Brent Knights (Former Employee)
Science and Products
Filter Total Items: 50
USGS geospatial support for unified fishing method USGS geospatial support for unified fishing method
No abstract available.
Authors
Kevin D. Hop, Andrew C. Strassman, Jonathan M. Vallazza, Brent C. Knights
Evaluating potential effects of bigheaded carps on fatty acid profiles of multiple trophic levels in large rivers of the Midwest, USA Evaluating potential effects of bigheaded carps on fatty acid profiles of multiple trophic levels in large rivers of the Midwest, USA
Recent work indicates that the establishment of bigheaded carps (Hypophthalmichthys spp.) in the United States has led to a reduction in condition of native planktivores and may detrimentally affect other trophic levels by altering the base of aquatic food webs. We used fatty acids to evaluate potential effects of bigheaded carps on taxa from multiple trophic levels in the Upper...
Authors
Andrea K. Fritts, Brent C. Knights, Toben LaFrancois, Jonathan M. Vallazza, Lynn A. Bartsch, Michelle R. Bartsch, William B. Richardson, Sean Bailey, Rebecca M. Kreiling, Byron Karns
Stable isotope comparison between mantle and foot tissues of two freshwater unionids: Implications for food web studies Stable isotope comparison between mantle and foot tissues of two freshwater unionids: Implications for food web studies
Unionid mussels are a key taxon for stable isotope studies of aquatic food webs, often serving as the primary integrator of the pelagic baseline. Past isotope studies with mussels have commonly used either foot tissue or mantle tissue, but no study has yet to quantify the relation of both carbon and nitrogen isotopes between these two tissue sources. This makes it difficult to justify...
Authors
Toben LaFrancois, Andrea K. Fritts, Brent C. Knights, Byron Karns
Spatial and temporal variance in fatty acid and stable isotope signatures across trophic levels in large river systems Spatial and temporal variance in fatty acid and stable isotope signatures across trophic levels in large river systems
Fatty acid and stable isotope signatures allow researchers to better understand food webs, food sources, and trophic relationships. Research in marine and lentic systems has indicated that the variance of these biomarkers can exhibit substantial differences across spatial and temporal scales, but this type of analysis has not been completed for large river systems. Our objectives were to...
Authors
Andrea K. Fritts, Brent C. Knights, Toben D. Lafrancois, Lynn A. Bartsch, Jonathan M. Vallazza, Michelle R. Bartsch, William B. Richardson, Byron N. Karns, Sean Bailey, Rebecca M. Kreiling
Using pharyngeal teeth and chewing pads to estimate juvenile Silver Carp total length in the La Grange Reach, Illinois River Using pharyngeal teeth and chewing pads to estimate juvenile Silver Carp total length in the La Grange Reach, Illinois River
The Silver Carp Hypophthalmichthys molitrix is an invasive species in the Mississippi River basin; an understanding of their vulnerability to predation as juveniles may inform control by native predators and predator enhancement (e.g., stocking). Digestion of Silver Carp prey recovered from diets makes it difficult to determine the size‐classes that are most vulnerable to predation by...
Authors
Eli G. Lampo, Brent C. Knights, Jonathan M. Vallazza, Cory A. Anderson, Will T. Rechkemmer, Levi E. Solomon, Andrew F. Casper, Richard M. Pendleton, James T. Lamer
Evidence of Asian carp spawning upstream of a key choke point in the Mississippi River Evidence of Asian carp spawning upstream of a key choke point in the Mississippi River
Bighead Carp Hypophthalmichthys nobilis, Silver Carp H. molitrix, and Grass Carp Ctenopharyngodon idella(collectively termed “Asian carp”) were introduced into North America during the 1960s and 1970s and have become established in the lower Mississippi River basin. Previously published evidence for spawning of these species in the upper Mississippi River has been limited to an area just
Authors
James H. Larson, Brent C. Knights, S. Grace McCalla, Emy Monroe, Maren T. Tuttle-Lau, Duane Chapman, Amy E. George, Jonathan M. Vallazza, Jon Amberg
Science and Products
Filter Total Items: 50
USGS geospatial support for unified fishing method USGS geospatial support for unified fishing method
No abstract available.
Authors
Kevin D. Hop, Andrew C. Strassman, Jonathan M. Vallazza, Brent C. Knights
Evaluating potential effects of bigheaded carps on fatty acid profiles of multiple trophic levels in large rivers of the Midwest, USA Evaluating potential effects of bigheaded carps on fatty acid profiles of multiple trophic levels in large rivers of the Midwest, USA
Recent work indicates that the establishment of bigheaded carps (Hypophthalmichthys spp.) in the United States has led to a reduction in condition of native planktivores and may detrimentally affect other trophic levels by altering the base of aquatic food webs. We used fatty acids to evaluate potential effects of bigheaded carps on taxa from multiple trophic levels in the Upper...
Authors
Andrea K. Fritts, Brent C. Knights, Toben LaFrancois, Jonathan M. Vallazza, Lynn A. Bartsch, Michelle R. Bartsch, William B. Richardson, Sean Bailey, Rebecca M. Kreiling, Byron Karns
Stable isotope comparison between mantle and foot tissues of two freshwater unionids: Implications for food web studies Stable isotope comparison between mantle and foot tissues of two freshwater unionids: Implications for food web studies
Unionid mussels are a key taxon for stable isotope studies of aquatic food webs, often serving as the primary integrator of the pelagic baseline. Past isotope studies with mussels have commonly used either foot tissue or mantle tissue, but no study has yet to quantify the relation of both carbon and nitrogen isotopes between these two tissue sources. This makes it difficult to justify...
Authors
Toben LaFrancois, Andrea K. Fritts, Brent C. Knights, Byron Karns
Spatial and temporal variance in fatty acid and stable isotope signatures across trophic levels in large river systems Spatial and temporal variance in fatty acid and stable isotope signatures across trophic levels in large river systems
Fatty acid and stable isotope signatures allow researchers to better understand food webs, food sources, and trophic relationships. Research in marine and lentic systems has indicated that the variance of these biomarkers can exhibit substantial differences across spatial and temporal scales, but this type of analysis has not been completed for large river systems. Our objectives were to...
Authors
Andrea K. Fritts, Brent C. Knights, Toben D. Lafrancois, Lynn A. Bartsch, Jonathan M. Vallazza, Michelle R. Bartsch, William B. Richardson, Byron N. Karns, Sean Bailey, Rebecca M. Kreiling
Using pharyngeal teeth and chewing pads to estimate juvenile Silver Carp total length in the La Grange Reach, Illinois River Using pharyngeal teeth and chewing pads to estimate juvenile Silver Carp total length in the La Grange Reach, Illinois River
The Silver Carp Hypophthalmichthys molitrix is an invasive species in the Mississippi River basin; an understanding of their vulnerability to predation as juveniles may inform control by native predators and predator enhancement (e.g., stocking). Digestion of Silver Carp prey recovered from diets makes it difficult to determine the size‐classes that are most vulnerable to predation by...
Authors
Eli G. Lampo, Brent C. Knights, Jonathan M. Vallazza, Cory A. Anderson, Will T. Rechkemmer, Levi E. Solomon, Andrew F. Casper, Richard M. Pendleton, James T. Lamer
Evidence of Asian carp spawning upstream of a key choke point in the Mississippi River Evidence of Asian carp spawning upstream of a key choke point in the Mississippi River
Bighead Carp Hypophthalmichthys nobilis, Silver Carp H. molitrix, and Grass Carp Ctenopharyngodon idella(collectively termed “Asian carp”) were introduced into North America during the 1960s and 1970s and have become established in the lower Mississippi River basin. Previously published evidence for spawning of these species in the upper Mississippi River has been limited to an area just
Authors
James H. Larson, Brent C. Knights, S. Grace McCalla, Emy Monroe, Maren T. Tuttle-Lau, Duane Chapman, Amy E. George, Jonathan M. Vallazza, Jon Amberg