David Ward (Former Employee)
Science and Products
Filter Total Items: 32
Standardized methods for Grand Canyon fisheries research 2015 Standardized methods for Grand Canyon fisheries research 2015
This document presents protocols and guidelines to persons sampling fishes in the Grand Canyon, to help ensure consistency in fish handling, fish tagging, and data collection among different projects and organizations. Most such research and monitoring projects are conducted under the general umbrella of the Glen Canyon Dam Adaptive Management Program and include studies by the U.S...
Authors
William R. Persons, David L. Ward, Luke A. Avery
Salinity of the Little Colorado River in Grand Canyon confers anti-parasitic properties on a native fish Salinity of the Little Colorado River in Grand Canyon confers anti-parasitic properties on a native fish
Water in the Little Colorado River within Grand Canyon is naturally high in salt (NaCl), which is known to prohibit development of external fish parasites such as Ich (Ichthyophthirius multifiliis). The naturally high salinity (>0.3%) of the Little Colorado River at baseflow may be one factor allowing survival and persistence of larval and juvenile humpback chub (Gila cypha) and other...
Authors
David L. Ward
Effects of capture by trammel net on Colorado River native fishes Effects of capture by trammel net on Colorado River native fishes
Trammel nets are commonly used to sample rare fishes; however, little research has assessed delayed mortality associated with this capture technique. We conducted laboratory experiments to evaluate the effects of capture by trammel net on bonytail Gila elegans, razorback sucker Xyrauchen texanus, and roundtail chub Gila robusta, at 15, 20, and 25uC. Fish (139–288 mm total length) were...
Authors
Teresa A. Hunt, David L. Ward, Catherine R. Propper, Alice C. Gibb
Relationship between fish size and upper thermal tolerance Relationship between fish size and upper thermal tolerance
Using critical thermal maximum (CTMax) tests, we examined the relationship between upper temperature tolerances and fish size (fry-adult or subadult lengths) of rainbow trout Oncorhynchus mykiss (41-200-mm TL), Apache trout O. gilae apache (40-220-mm TL), largemouth bass Micropterus salmoides (72-266-mm TL), Nile tilapia Oreochromis niloticus (35-206-mm TL), channel catfish Ictalurus...
Authors
Matthew S. Recsetar, Matthew P. Zeigler, David L. Ward, Scott A. Bonar, Colleen A. Caldwell
Abundance trends and status of the Little Colorado River population of humpback chub Abundance trends and status of the Little Colorado River population of humpback chub
The abundance of the Little Colorado River population of federally listed humpback chub Gila cypha in Grand Canyon has been monitored since the late 1980s by means of catch rate indices and capture-recapture-based abundance estimators. Analyses of data from all sources using various methods are consistent and indicate that the adult population has declined since monitoring began...
Authors
L.G. Coggins, William E. Pine, C.J. Walters, D. R. Van Haverbeke, David Ward, H.C. Johnstone
White sturgeon mitigation and restoration in the Columbia and Snake Rivers upstream from Bonneville Dam White sturgeon mitigation and restoration in the Columbia and Snake Rivers upstream from Bonneville Dam
No abstract available
Authors
M.J. Parsley, D.G. Gallion, K.M. Kappenman, P.E. Kofoot
Index of predation on juvenile salmonids by northern squawfish in the lower and middle Columbia River and in the lower Snake River Index of predation on juvenile salmonids by northern squawfish in the lower and middle Columbia River and in the lower Snake River
We developed a predation index to describe the relative magnitude of predation on juvenile salmonids by northern squawfish Ptychocheilus oregonensis throughout the lower and middle Columbia River and lower Snake River. The predation index was the product of an abundance index and a consumption index. We evaluated various catch indices and found that catch per unit effort best reflected...
Authors
David L. Ward, James H. Petersen, John J. Loch
Spatial and temporal variation in proportional stock density and relative weight of smallmouth bass in a reservoir Spatial and temporal variation in proportional stock density and relative weight of smallmouth bass in a reservoir
Population data for smallmouth bass Micropterus dolomieui in 20,235 ha John Day Reservoir on the Columbia River were used to (1) determine whether Proportional Stock Density (PSD) and Relative Weight (Wr) varied spatially and temporally in two areas of the reservoir with established smallmouth bass fisheries; (2) explore possible causes of any observed variation; and (3) discuss some...
Authors
Matthew G. Mesa, S.D. Duke, David L. Ward
Science and Products
Filter Total Items: 32
Standardized methods for Grand Canyon fisheries research 2015 Standardized methods for Grand Canyon fisheries research 2015
This document presents protocols and guidelines to persons sampling fishes in the Grand Canyon, to help ensure consistency in fish handling, fish tagging, and data collection among different projects and organizations. Most such research and monitoring projects are conducted under the general umbrella of the Glen Canyon Dam Adaptive Management Program and include studies by the U.S...
Authors
William R. Persons, David L. Ward, Luke A. Avery
Salinity of the Little Colorado River in Grand Canyon confers anti-parasitic properties on a native fish Salinity of the Little Colorado River in Grand Canyon confers anti-parasitic properties on a native fish
Water in the Little Colorado River within Grand Canyon is naturally high in salt (NaCl), which is known to prohibit development of external fish parasites such as Ich (Ichthyophthirius multifiliis). The naturally high salinity (>0.3%) of the Little Colorado River at baseflow may be one factor allowing survival and persistence of larval and juvenile humpback chub (Gila cypha) and other...
Authors
David L. Ward
Effects of capture by trammel net on Colorado River native fishes Effects of capture by trammel net on Colorado River native fishes
Trammel nets are commonly used to sample rare fishes; however, little research has assessed delayed mortality associated with this capture technique. We conducted laboratory experiments to evaluate the effects of capture by trammel net on bonytail Gila elegans, razorback sucker Xyrauchen texanus, and roundtail chub Gila robusta, at 15, 20, and 25uC. Fish (139–288 mm total length) were...
Authors
Teresa A. Hunt, David L. Ward, Catherine R. Propper, Alice C. Gibb
Relationship between fish size and upper thermal tolerance Relationship between fish size and upper thermal tolerance
Using critical thermal maximum (CTMax) tests, we examined the relationship between upper temperature tolerances and fish size (fry-adult or subadult lengths) of rainbow trout Oncorhynchus mykiss (41-200-mm TL), Apache trout O. gilae apache (40-220-mm TL), largemouth bass Micropterus salmoides (72-266-mm TL), Nile tilapia Oreochromis niloticus (35-206-mm TL), channel catfish Ictalurus...
Authors
Matthew S. Recsetar, Matthew P. Zeigler, David L. Ward, Scott A. Bonar, Colleen A. Caldwell
Abundance trends and status of the Little Colorado River population of humpback chub Abundance trends and status of the Little Colorado River population of humpback chub
The abundance of the Little Colorado River population of federally listed humpback chub Gila cypha in Grand Canyon has been monitored since the late 1980s by means of catch rate indices and capture-recapture-based abundance estimators. Analyses of data from all sources using various methods are consistent and indicate that the adult population has declined since monitoring began...
Authors
L.G. Coggins, William E. Pine, C.J. Walters, D. R. Van Haverbeke, David Ward, H.C. Johnstone
White sturgeon mitigation and restoration in the Columbia and Snake Rivers upstream from Bonneville Dam White sturgeon mitigation and restoration in the Columbia and Snake Rivers upstream from Bonneville Dam
No abstract available
Authors
M.J. Parsley, D.G. Gallion, K.M. Kappenman, P.E. Kofoot
Index of predation on juvenile salmonids by northern squawfish in the lower and middle Columbia River and in the lower Snake River Index of predation on juvenile salmonids by northern squawfish in the lower and middle Columbia River and in the lower Snake River
We developed a predation index to describe the relative magnitude of predation on juvenile salmonids by northern squawfish Ptychocheilus oregonensis throughout the lower and middle Columbia River and lower Snake River. The predation index was the product of an abundance index and a consumption index. We evaluated various catch indices and found that catch per unit effort best reflected...
Authors
David L. Ward, James H. Petersen, John J. Loch
Spatial and temporal variation in proportional stock density and relative weight of smallmouth bass in a reservoir Spatial and temporal variation in proportional stock density and relative weight of smallmouth bass in a reservoir
Population data for smallmouth bass Micropterus dolomieui in 20,235 ha John Day Reservoir on the Columbia River were used to (1) determine whether Proportional Stock Density (PSD) and Relative Weight (Wr) varied spatially and temporally in two areas of the reservoir with established smallmouth bass fisheries; (2) explore possible causes of any observed variation; and (3) discuss some...
Authors
Matthew G. Mesa, S.D. Duke, David L. Ward