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Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

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Full-Text Articles in Other Environmental Sciences

Back-Calculated Length-At-Age Estimates From Two Scale Radii, Keith L. Hurley, Kevin L. Pope, David W. Willis Jan 1997

Back-Calculated Length-At-Age Estimates From Two Scale Radii, Keith L. Hurley, Kevin L. Pope, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Variability in length-at-age estimates back-calculated from scales continues to be of concern to fishery scientists. Measurement transects used to back-calculate length at age have been recommended; however, specific scale and annuli radius measurements have not been evaluated for variability between different radii. Thus, the purpose of our study was to compare back-calculated length-at-age estimates determined from two different scale radii: one horizontally from the focus to the anterior-median edge and one diagonally from the focus to the anterior-lateral corner of the scale. No significant differences (P = 0.13 - 0.58 and P = 0.24 - 0.87) in backcalculated length-at-age estimates …

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Effects Of Red Imported Fire Ants On Recruitment Of White-Tailed Deer Fawns, Craig R. Allen, Stephen Demarais, R. Scott Lutz Jan 1997

Effects Of Red Imported Fire Ants On Recruitment Of White-Tailed Deer Fawns, Craig R. Allen, Stephen Demarais, R. Scott Lutz

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We investigated the effect of red imported fire ants (RIFA; Solenopsis invicta) on an index of whitetailed deer (Odocoileus virginianus) fawn recruitment (doe:fawn ratio) on 10 200-ha plots in the Texas Coastal Prairie during 1991-93. Five of the plots received treatments of the fire ant bait AMDRO© (Am. Cyanamid Co., Wayne, N.].) during April and October 1991 and May 1992 to reduce RIFA populations. The remaining 5 plots served as untreated comparison areas. Populations of RIFA were reduced (P < 0.10) on treated study areas during deer fawning periods in 1991-92. Fawn recruitment was higher on treated areas during 1991 (P = 0.037) and 1992 (P = 0.069), with recruitment about twice as high on treated areas. In 1993, after 1 year of RIFA reinfestation, fawn recruitment did not differ between treated and untreated plots (P = 0.443). We conclude that high density RIFA infestations reduced white-tailed deer fawn recruitment.

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Effect Of Red Imported Fire Ant Envenomization On Neonatal American Alligators, Craig R. Allen, Kenneth G. Rice, Daniel P. Wojcik, H. Franklin Percival Jan 1997

Effect Of Red Imported Fire Ant Envenomization On Neonatal American Alligators, Craig R. Allen, Kenneth G. Rice, Daniel P. Wojcik, H. Franklin Percival

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Alligator populations in the southeastern United States have substantially recovered since the late 1960s when they were placed on the federal Endangered Species List (Joanen and McNease, 1987). In Florida, both early age class and adult animals currently are harvested for commercial and recreational purposes (Hines and Abercrombie, 1987). In addition, the alligator is ecologically important as a keystone species and as an indicator of wetland health (Mazzotti and Brandt, 1994). Recently, the nonnative ant Solenopsis invicta (the red imported fire ant) has surfaced as a potential threat to alligator populations. Solenopsis invicta is a relatively new (approx. 65 yr) …

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Environmental Characteristics Of Black Crappie (Pomoxis Nigromaculatus) Nesting Sites In Two South Dakota Waters, K. L. Pope, D. W. Willis Jan 1997

Environmental Characteristics Of Black Crappie (Pomoxis Nigromaculatus) Nesting Sites In Two South Dakota Waters, K. L. Pope, D. W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

A biotelemetry study was undertaken during spring 1995 to identify black crappie (Pomoxis nigromaculatus) nesting sites in two South Dakota water bodies. Individually coded ultrasonic transmitters were implanted into the body cavity of 15 adult male black crappie in each water body prior to spawning. Available habitat characteristics were recorded at 75 randomly selected sites within each water body, and habitat characteristics at nesting sites were recorded for each male black crappie believed to be nesting. Of the habitat characteristics analyzed, only substrate firmness did not differ (P=0.79) between water bodies. In Richmond Lake, black crappie selected nesting …

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Oxytetracycline Marking Efficacy For Yellow Perch Fingerlings And Temporal Assays Of Tissue Residues, Eric G. Unkenholz, Michael L. Brown, Kevin L. Pope Jan 1997

Oxytetracycline Marking Efficacy For Yellow Perch Fingerlings And Temporal Assays Of Tissue Residues, Eric G. Unkenholz, Michael L. Brown, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Differentiating between hatchery and naturally reproduced fishes is difficult because of the lack of appropriate marking techniques. Chemical immersion techniques can be a practical method for mass marking juvenile fishes. The objectives of this study were to determine the concentration of oxytetracycline (OTC) hydrochloride needed to effectively mark age-0 yellow perch Perca flavescens to observe the retention lime of the mark, and to measure the persistence of OTC in body tissues. Fish were immersed in 309, 534, and 748 mg OTC/L for 12 h. Initial fish collections were made weekly, and monthly collections began 1 month postmarking for tissue and …

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An Assessment Of Burbot (Lota Iota) Weight - Length Data From North American Populations, Shannon J. Fisher, David W. Willis, Kevin L. Pope Jan 1996

An Assessment Of Burbot (Lota Iota) Weight - Length Data From North American Populations, Shannon J. Fisher, David W. Willis, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Declining buroot (Lola lola) abundance across some portions of North America has prompted a search for additional evaluation tools, including a measure of condition. Weight - length data were compiled for 10293 burbot from 79 North American populations. These data were used to develop a 75th percentile standard weight (W,) equation using the regression-line-percentile technique. The proposed equation is log10 W3 = - 4.868 + 2.898 log10 TL, where Ws is the standard weight in grams, and TL is the maximum total length in millimetres. The equation is valid for burbot ≥20 cm and …

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Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais Jan 1996

Effects Of Red Imported Fire Ants On Northern Bobwhite Chicks, William M. Giuliano, Craig R. Allen, R. Scott Lutz, Stephen Demarais

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Populations of red imported fire ants (RIFA; Solenopsis invtcta) have spread rapidly throughout the southeastern United States. RIFA, directly or indirectly, negatively affect many wildlife species, and northern bobwhite (Colinus virginianus) appear to be particularly susceptible. We examined the effect of exposure to different numbers of RIFA for 15 and 60 seconds on body mass and survival of captive northern bobwhite chicks. Compared to unexposed birds, survival of chicks was reduced with exposure to as few as 50 RIFA for 60 seconds, or 200 RIFA for 15 seconds, and body mass was lower in chicks exposed to …

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Egg Development In A High-Density Black Crappie (Pomoxis Nigromacuiatus) Population, Kevin L. Pope, Wade T. Geraets, David W. Willis Jan 1996

Egg Development In A High-Density Black Crappie (Pomoxis Nigromacuiatus) Population, Kevin L. Pope, Wade T. Geraets, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Female black crappie (Pomoxis nigromaculatus) were collected from Richmond Lake, South Dakota" and egg-diameter frequencies were examined to document spawning strategy during 1994. Two hundred and sixteen adult females [mean total length (TL) ±SE = 204 ± 1 mm] were collected and 85,572 egg diameters were measured. Female black crappie gonadosomatic-index (GSI) values exceeded 8% from 18 May to 22 June 1994, and the density of larval black crappie caught with an ichthyoplankton net peaked on 8 June 1994. The GSI values and larval catches indicated that the population, as a whole, had a single extended spawn from …

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Seasonal Influences On Freshwater Fisheries Sampling Data, Kevin L. Pope, David W. Willis Jan 1996

Seasonal Influences On Freshwater Fisheries Sampling Data, Kevin L. Pope, David W. Willis

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Fisheries managers often assess fish populations using catch per unit effort (CPUE), size and age structure, growth, and condition. For many freshwater fishes and common sampling gears, CPUE, size and age structure, and condition are highest in the spring and fall, while growth commonly is fastest during the summer growing season. However, there are exceptions to these general trends, especially in populations with erratic recruitment, growth, or mortality. At the least, CPUE, size and age structure, growth, and condition of fish should be expected to change with season, given the effects of variable recruitment, growth, and mortality. However, if recruitment, …

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Red Imported Fire Ant Impact On Wildlife: An Overview, Craig R. Allen, Stephen Demarais, R. Scott Lutz Jan 1994

Red Imported Fire Ant Impact On Wildlife: An Overview, Craig R. Allen, Stephen Demarais, R. Scott Lutz

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We reviewed the past 50 years of literature concerning red imported fire ant impacts on wildlife species. The red imported fire ant has had a negative impact on numerous species of wildlife. However, experimental evidence of population-level impacts is meager. We discuss potential fire ant perturbations and suggest research directions that may settle the long-standing controversy concerning the impact of imported fire ants on native vertebrates and the ecosystems they have invaded.

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Interactions Between Larval White Crappie And Gizzard Shad: Quantifying Mechanisms In Small Ponds, Kevin L. Pope, Dennis R. Devries Jan 1994

Interactions Between Larval White Crappie And Gizzard Shad: Quantifying Mechanisms In Small Ponds, Kevin L. Pope, Dennis R. Devries

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

To test potential competitive interactions between larvae of white crappie Pomoxis annularis and of gizzard shad Dorosoma cepedianum. we added adult gizzard shad to eight of twelve 0.1-ha ponds that had been stocked with adult white crappies. Larval white crappies and larval gizzard shad appeared within 1 week of one another and larval white crappie density did not differ between treatments. Zooplankton density declined similarly between treatments, and zooplankton species composition and size did not differ. Although larval white crappie and larval gizzard shad had moderate diet overlap, prey selection by white crappie did not differ between treatments. During …

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