David M Warner, PhD (Former Employee)
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Filter Total Items: 53
Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data
Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined...
Authors
Patrick M. Kocovsky, Lars G. Rudstam, Daniel L. Yule, David M. Warner, Ted Schaner, Bernie Pientka, John W. Deller, Holly A. Waterfield, Larry D. Witzel, Patrick J. Sullivan
Changing ecosystem dynamics in the Laurentian Great Lakes: Bottom-up and top-down regulation Changing ecosystem dynamics in the Laurentian Great Lakes: Bottom-up and top-down regulation
Understanding the relative importance of top-down and bottom-up regulation of ecosystem structure is a fundamental ecological question, with implications for fisheries and water-quality management. For the Laurentian Great Lakes, where, since the early 1970s, nutrient inputs have been reduced, whereas top-predator biomass has increased, we describe trends across multiple trophic levels...
Authors
David B. Bunnell, Richard P Barbiero, Stuart A Ludsin, Charles P. Madenjian, Glenn J. Warren, David M. Dolan, Travis O. Brenden, Ruth Briland, Owen T. Gorman, Ji X. Hi, Thomas F. Johengen, Brian F. Lantry, Barry M. Lesht, Thomas F. Nalepa, Stephen C. Riley, Catherine M. Riseng, Ted J. Treska, Iyob Tsehaye, Maureen Walsh, David M. Warner, Brian Weidel
Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities
Pelagic fish assessments often combine large amounts of acoustic-based fish density data and limited midwater trawl information to estimate species-specific biomass density. We compared the accuracy of five apportionment methods for estimating pelagic fish biomass density using simulated communities with known fish numbers that mimic Lakes Superior, Michigan, and Ontario, representing a...
Authors
Daniel L. Yule, Jean V. Adams, David M. Warner, Thomas R. Hrabik, Patrick M. Kocovsky, Brian Weidel, Lars G. Rudstam, Patrick J. Sullivan
Chinook salmon foraging patterns in a changing Lake Michigan Chinook salmon foraging patterns in a changing Lake Michigan
Since Pacific salmon stocking began in Lake Michigan, managers have attempted to maintain salmon abundance at high levels within what can be sustained by available prey fishes, primarily Alewife Alosa pseudoharengus. Chinook Salmon Oncorhynchus tshawytscha are the primary apex predators in pelagic Lake Michigan and patterns in their prey selection (by species and size) may strongly...
Authors
Gregory R. Jacobs, Charles P. Madenjian, David B. Bunnell, David M. Warner, Randall M. Claramunt
Status and trends of pelagic prey fishes in Lake Huron, 2012 Status and trends of pelagic prey fishes in Lake Huron, 2012
The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of...
Authors
David M. Warner, Timothy P. O’Brien, Steve A. Farha, Jeff Schaeffer, Stephen Lenart
Status and trends of pelagic prey fishes in Lake Huron, 2012 Status and trends of pelagic prey fishes in Lake Huron, 2012
The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of...
Authors
David M. Warner, Timothy P. O’Brien, Steve A. Farha, Jeff Schaeffer, Stephen Lenart
Non-USGS Publications**
Warner, D.M., Rudstam, L.G., and Klumb, R.A. 2002. In situ target strength of alewives in freshwater. Trans. Am. Fish. Soc. 131:212-223.
**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.
Science and Products
Data releases by this scientist
Multimedia related to this scientist
Publications by this scientist
Filter Total Items: 53
Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data
Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined...
Authors
Patrick M. Kocovsky, Lars G. Rudstam, Daniel L. Yule, David M. Warner, Ted Schaner, Bernie Pientka, John W. Deller, Holly A. Waterfield, Larry D. Witzel, Patrick J. Sullivan
Changing ecosystem dynamics in the Laurentian Great Lakes: Bottom-up and top-down regulation Changing ecosystem dynamics in the Laurentian Great Lakes: Bottom-up and top-down regulation
Understanding the relative importance of top-down and bottom-up regulation of ecosystem structure is a fundamental ecological question, with implications for fisheries and water-quality management. For the Laurentian Great Lakes, where, since the early 1970s, nutrient inputs have been reduced, whereas top-predator biomass has increased, we describe trends across multiple trophic levels...
Authors
David B. Bunnell, Richard P Barbiero, Stuart A Ludsin, Charles P. Madenjian, Glenn J. Warren, David M. Dolan, Travis O. Brenden, Ruth Briland, Owen T. Gorman, Ji X. Hi, Thomas F. Johengen, Brian F. Lantry, Barry M. Lesht, Thomas F. Nalepa, Stephen C. Riley, Catherine M. Riseng, Ted J. Treska, Iyob Tsehaye, Maureen Walsh, David M. Warner, Brian Weidel
Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities
Pelagic fish assessments often combine large amounts of acoustic-based fish density data and limited midwater trawl information to estimate species-specific biomass density. We compared the accuracy of five apportionment methods for estimating pelagic fish biomass density using simulated communities with known fish numbers that mimic Lakes Superior, Michigan, and Ontario, representing a...
Authors
Daniel L. Yule, Jean V. Adams, David M. Warner, Thomas R. Hrabik, Patrick M. Kocovsky, Brian Weidel, Lars G. Rudstam, Patrick J. Sullivan
Chinook salmon foraging patterns in a changing Lake Michigan Chinook salmon foraging patterns in a changing Lake Michigan
Since Pacific salmon stocking began in Lake Michigan, managers have attempted to maintain salmon abundance at high levels within what can be sustained by available prey fishes, primarily Alewife Alosa pseudoharengus. Chinook Salmon Oncorhynchus tshawytscha are the primary apex predators in pelagic Lake Michigan and patterns in their prey selection (by species and size) may strongly...
Authors
Gregory R. Jacobs, Charles P. Madenjian, David B. Bunnell, David M. Warner, Randall M. Claramunt
Status and trends of pelagic prey fishes in Lake Huron, 2012 Status and trends of pelagic prey fishes in Lake Huron, 2012
The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of...
Authors
David M. Warner, Timothy P. O’Brien, Steve A. Farha, Jeff Schaeffer, Stephen Lenart
Status and trends of pelagic prey fishes in Lake Huron, 2012 Status and trends of pelagic prey fishes in Lake Huron, 2012
The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in 2012 compared to 2011, with density in 2012 only 34% of...
Authors
David M. Warner, Timothy P. O’Brien, Steve A. Farha, Jeff Schaeffer, Stephen Lenart
Non-USGS Publications**
Warner, D.M., Rudstam, L.G., and Klumb, R.A. 2002. In situ target strength of alewives in freshwater. Trans. Am. Fish. Soc. 131:212-223.
**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.