Donald Tillitt, PhD (Former Employee)
Science and Products
Thiamine (Vitamin B1) Deficiency in Fish and Wildlife
In the last few decades, thiamine deficiency has been observed in fish and wildlife in the Great Lakes, Alaska, Sweden and several other areas in North America and Europe. Thiamine is an essential vitamin needed for cell function. Thiamine deficiency has been linked to neurological disorders, immunosuppression, and lower reproductive viability. These disorders potentially reduce populations of...
Effects of estrogens and atrazine on functional immune responses of largemouth bass (Micropterus salmoides)
Disease outbreaks, skin lesions, fish kill events, and reproductive abnormalities have been observed in wild populations of bass in the Chesapeake Bay watershed. Occurrence of synthetic and natural hormones from wastewater treatment plants and livestock operations, pesticides from agricultural lands, and phytoestrogens from cover crops have been implicated as potential causes of these...
Alternative complement pathway assay data for adult largemouth bass exposed in outdoor ponds to 17alpha-ethinylestradiol or an estrone-atrazine mixture
Alternative complement pathway assay data observed in adult largemouth bass plasma in response to an EE2 (17alpha-ethinylestradiol) or mixture of estrone and atrazine exposure under laboratory pond conditions, with associated fish identification information.
Egg thiamine content, length, weight and survival of steelhead (Oncorhynchus mykiss) exposed to three methods of experimental thiamine supplementation in 2022 and egg thiamine content from three Oregon hatcheries in 2019
Early rearing of steelhead (Oncorhynchus mykiss) in Oregon hatcheries is often problematic; fry can become emaciated and die during the period between hatch and first feed. Thiamine (vitamin B1) deficiency has caused early mortality in salmonids; however, thiamine status of Oregon’s anadromous steelhead populations is currently unknown. We sampled eggs of 7-10 females during spawning...
Quantitation of estrogens in water, alone and in combination with atrazine, using two chemically-activated luciferase expression, CALUX, bioassays and quadrupole-time of flight ultraperformance liquid chromatography/mass spectrometry, UPLC-MS
This data describes the relative luminescence units and relative fluorescence units of lysates of two estrogen responsive chemically-activated luciferase expression human breast VM7Luc4E2 and VM7LucERbc9 cells which were exposed for 24 hours to estrone and 17beta-estradiol dilutions alone and in mixture with atrazine or water extracts collected from dilutor tanks during a fish exposure...
Water chemistry and fish metrics data for adult largemouth bass exposed in outdoor ponds to 17alpha-ethinylestradiol or an estrone-atrazine mixture
Physiological endpoints observed in adult largemouth bass in response to an EE2 (17 alpha-ethinylestradiol) or mixture of estrone and atrazine exposure under laboratory pond conditions. Also included are water quality and chemical concentration data. Adult LMB were exposed in outdoor pond mesocosms from post-spawning to early gonad recrudescence to either EE2 (2.4 nanograms per liter)...
Dissolved organic carbon, total petroleum hydrocarbons and and toxicity assay results for Bemidji, MN (2018)
In crude-oil-contaminant plumes the dissolved organic carbon (DOC) is mainly hydrocarbon degradation intermediates only partly quantified by the diesel range total petroleum hydrocarbon (TPHd) method. To understand potential biological effects of degradation intermediates we tested three fractions of DOC: (1) solid phase extract (HLB); (2) dichloromethane (DCM-total) extract used in TPHd...
Baseline fish health metrics in at-risk habitats critical for pallid sturgeon (Scaphirhynchus albus) in the Upper Missouri River Basin and bull trout (Salvelinus confluentus) in the Flathead River, Montana, 2017-18
Baseline fish health information on pallid sturgeon and bull trout or appropriate surrogate species (shovelnose sturgeon, cutthroat trout, mountain whitefish) in critical habitats with elevated risks of oil spills. Shovelnose sturgeon (Scaphirhynchus platorynchus) were collected in three locations near the confluence of the Missouri and Yellowstone Rivers and cutthroat trout...
Thiamine concentrations in lake trout eggs collected from the Great Lakes in 2019-20
Text files containing data regarding attributes of lake trout egg thiamine concentrations from sites in lakes Huron and Michigan collected during 2019-20, sampling site locations and quality assurance quality control values for comparison to previous years (2017-18) lake trout egg thiamine concentrations.
Effects of early life stage exposure of largemouth bass to atrazine or a model estrogen (17a-ethinylestradiol)
Largemouth base histological development and transcriptomic changes in gonad tissue after early life stage exposure to Atrazine (1-Chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine) or the model estrogen 17a-ethinylestradiol.
USGS Great Lakes lake trout egg thiamine monitoring data release
Monitoring of vitamin B1 (thiamine) in the eggs of lake trout (Salvelinus namaycush) collected from lakes Huron and Michigan has been conducted by the U.S. Geological Survey since the mid-1990?s. The results of this monitoring effort have been used by natural resource management agencies and native American tribes within the Great Lakes basin to evaluate the reproductive health of lake...
Acute toxicity and clotting times of anticoagulant rodenticides to red-toothed (Odonus niger) and black (Melichthys niger) triggerfish, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides)
Acute toxicity and clotting times of anticoagulant rodenticides of four fish species
Development of a dual luciferase-fluorescamine assay adapted to a 384 micro-well plate format-Data
We have adapted two commonly used human breast luciferase transactivation cell bioassays, the recently re-named estrogen agonist/antagonist screening VM7Luc4E2 cell bioassay (previously designated BG1Luc4E2) and the androgen/glucocorticoid screening MDA-kb2 cell bioassay, to 384-well formats for HTS of endocrine-active substances. This cost-saving adaptation includes a fast, accurate...
Filter Total Items: 216
Immunomodulation in adult largemouth bass (Micropterus salmoides) exposed to a model estrogen or mixture of endocrine disrupting contaminants during early gonadal recrudescence
Disease outbreaks, skin lesions, fish kill events, and reproductive abnormalities have been observed in wild populations of Centrarchids in watersheds throughout the United States. Occurrence of synthetic and natural hormones from wastewater treatment plants and livestock operations, pesticides from agricultural land use, and phytoestrogens have been implicated as potential causes of...
Authors
Jessica Kristin Leet, Catherine A. Richter, Rachel Claunch, Robert W. Gale, Donald E. Tillitt, Luke Iwanowicz
Evolutionary and ecological correlates of thiaminase in fishes
Thiamine (vitamin B1) is required by all living organisms in multiple metabolic pathways. It is scarce in natural systems, and deficiency can lead to reproductive failure, neurological issues, and death. One major cause of thiamine deficiency is an overreliance on diet items containing the enzyme thiaminase. Thiaminase activity has been noted in many prey fishes and linked to cohort...
Authors
Freya Elizabeth Rowland, Catherine A. Richter, Donald E. Tillitt, David C Walters
Reevaluation of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalency factors for dioxin-like polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls for fishes
An expert meeting was organized by the World Health Organization (WHO) in 1997 to streamline assessments of risk posed by mixtures of dioxin-like chemicals (DLCs) through development of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) equivalency factors (TEFs) for mammals, birds, and fishes. No reevaluation has been performed for fish TEFs. Therefore, the objective of the present...
Authors
Jon A. Doering, Donald E. Tillitt, Steve Wiseman
Factors influencing egg thiamine concentrations of Lake Ontario lake trout: 2019–2020
In the Great Lakes region, thiamine deficiency is considered a recruitment bottleneck for lake trout Salvelinus namaycush and has been correlated with the consumption of non-native alewife Alosa pseudoharengus. While alewife, the most abundant forage fish in Lake Ontario, are the predominant prey for lake trout, they also consume benthic prey such as round goby Neogobius melanostomus...
Authors
Aaron C. Heisey, Christopher Osborne, Brian F. Lantry, Donald E. Tillitt, Jacques Rinchard
Understanding and mitigating thiaminase activity in silver carp
A deficiency of thiamine (vitamin B1), an essential cofactor for enzymes involved in metabolic processes, can be caused by the enzyme thiaminase. Thiaminase in food stocks has been linked to morbidity and mortality due to thiamine depletion in many ecologically and economically important species. Thiaminase activity has been detected in certain bacteria, plants, and fish species...
Authors
Patricia C. Wolfe, Amber M. Tuske, Donald E. Tillitt, Fred Allen, Katie A. Edwards
Thiamine supplementation improves survival and body condition of hatchery-reared steelhead (Oncorhynchus mykiss) in Oregon
Early rearing of steelhead (Oncorhynchus mykiss) in Oregon hatcheries is often problematic; fry can become emaciated and die during the period between hatch and first feed. Thiamine (vitamin B1) deficiency has caused early mortality in salmonids; however, the thiamine status of Oregon’s steelhead populations is unknown, to date. Of the 26 egg samples from three Oregon hatcheries in 2019...
Authors
Aimee N. Reed, Freya Elizabeth Rowland, Jennifer A. Krajcik, Donald E. Tillitt
Genetic basis of thiaminase I activity in a vertebrate, zebrafish Danio rerio
Thiamine (vitamin B1) metabolism is an important driver of human and animal health and ecological functioning. Some organisms, including species of ferns, mollusks, and fish, contain thiamine-degrading enzymes known as thiaminases, and consumption of these organisms can lead to thiamine deficiency in the consumer. Consumption of fish containing thiaminase has led to elevated mortality...
Authors
Catherine A. Richter, Allison N. Evans, Scott A. Heppell, James L. Zajicek, Donald E. Tillitt
Comparison of two estrogen chemically activated luciferase expression cell bioassays to liquid chromatography–mass spectrometry for quantifying estrone in water samples
Chemically activated luciferase expression (CALUX) cell bioassays are popular tools for assessing endocrine activity of chemicals such as certain environmental contaminants. Although activity equivalents can be obtained from CALUX analysis, directly comparing these equivalents to those obtained from analytical chemistry methods can be problematic because of the complexity of endocrine...
Authors
Jennifer Brennan, Abigail Henke, Robert W. Gale, Diane Nicks, Donald E. Tillitt
Declines in reproductive condition of male largemouth bass (Micropterus salmoides) following seasonal exposure to estrogenic endocrine-disrupting compounds
Reproductive abnormalities, that could lead to possible effects at the population level, have been observed in wild fish throughout the United States, with high prevalence in largemouth bass (LMB; Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Estrone (E1) and atrazine (ATR) are common environmental contaminants often associated with agricultural land use. 17alpha...
Authors
Jessica Kristin Leet, Catherine A. Richter, Robert W. Gale, Donald E. Tillitt, Jill A. Jenkins
Exposure to 17α-ethinylestradiol results in differential susceptibility of largemouth bass (Micropterus salmoides) to bacterial infection
Disease outbreaks, skin lesions, mortality events, and reproductive abnormalities have been observed in wild populations of centrarchids. The presence of estrogenic endocrine disrupting compounds (EEDCs) has been implicated as a potential causal factor for these effects. The effects of prior EEDC exposure on immune response were examined in juvenile largemouth bass (Micropterus salmoides...
Authors
Jessica Kristin Leet, Justin Blaine Greer, Catherine A. Richter, Luke Iwanowicz, Edward Spinard, Jacquelyn McDonald, Carla M. Conway, Robert W. Gale, Donald E. Tillitt, John D. Hansen
Response to Gard et al.'s (2021) Comments on the Critical Review “Polychlorinated Biphenyl Tissue-Concentration Thresholds for Survival, Growth, and Reproduction in Fish”
This response is offered to the critique by Gard et al. (2021) of our meta-analysis of polychlorinated biphenyl (PCB)-induced toxicity data in fish (Berninger and Tillitt 2019). Gard et al. (2021) offered numerous comments, the most substantive suggesting that 1) we should have added no-observable–adverse effect residue (NOAER) data from additional studies and all data points from...
Authors
Jason P. Berninger, Donald E. Tillitt
Reproduction
Lake charr Salvelinus namaycush are typically fall spawners although one ecotype has populations that spawn during spring and fall (siscowets in Lake Superior). Lake charr are iteroparous (reproduce more than once in a lifetime) with group-synchronous ovarian development and typically spawn once per year. However, lake charr may not reproduce every year, a phenomenon known as skipped...
Authors
Frederick W. Goetz, J. Ellen Marsden, Catherine A. Richter, Donald E. Tillitt, Shawn P. Sitar, Stephen Riley, Charles C. Krueger
Science and Products
Thiamine (Vitamin B1) Deficiency in Fish and Wildlife
In the last few decades, thiamine deficiency has been observed in fish and wildlife in the Great Lakes, Alaska, Sweden and several other areas in North America and Europe. Thiamine is an essential vitamin needed for cell function. Thiamine deficiency has been linked to neurological disorders, immunosuppression, and lower reproductive viability. These disorders potentially reduce populations of...
Effects of estrogens and atrazine on functional immune responses of largemouth bass (Micropterus salmoides)
Disease outbreaks, skin lesions, fish kill events, and reproductive abnormalities have been observed in wild populations of bass in the Chesapeake Bay watershed. Occurrence of synthetic and natural hormones from wastewater treatment plants and livestock operations, pesticides from agricultural lands, and phytoestrogens from cover crops have been implicated as potential causes of these...
Alternative complement pathway assay data for adult largemouth bass exposed in outdoor ponds to 17alpha-ethinylestradiol or an estrone-atrazine mixture
Alternative complement pathway assay data observed in adult largemouth bass plasma in response to an EE2 (17alpha-ethinylestradiol) or mixture of estrone and atrazine exposure under laboratory pond conditions, with associated fish identification information.
Egg thiamine content, length, weight and survival of steelhead (Oncorhynchus mykiss) exposed to three methods of experimental thiamine supplementation in 2022 and egg thiamine content from three Oregon hatcheries in 2019
Early rearing of steelhead (Oncorhynchus mykiss) in Oregon hatcheries is often problematic; fry can become emaciated and die during the period between hatch and first feed. Thiamine (vitamin B1) deficiency has caused early mortality in salmonids; however, thiamine status of Oregon’s anadromous steelhead populations is currently unknown. We sampled eggs of 7-10 females during spawning...
Quantitation of estrogens in water, alone and in combination with atrazine, using two chemically-activated luciferase expression, CALUX, bioassays and quadrupole-time of flight ultraperformance liquid chromatography/mass spectrometry, UPLC-MS
This data describes the relative luminescence units and relative fluorescence units of lysates of two estrogen responsive chemically-activated luciferase expression human breast VM7Luc4E2 and VM7LucERbc9 cells which were exposed for 24 hours to estrone and 17beta-estradiol dilutions alone and in mixture with atrazine or water extracts collected from dilutor tanks during a fish exposure...
Water chemistry and fish metrics data for adult largemouth bass exposed in outdoor ponds to 17alpha-ethinylestradiol or an estrone-atrazine mixture
Physiological endpoints observed in adult largemouth bass in response to an EE2 (17 alpha-ethinylestradiol) or mixture of estrone and atrazine exposure under laboratory pond conditions. Also included are water quality and chemical concentration data. Adult LMB were exposed in outdoor pond mesocosms from post-spawning to early gonad recrudescence to either EE2 (2.4 nanograms per liter)...
Dissolved organic carbon, total petroleum hydrocarbons and and toxicity assay results for Bemidji, MN (2018)
In crude-oil-contaminant plumes the dissolved organic carbon (DOC) is mainly hydrocarbon degradation intermediates only partly quantified by the diesel range total petroleum hydrocarbon (TPHd) method. To understand potential biological effects of degradation intermediates we tested three fractions of DOC: (1) solid phase extract (HLB); (2) dichloromethane (DCM-total) extract used in TPHd...
Baseline fish health metrics in at-risk habitats critical for pallid sturgeon (Scaphirhynchus albus) in the Upper Missouri River Basin and bull trout (Salvelinus confluentus) in the Flathead River, Montana, 2017-18
Baseline fish health information on pallid sturgeon and bull trout or appropriate surrogate species (shovelnose sturgeon, cutthroat trout, mountain whitefish) in critical habitats with elevated risks of oil spills. Shovelnose sturgeon (Scaphirhynchus platorynchus) were collected in three locations near the confluence of the Missouri and Yellowstone Rivers and cutthroat trout...
Thiamine concentrations in lake trout eggs collected from the Great Lakes in 2019-20
Text files containing data regarding attributes of lake trout egg thiamine concentrations from sites in lakes Huron and Michigan collected during 2019-20, sampling site locations and quality assurance quality control values for comparison to previous years (2017-18) lake trout egg thiamine concentrations.
Effects of early life stage exposure of largemouth bass to atrazine or a model estrogen (17a-ethinylestradiol)
Largemouth base histological development and transcriptomic changes in gonad tissue after early life stage exposure to Atrazine (1-Chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine) or the model estrogen 17a-ethinylestradiol.
USGS Great Lakes lake trout egg thiamine monitoring data release
Monitoring of vitamin B1 (thiamine) in the eggs of lake trout (Salvelinus namaycush) collected from lakes Huron and Michigan has been conducted by the U.S. Geological Survey since the mid-1990?s. The results of this monitoring effort have been used by natural resource management agencies and native American tribes within the Great Lakes basin to evaluate the reproductive health of lake...
Acute toxicity and clotting times of anticoagulant rodenticides to red-toothed (Odonus niger) and black (Melichthys niger) triggerfish, fathead minnow (Pimephales promelas), and largemouth bass (Micropterus salmoides)
Acute toxicity and clotting times of anticoagulant rodenticides of four fish species
Development of a dual luciferase-fluorescamine assay adapted to a 384 micro-well plate format-Data
We have adapted two commonly used human breast luciferase transactivation cell bioassays, the recently re-named estrogen agonist/antagonist screening VM7Luc4E2 cell bioassay (previously designated BG1Luc4E2) and the androgen/glucocorticoid screening MDA-kb2 cell bioassay, to 384-well formats for HTS of endocrine-active substances. This cost-saving adaptation includes a fast, accurate...
Filter Total Items: 216
Immunomodulation in adult largemouth bass (Micropterus salmoides) exposed to a model estrogen or mixture of endocrine disrupting contaminants during early gonadal recrudescence
Disease outbreaks, skin lesions, fish kill events, and reproductive abnormalities have been observed in wild populations of Centrarchids in watersheds throughout the United States. Occurrence of synthetic and natural hormones from wastewater treatment plants and livestock operations, pesticides from agricultural land use, and phytoestrogens have been implicated as potential causes of...
Authors
Jessica Kristin Leet, Catherine A. Richter, Rachel Claunch, Robert W. Gale, Donald E. Tillitt, Luke Iwanowicz
Evolutionary and ecological correlates of thiaminase in fishes
Thiamine (vitamin B1) is required by all living organisms in multiple metabolic pathways. It is scarce in natural systems, and deficiency can lead to reproductive failure, neurological issues, and death. One major cause of thiamine deficiency is an overreliance on diet items containing the enzyme thiaminase. Thiaminase activity has been noted in many prey fishes and linked to cohort...
Authors
Freya Elizabeth Rowland, Catherine A. Richter, Donald E. Tillitt, David C Walters
Reevaluation of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalency factors for dioxin-like polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls for fishes
An expert meeting was organized by the World Health Organization (WHO) in 1997 to streamline assessments of risk posed by mixtures of dioxin-like chemicals (DLCs) through development of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) equivalency factors (TEFs) for mammals, birds, and fishes. No reevaluation has been performed for fish TEFs. Therefore, the objective of the present...
Authors
Jon A. Doering, Donald E. Tillitt, Steve Wiseman
Factors influencing egg thiamine concentrations of Lake Ontario lake trout: 2019–2020
In the Great Lakes region, thiamine deficiency is considered a recruitment bottleneck for lake trout Salvelinus namaycush and has been correlated with the consumption of non-native alewife Alosa pseudoharengus. While alewife, the most abundant forage fish in Lake Ontario, are the predominant prey for lake trout, they also consume benthic prey such as round goby Neogobius melanostomus...
Authors
Aaron C. Heisey, Christopher Osborne, Brian F. Lantry, Donald E. Tillitt, Jacques Rinchard
Understanding and mitigating thiaminase activity in silver carp
A deficiency of thiamine (vitamin B1), an essential cofactor for enzymes involved in metabolic processes, can be caused by the enzyme thiaminase. Thiaminase in food stocks has been linked to morbidity and mortality due to thiamine depletion in many ecologically and economically important species. Thiaminase activity has been detected in certain bacteria, plants, and fish species...
Authors
Patricia C. Wolfe, Amber M. Tuske, Donald E. Tillitt, Fred Allen, Katie A. Edwards
Thiamine supplementation improves survival and body condition of hatchery-reared steelhead (Oncorhynchus mykiss) in Oregon
Early rearing of steelhead (Oncorhynchus mykiss) in Oregon hatcheries is often problematic; fry can become emaciated and die during the period between hatch and first feed. Thiamine (vitamin B1) deficiency has caused early mortality in salmonids; however, the thiamine status of Oregon’s steelhead populations is unknown, to date. Of the 26 egg samples from three Oregon hatcheries in 2019...
Authors
Aimee N. Reed, Freya Elizabeth Rowland, Jennifer A. Krajcik, Donald E. Tillitt
Genetic basis of thiaminase I activity in a vertebrate, zebrafish Danio rerio
Thiamine (vitamin B1) metabolism is an important driver of human and animal health and ecological functioning. Some organisms, including species of ferns, mollusks, and fish, contain thiamine-degrading enzymes known as thiaminases, and consumption of these organisms can lead to thiamine deficiency in the consumer. Consumption of fish containing thiaminase has led to elevated mortality...
Authors
Catherine A. Richter, Allison N. Evans, Scott A. Heppell, James L. Zajicek, Donald E. Tillitt
Comparison of two estrogen chemically activated luciferase expression cell bioassays to liquid chromatography–mass spectrometry for quantifying estrone in water samples
Chemically activated luciferase expression (CALUX) cell bioassays are popular tools for assessing endocrine activity of chemicals such as certain environmental contaminants. Although activity equivalents can be obtained from CALUX analysis, directly comparing these equivalents to those obtained from analytical chemistry methods can be problematic because of the complexity of endocrine...
Authors
Jennifer Brennan, Abigail Henke, Robert W. Gale, Diane Nicks, Donald E. Tillitt
Declines in reproductive condition of male largemouth bass (Micropterus salmoides) following seasonal exposure to estrogenic endocrine-disrupting compounds
Reproductive abnormalities, that could lead to possible effects at the population level, have been observed in wild fish throughout the United States, with high prevalence in largemouth bass (LMB; Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Estrone (E1) and atrazine (ATR) are common environmental contaminants often associated with agricultural land use. 17alpha...
Authors
Jessica Kristin Leet, Catherine A. Richter, Robert W. Gale, Donald E. Tillitt, Jill A. Jenkins
Exposure to 17α-ethinylestradiol results in differential susceptibility of largemouth bass (Micropterus salmoides) to bacterial infection
Disease outbreaks, skin lesions, mortality events, and reproductive abnormalities have been observed in wild populations of centrarchids. The presence of estrogenic endocrine disrupting compounds (EEDCs) has been implicated as a potential causal factor for these effects. The effects of prior EEDC exposure on immune response were examined in juvenile largemouth bass (Micropterus salmoides...
Authors
Jessica Kristin Leet, Justin Blaine Greer, Catherine A. Richter, Luke Iwanowicz, Edward Spinard, Jacquelyn McDonald, Carla M. Conway, Robert W. Gale, Donald E. Tillitt, John D. Hansen
Response to Gard et al.'s (2021) Comments on the Critical Review “Polychlorinated Biphenyl Tissue-Concentration Thresholds for Survival, Growth, and Reproduction in Fish”
This response is offered to the critique by Gard et al. (2021) of our meta-analysis of polychlorinated biphenyl (PCB)-induced toxicity data in fish (Berninger and Tillitt 2019). Gard et al. (2021) offered numerous comments, the most substantive suggesting that 1) we should have added no-observable–adverse effect residue (NOAER) data from additional studies and all data points from...
Authors
Jason P. Berninger, Donald E. Tillitt
Reproduction
Lake charr Salvelinus namaycush are typically fall spawners although one ecotype has populations that spawn during spring and fall (siscowets in Lake Superior). Lake charr are iteroparous (reproduce more than once in a lifetime) with group-synchronous ovarian development and typically spawn once per year. However, lake charr may not reproduce every year, a phenomenon known as skipped...
Authors
Frederick W. Goetz, J. Ellen Marsden, Catherine A. Richter, Donald E. Tillitt, Shawn P. Sitar, Stephen Riley, Charles C. Krueger
*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