David Ward (Former Employee)
Science and Products
Filter Total Items: 32
Effects of water temperature and fish size on predation vulnerability of juvenile humpback chub to rainbow trout and brown trout Effects of water temperature and fish size on predation vulnerability of juvenile humpback chub to rainbow trout and brown trout
Predation on juvenile native fish by introduced Rainbow Trout and Brown Trout is considered a significant threat to the persistence of endangered Humpback Chub Gila cypha in the Colorado River in the Grand Canyon. Diet studies of Rainbow Trout and Brown Trout in Glen and Grand canyons indicate that these species do eat native fish, but impacts are difficult to assess because predation
Authors
David L. Ward, Rylan Morton-Starner
A laboratory evaluation of tagging-related mortality and tag loss in juvenile humpback chub A laboratory evaluation of tagging-related mortality and tag loss in juvenile humpback chub
We quantified tag retention, survival, and growth in juvenile, captive-reared Humpback Chub Gila cypha marked with three different tag types: (1) Biomark 12.5-mm, 134.2-kHz, full duplex PIT tags injected into the body cavity with a 12-gauge needle; (2) Biomark 8.4-mm, 134.2-kHz, full duplex PIT tags injected with a 16-gauge needle; and (3) Northwest Marine Technology visible implant...
Authors
David L. Ward, William R. Persons, Kirk Young, Dennis M. Stone, Randy Van Haverbeke, William R. Knight
Effectiveness of backpack electrofishing for removal of non-native fishes from a small warm-water stream Effectiveness of backpack electrofishing for removal of non-native fishes from a small warm-water stream
Electrofishing is commonly used when renovating small streams to remove nuisance fishes but the likelihood of complete eradication of unwanted species, particularly warm-water fishes, is unknown. In October of 2008, we electrofished Bonita Creek, a small stream with base flows (
Authors
David L. Ward, Matthew W. O’neill, Cassie Ka’apu-Lyons
Could high salinity be used to control bullfrogs in small ponds? Could high salinity be used to control bullfrogs in small ponds?
We examined survival of bullfrog (Rana catesbeiana) eggs and tadpoles at 3 ppt and 6 ppt salinity in the laboratory to determine if low-level salinity could be used to eradicate bullfrogs from small ponds that contain native fishes. Bullfrog eggs and tadpoles 9 months old) appeared unaffected by 14 days of 6 ppt salinity. Salinity of 3 ppt did not impact survival of bullfrog tadpole eggs...
Authors
David L. Ward, Colton Finch, Heidi Blasius
Behaviors of southwestern native fishes in response to introduced catfish predators Behaviors of southwestern native fishes in response to introduced catfish predators
Native fishes reared in hatcheries typically suffer high predation mortality when stocked into natural environments. We evaluated the behavior of juvenile bonytail Gila elegans, roundtail chub Gila robusta, razorback sucker Xyrauchen texanus, and Sonora sucker Catostomus insignis in response to introduced channel catfish Ictalurus punctatus and flathead catfish Pylodictis olivaris. Our...
Authors
David L. Ward, Chester R. Figiel
An evaluation of liquid ammonia (ammonium hydroxide) as a candidate piscicide An evaluation of liquid ammonia (ammonium hydroxide) as a candidate piscicide
Eradication of populations of nonnative aquatic species for the purpose of reintroducing native fish is often difficult because very few effective tools are available for removing aquatic organisms. This creates the need to evaluate new chemicals that could be used as management tools for native fish conservation. Ammonia is a natural product of fish metabolism and is naturally present...
Authors
David L. Ward, R. Morton-Starner, Shaula J. Hedwall
Science and Products
Filter Total Items: 32
Effects of water temperature and fish size on predation vulnerability of juvenile humpback chub to rainbow trout and brown trout Effects of water temperature and fish size on predation vulnerability of juvenile humpback chub to rainbow trout and brown trout
Predation on juvenile native fish by introduced Rainbow Trout and Brown Trout is considered a significant threat to the persistence of endangered Humpback Chub Gila cypha in the Colorado River in the Grand Canyon. Diet studies of Rainbow Trout and Brown Trout in Glen and Grand canyons indicate that these species do eat native fish, but impacts are difficult to assess because predation
Authors
David L. Ward, Rylan Morton-Starner
A laboratory evaluation of tagging-related mortality and tag loss in juvenile humpback chub A laboratory evaluation of tagging-related mortality and tag loss in juvenile humpback chub
We quantified tag retention, survival, and growth in juvenile, captive-reared Humpback Chub Gila cypha marked with three different tag types: (1) Biomark 12.5-mm, 134.2-kHz, full duplex PIT tags injected into the body cavity with a 12-gauge needle; (2) Biomark 8.4-mm, 134.2-kHz, full duplex PIT tags injected with a 16-gauge needle; and (3) Northwest Marine Technology visible implant...
Authors
David L. Ward, William R. Persons, Kirk Young, Dennis M. Stone, Randy Van Haverbeke, William R. Knight
Effectiveness of backpack electrofishing for removal of non-native fishes from a small warm-water stream Effectiveness of backpack electrofishing for removal of non-native fishes from a small warm-water stream
Electrofishing is commonly used when renovating small streams to remove nuisance fishes but the likelihood of complete eradication of unwanted species, particularly warm-water fishes, is unknown. In October of 2008, we electrofished Bonita Creek, a small stream with base flows (
Authors
David L. Ward, Matthew W. O’neill, Cassie Ka’apu-Lyons
Could high salinity be used to control bullfrogs in small ponds? Could high salinity be used to control bullfrogs in small ponds?
We examined survival of bullfrog (Rana catesbeiana) eggs and tadpoles at 3 ppt and 6 ppt salinity in the laboratory to determine if low-level salinity could be used to eradicate bullfrogs from small ponds that contain native fishes. Bullfrog eggs and tadpoles 9 months old) appeared unaffected by 14 days of 6 ppt salinity. Salinity of 3 ppt did not impact survival of bullfrog tadpole eggs...
Authors
David L. Ward, Colton Finch, Heidi Blasius
Behaviors of southwestern native fishes in response to introduced catfish predators Behaviors of southwestern native fishes in response to introduced catfish predators
Native fishes reared in hatcheries typically suffer high predation mortality when stocked into natural environments. We evaluated the behavior of juvenile bonytail Gila elegans, roundtail chub Gila robusta, razorback sucker Xyrauchen texanus, and Sonora sucker Catostomus insignis in response to introduced channel catfish Ictalurus punctatus and flathead catfish Pylodictis olivaris. Our...
Authors
David L. Ward, Chester R. Figiel
An evaluation of liquid ammonia (ammonium hydroxide) as a candidate piscicide An evaluation of liquid ammonia (ammonium hydroxide) as a candidate piscicide
Eradication of populations of nonnative aquatic species for the purpose of reintroducing native fish is often difficult because very few effective tools are available for removing aquatic organisms. This creates the need to evaluate new chemicals that could be used as management tools for native fish conservation. Ammonia is a natural product of fish metabolism and is naturally present...
Authors
David L. Ward, R. Morton-Starner, Shaula J. Hedwall