Hydroacoustic systems have been used for . 30 yr to survey aquatic plant communities. The objecti... more Hydroacoustic systems have been used for . 30 yr to survey aquatic plant communities. The objective of this study was to collect and analyze data using two commonly available but different hydroacoustic systems to determine whether both sets of gear yielded similar estimates of aquatic plant abundance and height statistics. There were appreciable differences in the estimates of submerged macrophyte abundance, plant height, and variability in plant height estimated from data collected with a Lowrance HDS transducer and processed with BioBase compared with data collected with a BioSonics transducer and processed with Echoview. Both approaches produced estimates of plant abundance that deviated from plant community observations. Compared with the those plant community observations and the BioSonics/Echoview system, the Lowrance/BioBase system produced higher estimates of plant height by depth stratum with higher variability, likely because of lower occurrences of registered aquatic pla...
Age-0 lake trout are distributed heterogeneously on and near spawning shoals, but factors have no... more Age-0 lake trout are distributed heterogeneously on and near spawning shoals, but factors have not been evaluated that might explain these patchy distributions. We surveyed two lake trout spawning areas, Gull Island Shoal and Sand Cut Shoals in Lake Superior, to determine the primary variables influencing monthly variability in the spatial distribution of age-0 lake trout. We evaluated the effects of sculpin abundance, mysid abundance, temperature, foraging potential, and bioenergetic growth rate potential using spatially-discrete modeling techniques and compared these models with the distribution of age-0 lake trout determined from trawl data. The most significant variable influencing age-0 lake trout distribution was bioenergetic growth rate potential based on a foraging model that estimated proportion of maximum consumption per minute. A classification tree model based on this variable predicted the presence of age-0 lake trout in trawl data with 82% and 61% accuracy at Gull Isla...
North American Journal of Fisheries Management, 2007
... 2005; Stockwell et al. 2006b) and benthic species. ... We thank Captain Joe Walters, First Ma... more ... 2005; Stockwell et al. 2006b) and benthic species. ... We thank Captain Joe Walters, First Mate Mike McCann, Engineer Keith Peterson, Biological Technicians Lori Evrard and Gary Cholwek, and Lindsey Lesmeister for their experience and professionalism onboard the RV Kiyi. ...
Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled... more Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled to be biologically meaningful. In this study, we used a general model to correlate site-specific hydroacoustic backscatter with zooplankton dry weight biomass estimated ...
Hydroacoustic systems have been used for. 30 yr to survey aquatic plant communities. The objectiv... more Hydroacoustic systems have been used for. 30 yr to survey aquatic plant communities. The objective of this study was to collect and analyze data using two commonly available but different hydroacoustic systems to determine whether both sets of gear yielded similar estimates of aquatic plant abundance and height statistics. There were appreciable differences in the estimates of submerged macrophyte abundance, plant height, and variability in plant height estimated from data collected with a Lowrance HDS transducer and processed with BioBase compared with data collected with a BioSonics transducer and processed with Echoview. Both approaches produced estimates of plant abundance that deviated from plant community observations. Compared with the those plant community observations and the BioSonics/Echoview system, the Low-rance/BioBase system produced higher estimates of plant height by depth stratum with higher variability, likely because of lower occurrences of registered aquatic plants in each depth stratum, and may have overestimated plant heights in shallow waters. In contrast, BioSonics/Echoview produced a higher frequency of submerged macrophyte occurrences at all depths and may have overestimated occurrences in deep water. Differences appeared to be mostly due to the signal processing approaches. Investigators should tailor a system for their specific survey objectives, needed accuracy, and resources. The use of this technology for long-term monitoring will likely require standardization of data collection equipment and signal processing.
Hydroacoustic systems have been used for . 30 yr to survey aquatic plant communities. The objecti... more Hydroacoustic systems have been used for . 30 yr to survey aquatic plant communities. The objective of this study was to collect and analyze data using two commonly available but different hydroacoustic systems to determine whether both sets of gear yielded similar estimates of aquatic plant abundance and height statistics. There were appreciable differences in the estimates of submerged macrophyte abundance, plant height, and variability in plant height estimated from data collected with a Lowrance HDS transducer and processed with BioBase compared with data collected with a BioSonics transducer and processed with Echoview. Both approaches produced estimates of plant abundance that deviated from plant community observations. Compared with the those plant community observations and the BioSonics/Echoview system, the Lowrance/BioBase system produced higher estimates of plant height by depth stratum with higher variability, likely because of lower occurrences of registered aquatic pla...
Age-0 lake trout are distributed heterogeneously on and near spawning shoals, but factors have no... more Age-0 lake trout are distributed heterogeneously on and near spawning shoals, but factors have not been evaluated that might explain these patchy distributions. We surveyed two lake trout spawning areas, Gull Island Shoal and Sand Cut Shoals in Lake Superior, to determine the primary variables influencing monthly variability in the spatial distribution of age-0 lake trout. We evaluated the effects of sculpin abundance, mysid abundance, temperature, foraging potential, and bioenergetic growth rate potential using spatially-discrete modeling techniques and compared these models with the distribution of age-0 lake trout determined from trawl data. The most significant variable influencing age-0 lake trout distribution was bioenergetic growth rate potential based on a foraging model that estimated proportion of maximum consumption per minute. A classification tree model based on this variable predicted the presence of age-0 lake trout in trawl data with 82% and 61% accuracy at Gull Isla...
North American Journal of Fisheries Management, 2007
... 2005; Stockwell et al. 2006b) and benthic species. ... We thank Captain Joe Walters, First Ma... more ... 2005; Stockwell et al. 2006b) and benthic species. ... We thank Captain Joe Walters, First Mate Mike McCann, Engineer Keith Peterson, Biological Technicians Lori Evrard and Gary Cholwek, and Lindsey Lesmeister for their experience and professionalism onboard the RV Kiyi. ...
Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled... more Hydroacoustics can be used to assess zooplankton populations, however, backscatter must be scaled to be biologically meaningful. In this study, we used a general model to correlate site-specific hydroacoustic backscatter with zooplankton dry weight biomass estimated ...
Hydroacoustic systems have been used for. 30 yr to survey aquatic plant communities. The objectiv... more Hydroacoustic systems have been used for. 30 yr to survey aquatic plant communities. The objective of this study was to collect and analyze data using two commonly available but different hydroacoustic systems to determine whether both sets of gear yielded similar estimates of aquatic plant abundance and height statistics. There were appreciable differences in the estimates of submerged macrophyte abundance, plant height, and variability in plant height estimated from data collected with a Lowrance HDS transducer and processed with BioBase compared with data collected with a BioSonics transducer and processed with Echoview. Both approaches produced estimates of plant abundance that deviated from plant community observations. Compared with the those plant community observations and the BioSonics/Echoview system, the Low-rance/BioBase system produced higher estimates of plant height by depth stratum with higher variability, likely because of lower occurrences of registered aquatic plants in each depth stratum, and may have overestimated plant heights in shallow waters. In contrast, BioSonics/Echoview produced a higher frequency of submerged macrophyte occurrences at all depths and may have overestimated occurrences in deep water. Differences appeared to be mostly due to the signal processing approaches. Investigators should tailor a system for their specific survey objectives, needed accuracy, and resources. The use of this technology for long-term monitoring will likely require standardization of data collection equipment and signal processing.
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Papers by Beth V Holbrook