. Z., M. K. Oli, and R.R. Carthy. 2012. Line transects by design: the influence of study design, spatial distribution and density of objects on estimates of abundance. The Open Ecology Journal. 5: 25-44.
Shamblin, B.M., A.B. Bolten, K.A. Bjorndal, P.H. Dutton, J.T. Nielsen, F.A. Abreu-Grobois, K.J. Reich. B.E. Witherington, D.A. Bagley, L.M. Ehrhart, A.D. Tucker, D.S. Addison, A. Arenas, C. Johnson, R.R. Carthy, M.M. Lamont, M.G. Dodd, M.S. Gaines, E. LaCasella, and C.J. Nairn. 2012. Expanded mitochondrial control region sequences increase resolution of stock structure among North Atlantic loggerhead turtle rookeries. Marine Ecology Progress Series,. 469:145-160.
Salmon, M., R. Carthy, C. M.F. Lohmann, K. J. Lohmann, and J. Wyneken. 2012. Collecting a sample of loggerhead sea turtle hatchlings before a natural emergence does not reduce nest productivity. Endangered Species Research. 16: 296-299. doi: 10.3354/esr00409 IP-034556
**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.
Surface time for sea turtles in the Gulf of Mexico, 2010-2019
This dataset contains surface dive times, defined as 0-2 m in the water column, for three species of sea turtles (Kemp's ridleys, loggerheads, and green turtles) tracked via satellite telemetry in the Gulf of Mexico during periods within 2010-2019. It contains information on turtle species, location, proportion of time in "surface" bins, region of the Gulf of Mexico, corresponding remote
Mangrove distribution in the southeastern United States in 2021
Global climate change is leading to large-scale shifts in species' range limits. For example, rising winter temperatures are shifting the abundance and distributions of tropical, cold sensitive plant species towards higher latitudes. Coastal wetlands provide a prime example of such shifts, with tropical mangrove forests expanding into temperate salt marshes as winter warming alleviates past geogra
Preliminary data from animal borne cameras on loggerhead sea turtles in St. Joseph Bay, Florida (2018-2019)
This is a fifty-four second video which includes short segments compiled from video collected using GoPro cameras mounted on two individual loggerhead turtles (Caretta caretta) within St. Joseph Bay, Florida as part of a preliminary data release for U.S. Geological Survey (USGS) outreach publications. Approximately 90 minutes of video footage was collected per individual prior to retrieval. This i
Science and Products
- Publications
Filter Total Items: 51
Gopherus polyphemus (Gopher Tortoise) adult mortality
Gopherus polyphemus has typically high adult survivorship, with some populations reaching a mean annual survivorship of 93.4% (Howell et al. 2019. J. Wildl. Manage. 84:56–65). Instances of adult mortality are not commonly reported outside of large mortality events, and most often result from disease, starvation, dehydration, or chronic stress (Gates et al. 2002. Florida Sci. 65:185– 197; Cozad etGenetic diversity of immature Kemp's ridley (Lepidochelys kempii) sea turtles from the northern Gulf of Mexico
The Kemp’s ridley (Lepidochelys kempii) is the world’s most endangered sea turtle species. Predominately nesting at only one beach in Mexico, this species declined to an estimated 300 females in the mid-1980s. Conservation efforts in the United States and Mexico, including a head start programme in southern Texas in which hatchlings were reared in captivity for several months before being releasedIdentification of the Gulf of Mexico as an important high-use habitat for leatherback turtles from Central America
Endangered leatherback sea turtles (Dermochelys coriacea) are wide-ranging, long-distance migrants whose movements are often associated with environmental cues. We examined the spatial distribution and habitat use for 33 satellite-tracked leatherbacks from nesting beaches on the Caribbean coast of Costa Rica and Panama from 2004 to 2018, an important nesting population for the leatherback NorthwesUsing growth rates to estimate the minimum age and size at sexual maturity in a captive population of the critically endangered Central American river turtle Dermatemys mawii
The Central American river turtle Dermatemys mawii is a critically endangered species that has incurred substantial losses over the last several decades due to overhunting. This species is now being considered for head-starting programs (i.e. captive breeding of turtles for wild release). However, relatively little is known about their life history characteristics, especially with respect to growtUsing systems thinking to inform management of imperiled species: A case study with sea turtles
Management of imperiled species facing spatiotemporally dynamic threats is difficult. Systems thinking can inform their management by quantifying the impacts that they face. We apply systems thinking to the Northern Gulf of Mexico (NGM) loggerhead (Caretta caretta) Recovery Unit (RU), one of the smallest subpopulations of loggerheads nesting in the USA. We characterized disturbances to nests, manaEnvironmental factors predicting the orientation of sea turtle hatchlings on a naturally lighted beach: A baseline for light-management goals
On sea turtle nesting beaches, artificial lighting associated with human development interferes with hatchling orientation from nest to sea. Although hatchling disorientation has been documented for many beaches, data that managers can use in understanding, predicting, and managing the issue are of limited detail. The present study provides baseline hatchling orientation data that can be comparedTropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures
Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward‐moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold‐sensitive tropical organisms, sometimes at the expense of temperate organisms. AlthougHome ranges and movements of two diamondback terrapins (Malaclemys terrapin macrospilota) in northwest Florida
The diamondback terrapin (Malaclemys terrapin) is a small estuarine turtle distributed along the Atlantic and Gulf Coasts of the USA that is threatened by drowning in crab pots, road mortality, exploitation in the pet trade, and habitat loss. Little is known about the movement patterns and home ranges of these turtles, particularly along the U.S. Gulf of Mexico coast. Satellite tags were deployedUse of remote sensing tools to predict focal areas for sea turtle conservation in the Southwestern Atlantic
Fisheries bycatch of non-target species in the commercial fleet is a major source of anthropogenic injury and mortality for sea turtles and marine megafauna.The Río de la Plata maritime front (RLPMF) and its adjacent international waters – comprising part of the Argentine and Uruguayan exclusive economic zones, is a highly important fishing ground in the south-western Atlantic Ocean as well as feePredicting multi-species foraging hotspots for marine turtles in the Gulf of Mexico
Quantifying the distribution of animals and identifying underlying characteristics that define suitable habitat are essential for effective conservation of free-ranging species. Prioritizing areas for conservation is important in managing a geographic extent that has a high level of disturbance and limited conservation resources. We examined the potential use of a species distribution model ensembGrowth rates for immature Kemp’s ridley sea turtles from a foraging area in the northern Gulf of Mexico
Examining vital rates helps clarify how environmental characteristics, biological resources and human activities affect population growth. Carapace lengths were gathered for 241 Kemp’s ridley Lepidochelys kempii sea turtles that were marked and recaptured (n = 23) between 2011 and 2019 at a foraging location in northwest Florida, USA. There was a strong correlation between length, width and weightThe importance of the Northeastern Gulf of Mexico to foraging loggerhead sea turtles
Identification of high-use foraging sites where imperiled sea turtles are resident remains a globally-recognized conservation priority. In the biodiverse Gulf of Mexico (GoM), recent telemetry studies highlighted post-nesting foraging sites for federally threatened loggerhead turtles (Caretta caretta). Our aim here was to discern loggerhead use of additional northern GoM regions that may serve asNon-USGS Publications**
Williams,N.C., Bjorndal, K. A., Lamont, M.M., Carthy, R.R. 2014. Winter diets of immature green turtles (Chelonia mydas) on a northern feeding ground: integrating stomach contents and stable isotope analyses. Estuaries and Coasts. 37:986-994.Lamont, M.M., Fujisaki, I., Carthy, R.R. 2014. Estimates of vital rates for a declining loggerhead turtle (Caretta caretta) subpopulation: implications for mangement. Marine Biology. 161:2659–2668 DOI 10.1007/s00227-014-2537-0Nomani, S. Z., M. K. Oli, and R.R. Carthy. 2012. Line transects by design: the influence of study design, spatial distribution and density of objects on estimates of abundance. The Open Ecology Journal. 5: 25-44.Shamblin, B.M., A.B. Bolten, K.A. Bjorndal, P.H. Dutton, J.T. Nielsen, F.A. Abreu-Grobois, K.J. Reich. B.E. Witherington, D.A. Bagley, L.M. Ehrhart, A.D. Tucker, D.S. Addison, A. Arenas, C. Johnson, R.R. Carthy, M.M. Lamont, M.G. Dodd, M.S. Gaines, E. LaCasella, and C.J. Nairn. 2012. Expanded mitochondrial control region sequences increase resolution of stock structure among North Atlantic loggerhead turtle rookeries. Marine Ecology Progress Series,. 469:145-160.Salmon, M., R. Carthy, C. M.F. Lohmann, K. J. Lohmann, and J. Wyneken. 2012. Collecting a sample of loggerhead sea turtle hatchlings before a natural emergence does not reduce nest productivity. Endangered Species Research. 16: 296-299. doi: 10.3354/esr00409 IP-034556**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.
- Data
Surface time for sea turtles in the Gulf of Mexico, 2010-2019
This dataset contains surface dive times, defined as 0-2 m in the water column, for three species of sea turtles (Kemp's ridleys, loggerheads, and green turtles) tracked via satellite telemetry in the Gulf of Mexico during periods within 2010-2019. It contains information on turtle species, location, proportion of time in "surface" bins, region of the Gulf of Mexico, corresponding remoteMangrove distribution in the southeastern United States in 2021
Global climate change is leading to large-scale shifts in species' range limits. For example, rising winter temperatures are shifting the abundance and distributions of tropical, cold sensitive plant species towards higher latitudes. Coastal wetlands provide a prime example of such shifts, with tropical mangrove forests expanding into temperate salt marshes as winter warming alleviates past geograPreliminary data from animal borne cameras on loggerhead sea turtles in St. Joseph Bay, Florida (2018-2019)
This is a fifty-four second video which includes short segments compiled from video collected using GoPro cameras mounted on two individual loggerhead turtles (Caretta caretta) within St. Joseph Bay, Florida as part of a preliminary data release for U.S. Geological Survey (USGS) outreach publications. Approximately 90 minutes of video footage was collected per individual prior to retrieval. This i