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Pamela J Schofield, Ph.D.

Pam Schofield is a retired Research Fishery Biologist at the USGS Wetland and Aquatic Research Center. Pam retired in 2022 and is now a Scientist Emeritus.

Science and Products

Filter Total Items: 57

Risk assessment of chanchita Cichlasoma dimerus (Heckel, 1840), a newly identified non-native cichlid fish in Florida

The risk of a newly discovered non-native fish species in Florida (USA): Cichlasoma dimerus ([Heckel, 1840]; Family: Cichlidae) is assessed. Its tolerance to cold temperatures was experimentally evaluated and information on its biology and ecology was synthesized. In the cold-temperature tolerance experiment, temperature was lowered from 24 °C by increments of 1 °C per hour, mimicking a typical co
Authors
Mary Brown, Robert H. Robins, Pam Schofield
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Invasion frustration: Can biotic resistance explain the small geographic range of non-native croaking gourami Trichopsis vittata (Cuvier, 1831) in Florida, USA?

Croaking gourami Trichopsis vittata is a non-native fish species that has maintained a reproducing population in Florida, USA, since at least the 1970s. However, unlike most other non-native fishes in Florida, T. vittata has not spread beyond its very small (ca. 5 km²) range. We suspected the inability of T. vittata to colonize new habitats may be due to biotic resistance by the native eastern mos
Authors
Pam Schofield, Quenton M. Tuckett, Daniel Slone, Kristen Reaver, Jeffrey H. Hill
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Non-native Asian swamp eel, Monopterus albus/javanensis (Zuiew, 1973/Lacepede, 1800), responses to low temperatures

Asian swamp eel, Monopterus albus/javanensis [Zuiew, 1973/Lacepede 1800], has been established in the southeastern USA since at least 1994, yet little is known about its ability to survive low winter temperatures. We use standard thermal methodologies to quantify low temperature responses and provide a detailed description of swamp eel reactions to cold temperatures. When exposed to chronic temper
Authors
Ryan K. Saylor, Pam Schofield, Wayne A Bennett
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Expert bioblitzes facilitate non-native fish tracking and interagency partnerships

Documenting the distribution and composition of non-native species populations can be challenging, especially when species cross jurisdictional boundaries that require interagency coordination. Herein I report the development of three tools that have been used in Florida over the past seven years to assist with tracking of non-native fishes: 1) an overarching organization to increase coordination
Authors
Pamela J. Schofield
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

A comparison of the Trojan Y Chromosome strategy to harvesting models for eradication of nonnative species

The Trojan Y Chromosome strategy (TYC) is a promising eradication method for biological control of nonnative species. The strategy works by manipulating the sex ratio of a population through the introduction of supermales that guarantee male offspring. In the current study, we compare the TYC method with a pure harvesting strategy. We also analyze a hybrid harvesting model that mirrors the TYC str
Authors
Jingjing Lyu, Pamela J. Schofield, Kristen Reaver, Matthew Beauregard, Rana D. Parshad
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Genetic Characterization of Non-Native African Jewelfish, Hemichromis letourneuxi Sauvage 1880, in Florida

The African Jewelfish, Hemichromis letourneuxi, is an invasive, predatory cichlid fish introduced at least once to Florida. Its native range is in northern Africa. First encountered in Miami in the 1960s, it has since been found west and north within the State of Florida. It thrives in a wide range of aquatic habitats, including shallow, vegetated or rocky areas of canals, tidal creeks, rivers, an
Authors
Natalia M. Belfiore, Pamela J. Schofield
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Environmental DNA (eDNA) detection of nonnative bullseye snakehead in southern Florida

Bullseye Snakehead Channa marulius (Hamilton 1822) was first detected in the southern Florida town of Tamarac in 2000 and has been expanding its geographic range since. Environmental DNA (eDNA) analysis is a newly-developed technique used to noninvasively detect cryptic or low-density species or those that are logistically difficult-to-study. Genetic material shed into the environment through tis
Authors
Margaret Hunter, Pam Schofield, Gaia Meigs-Friend, Mary Brown, Jason Ferrante
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Non-native marine fishes in Florida: Updated checklist, population status and early detection/rapid response

It has been ten years since the last comprehensive assessment of non-native marine fishes in Florida. Herein, we report sightings of 41 species from Florida coastal waters since the earliest reported sighting in 1984. Information is provided on the population status of each species (e.g., established, eradicated, unknown), and our early detection/rapid response program to remove these fish is desc
Authors
Pamela J. Schofield, Lad Akins
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Eradication of two non-native cichlid fishes in Miami, Florida (USA)

The proliferation of non-native fishes in Florida is a serious problem, and new species continue to be introduced to the state. Fishes in the Family Cichlidae have been especially successful colonizers of south Florida freshwater habitats. Herein we report a multi-agency effort to eradicate two non-native cichlid fishes in Miami, Florida (Bay Snook Petenia splendida and Blue Mbuna Labeotropheus fu
Authors
Pamela J. Schofield, Howard L. Jelks, Kelly B. Gestring
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Introduction and dispersal of non-native bullseye snakehead Channa marulius (Hamilton, 1822) in the canal system of southeastern Florida, USA

An established population of bullseye snakehead (Channa marulius), a large predatory fish from southeastern Asia, was identified for the first time in North America from waters in southeastern Florida, USA, in the year 2000. Since then, it has dispersed throughout the extensive canal system in the area from West Palm Beach south to Miramar. Collection data were compiled to determine the extent of
Authors
Amy J. Benson, Pamela J. Schofield, Kelly B. Gestring
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Salinity tolerance among three freshwater mussels (Bivalvia: Unionidae) from Gulf Coastal Plain drainages

An important physiological constraint influencing distributions of coastal freshwater organisms is their tolerance for saline conditions. We experimentally evaluated salinity tolerance for three freshwater mussel species (Utterbackia imbecillis, Elliptio jayensis, and Glebula rotundata). Mussels were transferred abruptly from well water to one of five treatments (0 [control], 6, 12, 18 or 24 parts
Authors
Nathan A. Johnson, Pamela J. Schofield, James D. Williams, James D. Austin
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Lower lethal temperatures for nonnative freshwater fishes in Everglades National Park, Florida

Temperature is an important factor that shapes biogeography and species composition. In southern Florida, the tolerance of nonnative freshwater fishes to low temperatures is a critical factor in delineating their geographic spread. In this study, we provide empirical information on experimentally derived low-temperature tolerance limits of Banded Cichlid Heros severus and Spotfin Spiny Eel Macrogn
Authors
Pamela J. Schofield, Jeffrey L. Kline
By
Ecosystems Mission Area, Wetland and Aquatic Research Center

Non-USGS Publications**

Schofield, P.J. & D.H. Huge. 2011. Low-temperature tolerance of two non-native fishes (Hoplosternum littorale [Hancock 1828], Cichlasoma bimaculatum [Linnaeus 1758]) established in Florida. Florida Scientist 74: 73-83.
Schofield, P.J. & L.J. Chapman. 1999. Interactions between Nile perch, Lates niloticus, and other fishes in Lake Nabugabo, Uganda. Environmental Biology of Fishes 55(4): 343-358.
Schofield, P.J. & G.H. Burgess. 1997. Etmopterus robinsi: A new species of deep-water dogshark (Elasmobranchii, Etmopteridae) from the Caribbean and Western Atlantic with a redescription of E. hillianus. Bulletin of Marine Science 60(3): 1060-1073.
Kolar, C. and P. Schofield. 2009. Early detection and rapid response for nonnative marine fishes. Fisheries and Aquatic Bulletin (USGS) 9:7-9.
Schofield, P.J. 2003. Factors affecting the distribution and densities of two gobies (Microgobius gulosus and Gobiosoma robustum) in a lagoonal estuarine system (Florida Bay, USA). Doctoral dissertation, Department of Biological Sciences, University of Southern Mississippi.

**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.

Filter Total Items: 25
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Male Midas cichlid

Fish Slam May 2023

Fish Slam events link research institutions such as museums and universities with federal, state, and local government agencies that possess expertise and field equipment to collect nonnative fishes, providing unique access to specimens for these institutions.
By
Wetland and Aquatic Research Center
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Fish Slam May 2023

Fish Slam events link research institutions such as museums and universities with federal, state, and local government agencies that possess expertise and field equipment to collect nonnative fishes, providing unique access to specimens for these institutions.
Learn More
link
Mayan cichlid

Southwest Florida Fish Slam – Spring 2022

Forty-two fish biologists from seven organizations participated in a two-day Spring Fish Slam event in southwest Florida. Fourteen species of non-native fishes were collected or observed.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Land Management Research Program, Wetland and Aquatic Research Center
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Southwest Florida Fish Slam – Spring 2022

Forty-two fish biologists from seven organizations participated in a two-day Spring Fish Slam event in southwest Florida. Fourteen species of non-native fishes were collected or observed.
Learn More
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Mayan cichlid, Mayaheros urophthalmus

Virtual Fish Slam - March 2021

In March 2021, USGS researchers and partners conducted the first-ever Virtual Fish Slam. The bi-annual Fish Slam event helps monitor new introductions and document range expansion of known non-native freshwater fishes.
By
Biological Threats and Invasive Species Research Program, Wetland and Aquatic Research Center
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Virtual Fish Slam - March 2021

In March 2021, USGS researchers and partners conducted the first-ever Virtual Fish Slam. The bi-annual Fish Slam event helps monitor new introductions and document range expansion of known non-native freshwater fishes.
Learn More
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Blotched foxface rabbitfish (Siganus unimaculatus)

Early Detection and Rapid Response: Removal of Newly Introduced Non-native Marine Fishes to Prevent Invasions

USGS WARC works with partners on early detection and rapid response (ED/RR) efforts, rapidly removing newly introduced non-native marine fishes from Florida’s coastal waters to prevent invasions.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Wetland and Aquatic Research Center
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Early Detection and Rapid Response: Removal of Newly Introduced Non-native Marine Fishes to Prevent Invasions

USGS WARC works with partners on early detection and rapid response (ED/RR) efforts, rapidly removing newly introduced non-native marine fishes from Florida’s coastal waters to prevent invasions.
Learn More
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Lionfish are spreading through the Western North Atlantic, Caribbean Sea, and the Gulf of Mexico

Non-native Marine Fishes: Tracking Distributions with the USGS Nonindigenous Aquatic Species Database

WARC scientists work with local partners to verify and document sightings of non-native marine fishes.
By
Wetland and Aquatic Research Center
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Non-native Marine Fishes: Tracking Distributions with the USGS Nonindigenous Aquatic Species Database

WARC scientists work with local partners to verify and document sightings of non-native marine fishes.
Learn More
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Lionfish on Looe Reef, Florida Keys National Marine Sanctuary

Non-native Marine Fishes Observed or Collected in Florida Waters

Below is a list of non-native marine fish species observed or collected in Florida. Each species is linked to a fact sheet with information on identification, biology and ecology. Maps indicate species occurrences linked to USGS-NAS data, which is available for download. Data may be downloaded directly from the map page of a particular species or you can contact Dr. Pam Schofield directly with your inquiry.

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Non-native Marine Fishes Observed or Collected in Florida Waters

Below is a list of non-native marine fish species observed or collected in Florida. Each species is linked to a fact sheet with information on identification, biology and ecology. Maps indicate species occurrences linked to USGS-NAS data, which is available for download. Data may be downloaded directly from the map page of a particular species or you can contact Dr. Pam Schofield directly with your inquiry.

Learn More
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Chocolate surgeonfish spotted in Florida waters

Non-native Marine Fishes in Florida - By Family

Below are families of non-native marine fish species observed or collected in Florida. Species within each family are linked to a fact sheet with information on identification, biology and ecology. Maps indicate species occurrences linked to USGS-NAS data, which is available for download. Data may be downloaded directly from the map page of a particular species or you can contact Dr. Pam Schofield directly with your inquiry.

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Non-native Marine Fishes in Florida - By Family

Below are families of non-native marine fish species observed or collected in Florida. Species within each family are linked to a fact sheet with information on identification, biology and ecology. Maps indicate species occurrences linked to USGS-NAS data, which is available for download. Data may be downloaded directly from the map page of a particular species or you can contact Dr. Pam Schofield directly with your inquiry.

Learn More
link
Lionfish on Looe Reef, Florida Keys National Marine Sanctuary

Non-native Marine Fishes in Florida

Learn which non-native marine fish species have been observed or collected Florida waters. 

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Non-native Marine Fishes in Florida

Learn which non-native marine fish species have been observed or collected Florida waters. 

Learn More
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Barton, Fair, Markovich, and Gestring

Fish Chat and Slam November 2019

Fifty fish biologists from 15 organizations participated in a three-day Fish Chat and Slam event in South Florida on November 5-7, 2019.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Land Management Research Program, Wetland and Aquatic Research Center
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Fish Chat and Slam November 2019

Fifty fish biologists from 15 organizations participated in a three-day Fish Chat and Slam event in South Florida on November 5-7, 2019.
Learn More
link
Mayan cichlid

Treasure Coast and Central Florida Fish Slams - 2019

In March and June 2019, USGS researchers joined partners in Treasure Coast and Central Florida where they sampled freshwater bodies for non-native fishes. The bi-annual Fish Slam event helps monitor new introductions and document range expansion of known non-native fishes.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Wetland and Aquatic Research Center
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Treasure Coast and Central Florida Fish Slams - 2019

In March and June 2019, USGS researchers joined partners in Treasure Coast and Central Florida where they sampled freshwater bodies for non-native fishes. The bi-annual Fish Slam event helps monitor new introductions and document range expansion of known non-native fishes.
Learn More
link
Color varieties of Midas cichlid, Amphilophus citrinellus

Fish Slam November 2018

In November 2018, USGS researchers joined partners in South Florida where they sampled freshwater bodies for non-native fishes. The bi-annual Fish Slam event helps monitor new introductions and document range expansion of known non-native fishes.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Land Management Research Program, Wetland and Aquatic Research Center
link

Fish Slam November 2018

In November 2018, USGS researchers joined partners in South Florida where they sampled freshwater bodies for non-native fishes. The bi-annual Fish Slam event helps monitor new introductions and document range expansion of known non-native fishes.
Learn More
link
An apple snail in the experimental mesocosm with individual markings

Effects of Native and Non-native Fishes on Native Apple Snail Population Dynamics

The Florida apple snail is a critical component of the state's wetland food webs. USGS scientists assess the effects of native and non-native fishes on the native snail populations.
By
Ecosystems Mission Area, Biological Threats and Invasive Species Research Program, Species Management Research Program, Wetland and Aquatic Research Center
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Effects of Native and Non-native Fishes on Native Apple Snail Population Dynamics

The Florida apple snail is a critical component of the state's wetland food webs. USGS scientists assess the effects of native and non-native fishes on the native snail populations.
Learn More
Filter Total Items: 16

Risk assessment of chanchita Cichlasoma dimerus (Heckel, 1840), a newly identified non-native cichlid fish in Florida

Cichlasoma dimerus was only recently discovered in Florida and little is known of its dispersal abilities and potential impacts. Many factors likely contribute to the variability in establishment and spread of non-native fishes in Florida, including biotic (e.g., predation and competition) and abiotic variables (e.g., cold tolerance, low-oxygen tolerance). Of the abiotic variables, cold tolerance
By
Wetland and Aquatic Research Center

Non-native Asian swamp eel, Monopterus albus/javanensis (Zuiew, 1973/Lacepede, 1800), responses to low temperatures

Asian swamp eel, Monopterus albus/javanensis [Zuiew, 1973/Lacepede, 1800], has been established in the southeastern USA since at least 1994, yet little is known about its ability to survive low winter temperatures. We use standard thermal methodologies to quantify low-temperature responses and provide a detailed description of swamp eel reactions to cold temperatures. When exposed to chronic tempe
By
Wetland and Aquatic Research Center

Trojan Y chromosome strategy for eradication of non-native species data

The Trojan Y Chromosome (TYC) strategy is a promising eradication method for biological control of non-native species. The strategy works by manipulating the sex ratio of a population through the introduction of supermales that guarantee male offspring.
By
Wetland and Aquatic Research Center

Can biotic resistance explain the small geographic range of non-native croaking gourami Trichopsis vittata (Cuvier, 1831) in Florida, USA?

In this report, we evaluate this hypothesis for croaking gourami Trichopsis vittata, a non-native species that has established a reproducing population, but has not successfully spread beyond its very small (5 km2) range. We suspected the inability of T. vittata to colonize new habitats may be due to biotic resistance by the native eastern mosquitofish Gambusia holbrooki.
By
Wetland and Aquatic Research Center

Non-native marine fishes in Florida: updated checklist, population status and early detection/rapid response data

It has been ten years since the last comprehensive assessment of non-native marine fishes in Florida. Herein, we report sightings of 41 species from Florida coastal waters since the earliest sighting in 1984.
By
Wetland and Aquatic Research Center

Bioblitzes facilitate non-native fish tracking and interagency partnerships data

Maintaining up-to-date information on non-native organisms' distributions and species composition can be difficult, especially when species cross jurisdictional boundaries that require interagency coordination. Herein I report on the use of tools that have been used in Florida over the past seven years to assist with tracking of non-native fishes. Ten Fish Slams, where professional biologists and
By
Wetland and Aquatic Research Center

Hemichromis collection data for genetic characterization in Florida

The African Jewelfish, Hemichromis letourneuxi, is an invasive, predatory cichlid fish introduced at least once to Florida. Its native range is in northeastern Africa. First encountered in Miami in the 1960s, it has since been found west and north within the state of Florida. It thrives in a wide range of aquatic habitats, including shallow, vegetated or rocky areas of canals, tidal creeks, rivers
By
Wetland and Aquatic Research Center

Bullseye snakehead environmental DNA data, and associated attributes, collected from southeast Florida, from 2015-2018

Bullseye snakehead, Channa marulius, was first detected in 2000 in the southern Florida town of Tamarac and has been expanding its geographic range. Environmental DNA (eDNA) analysis is a newly-developed technique used to non-invasively detect cryptic or low-density species, or those that are logistically difficult to study. Genetic material shed into the environment through tissue and body fluid
By
Biological Threats and Invasive Species Research Program, Wetland and Aquatic Research Center

Removing threats before they spread: Eradication of two non-native fishes in Miami, Florida (USA)

The proliferation of non-native fishes in Florida is a serious problem, and new species continue to be introduced to the State. Herein we report the eradication of two species of non-native fishes in Miami, Florida (Giant Cichlid Petenia splendida and Blue Mbuna Labeotropheus fuelleborni; both Family: Cichlidae). We removed these fishes before they were observed in the extensive, interconnected ca
By
Wetland and Aquatic Research Center

Observations of bullseye snakehead (Channa marulius) in Florida

This dataset contains information on the Bullseye Snakehead fish found only in southeastern Florida. It is a subset of a larger database, the Nonindigenous Aquatic Species Database (NAS). This information resource is an established central repository for spatially referenced biogeographic accounts of introduced aquatic species. The NAS website provides scientific reports, online/real-time queries,
By
Wetland and Aquatic Research Center

Salinity tolerance among three freshwater mussels (Bivalvia: Unionidae) from Gulf Coastal Plain drainages

An important physiological constraint influencing distributions of coastal freshwater organisms is their tolerance for saline conditions. We experimentally evaluated salinity tolerance for three freshwater mussel species (Utterbackia imbecillis, Elliptio jayensis, and Glebula rotundata). Mussels were transferred abruptly from well water to one of five treatments (0 [control], 6, 12, 18 or 24 parts
By
Wetland and Aquatic Research Center

Review of low-temperature tolerance data for 17 species of non-native fishes that have been observed in Everglades National Park

Temperature is an important factor in understanding biogeography and species composition. In south Florida, non-native fishes' tolerance to low temperatures is a critical factor in delineating their geographic spread. We provide a literature review summarizing the current state of knowledge of low-temperature tolerances for all seventeen non-native fishes that have been found in Everglades Nationa
By
Wetland and Aquatic Research Center
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USGS and Partners Team Up to Track Down Nonnative and Invasive Fishes in South Florida

The Fish Slam event discovered two nonnative fish species never seen before in Big Cypress National Preserve.

 

 

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Blotched Foxface Fish Found in Florida Waters

Fish Marks 36th Non-Native Marine Fish Species Found in State

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Taming the Lion(fish)

Genetics and tracking helps USGS researchers learn where the invasive fish are now – and where they may go next.

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Walking catfish
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