Steffensen K.D.,Nebraska Game and Parks Commission |
Powell L.A.,University of Nebraska - Lincoln
North American Journal of Fisheries Management | Year: 2010
The population of pallid sturgeon Scaphirhynchus albus in the lower Missouri River between Gavins Point Dam (river kilometer [rkm] 1,305.2) and the confluence with the Mississippi River (rkm 0.0) remains imperiled, little to no natural recruitment occurring. Artificial propagation and subsequent population augmentation (i.e., stocking) may be the only viable option for maintaining pallid sturgeon populations in the lower Missouri River in the near term. Because relatively little is known about the ability of hatchery-reared pallid sturgeon to survive, the objective of this study was to quantify survival estimates for hatchery-reared pallid sturgeon stocked into the lower Missouri River. We used stock-recapture data collected from 1994 to 2008 to derive survival estimates based on the Cormack-Jolly-Seber model within program MARK. Since 1994, a total of 78,244 hatchery-reared pallid sturgeon have been released and 1% of these have been recaptured. Recapture numbers by size at stocking were as follows: 48 age 0, 730 age 1, and 38 older than age 1. Stocked age-0 hatchery-reared pallid sturgeon had an estimated apparent survival rate of 0.051 (SE = 0.008), compared with 0.686 (SE=0.117) for age-1 fish and 0.922 (SE=0.015) for fish older than age 1. Our analysis confirms that hatchery-reared pallid sturgeon can survive in the wild and contribute to the overall population of this species. These estimates should provide critical information for decisions regarding stocking strategies within the lower Missouri River and enable biologists to estimate the number of stocked pallid sturgeon that reach sexual maturity. © American Fisheries Society 2010.
Huenemann T.W.,Nebraska Game and Parks Commission |
Dibble E.D.,Fisheries and Aquaculture |
Fleming J.P.,Fisheries and Aquaculture
Transactions of the American Fisheries Society | Year: 2012
Water turbidity has the capacity to influence fish foraging success and behavior. The largemouth bass Micropterus salmoides is a popular sport fish in the southeastern United States that is primarily a visual predator. The high turbidity in many systems can be attributed to sediment loading from agricultural lands, and it can reduce the availability of light in the water column and have direct impacts on largemouth bass foraging success. We investigated the effect of different turbidity levels (0, 10, 25, 50, 100, and 250 nephelometric turbidity units [NTU]) on largemouth bass foraging in aquaria by testing the hypothesis that turbidity has no effect on the time required to locate tethered prey (fatheadminnow Pimephales promelas and golden shiner Notemigonus crysoleucas) or ultimate capture success. The percentages of prey captured that were derived from aggregated data in multiple trials at the different treatment levels differed significantly. One-hundred percent of the largemouth bass in the 0-NTU treatments captured the prey. Conversely, only 15% of the largemouth bass in the 250-NTU treatments captured the prey throughout all trials. The average time taken to capture the prey also was significantly different between treatment combinations, with time to interaction increasing as turbidity increased. The results from this study suggest that greater turbidity levels reduce the ability of largemouth bass to capture prey and increase the time taken to locate and interact with prey. Thus, turbidity may impact individual fitness and management strategies. © American Fisheries Society 2012.
Webb E.B.,Texas Tech University |
Webb E.B.,Arkansas Tech University |
Smith L.M.,Oklahoma State University |
Vrtiska M.P.,Nebraska Game and Parks Commission |
Lagrange T.G.,Nebraska Game and Parks Commission
Journal of Wildlife Management | Year: 2010
Staging areas and migratory stopovers of wetland birds can function as geographic bottlenecks; common dependence among migratory wetland bird species on these sites has major implications for wetland conservation. Although 90 of playa wetlands in the Rainwater Basin (RWB) region of Nebraska, USA, have been destroyed, the area still provides essential stopover habitat for up to 10 million waterfowl each spring. Our objectives were to determine local (within wetland and immediate watershed) and landscape-scale factors influencing wetland bird abundance and species richness during spring migration at RWB playas. We surveyed 3640 playas twice weekly in the RWB and observed approximately 1.6 million individual migratory wetland birds representing 72 species during spring migrations 2002-2004. We tested a priori hypotheses about whether local and landscape variables influenced overall species richness and abundance of geese, dabbling ducks, diving ducks, and shorebirds. Wetland area had a positive influence on goose abundance in all years, whereas percent emergent vegetation and hunting pressure had negative influences. Models predicting dabbling duck abundance differed among years; however, individual wetland area and area of semipermanent wetlands within 10 km of the study wetland consistently had a positive influence on dabbling duck abundance. Percent emergent vegetation also was a positive predictor of dabbling duck abundance in all years, indicating that wetlands with intermediate (50) vegetation coverage have the greatest dabbling duck abundance. Shorebird abundance was positively influenced by wetland area and number of wetlands within 10 km and negatively influenced by water depth. Wetland area, water depth, and area of wetlands within 10 km were all equally important in models predicting overall species richness. Total species richness was positively influenced by wetland area and negatively influenced by water depth and area of semipermanent wetlands within 10 km. Avian species richness also was greatest in wetlands with intermediate vegetation coverage. Restoring playa hydrology should promote intermediate percent cover of emergent vegetation, which will increase use by dabbling ducks and shorebirds, and decrease snow goose (Chen caerulescens) use of these wetlands. We observed a reduction in dabbling duck abundance on wetlands open to spring snow goose hunting and recommend further investigation of the effects of this conservation order on nontarget species. Our results indicate that wildlife managers at migration stopover areas should conserve wetlands in complexes to meet the continuing and future habitat requirements of migratory birds, especially dabbling ducks, during spring migration. © 2010 The Wildlife Society.
Eder B.L.,Nebraska Game and Parks Commission |
Neely B.C.,Parks and Tourism
Fisheries | Year: 2013
Use of geographic information systems (GIS) in fisheries science has increased in prevalence since its introduction in the late 1980s, but use among and within fisheries management agencies has not been quantified. We surveyed 89 administrators of fisheries management agencies in the United States and Canada to determine the current status of GIS in fisheries management and received 54 responses (61% return rate). Survey respondents indicated that GIS was used to help manage fish populations, and 63% of respondents believed that GIS was either "very useful" or "extremely useful" for meeting agency objectives. However, most GIS work conducted by fisheries management agencies was executed by few individuals within the agency or by contracted service. Barriers preventing more widespread use by managers within agencies included lack of knowledge or training and limited time to use GIS in job duties. Our results suggest that GIS is an important tool for fisheries management. Further, GIS use within an agency might be increased by focusing on increased biologist participation in training exercises, integration with existing job duties, and recognizing diversity among GIS software. © 2013 Copyright Taylor and Francis Group, LLC.
Negus L.P.,Oklahoma State University |
Davis C.A.,Oklahoma State University |
Wessel S.E.,Nebraska Game and Parks Commission
American Midland Naturalist | Year: 2010
Throughout the Midwestern U.S., grassland birds have been declining faster than any other group of birds, with the main cause for these declines being the extensive loss of native prairies. During the last 25 y, surrogate grasslands, such as Conservation Reserve Program (CRP) lands, have become increasingly important as an alternative habitat for grassland birds. However, many CRP grasslands that once provided excellent habitat are now dominated by monculture stands of grass, resulting in a less diverse habitat that has reduced wildlife benefits. In summer 2002, the Nebraska Game and Parks Commission and Pheasants Forever partnered with the United States Department of Agriculture's Farm Service Agency and Natural Resource Conservation Service to initiate a program that promotes disking and interseeding legumes as a mid-contract management practice in CRP fields. The objectives of this study were to determine grassland bird abundance and nest-productivity in disked and interseeded CRP fields and evaluate vegetative responses to disking and interseeding. We conducted our study on 16 CRP fields in Stanton County, Nebraska where we used fixed transects to determine avian species richness and abundance and nest-searched twelve 4-ha plots to determine nest productivity in treatment (managed by disking and interseeding) and reference (unmanaged) CRP fields. We also recorded vegetation characteristics along each transect and at each nest. Overall abundance in treatment fields was 4.49 ± 0.25 (se) birds/transect compared to 2.93 ± 0.21 birds/transect in reference fields. Species richness and diversity were also higher in treatment fields. There was no difference in nest density or nest success between treatment and reference fields. Treatment field vegetation had higher percentages of forbs and bare ground than reference sites. Maximum vegetation height and horizontal visual obstruction were also higher in treatment sites. To accommodate the most grassland bird species in CRP fields, management of CRP fields should include establishing an annual rotation of disking/interseeding, while leaving portions of fields in mature grass stands. Future research should focus on methods that will increase the longevity of the vegetation effects of disking/interseeding legumes. © 2010, American Midland Naturalist.
Pasbrig C.A.,University of Nebraska at Kearney |
Koupal K.D.,Nebraska Game and Parks Commission |
Schainost S.,Nebraska Game and Parks Commission |
Wyatt Hoback W.,University of Nebraska at Kearney
Endangered Species Research | Year: 2012
Globally, riverine fishes are affected by degradation of habitat, stream alterations, lost stream connectivity and introduction of non-native species. The plains topminnow Fundulus sciadicus, a small stream-dwelling fish, currently does not have a federal conservation status in the USA; however, anecdotal reports have suggested its decline for the last 20 yr. Our goals were to evaluate the validity of its reported decline and to determine the current range-wide status of this species. We identified 927 historical sites (1889-1999) of occurrence and compiled recent records or re-visited 667 sites (2000-2010). We found plains topminnow at 189 (28.0%) of these sites. Although Nebraska represented the center of distribution and included 66.7% of all historical sites, plains topminnow were only found at 34.4% of historical sites, with the largest declines observed in the Platte and Republican River drainages. Current sampling efforts in Colorado, Missouri, Oklahoma, South Dakota and Wyoming found similar declines. In Iowa and Kansas, plains topminnow was not found, whereas potential increases in distribution were observed in a single drainage in Minnesota and Wyoming. In addition to our sampling efforts, we repeatedly sampled 40 sites within Nebraska to determine detection probability. Detection probabilities for plains topminnow were consistent at 0.76 ± 0.05 (mean ± SE) among sites that were sampled with a single visit. Further research is needed on the species and the potential threats to its occupation of sites, as no singular cause for decline seems plausible. Observed threats include degradation and loss of habitat and shifts in species assemblages towards generalist non-native species. © Inter-Research 2012.
Dinges A.J.,University of Missouri |
Webb E.B.,University of Missouri |
Vrtiska M.P.,Nebraska Game and Parks Commission
Wildlife Biology | Year: 2015
The Light Goose Conservation Order (LGCO) was initiated in 1999 to reduce mid-continent populations of light geese (lesser snow geese Chen caerulescens and Ross's geese C. rossi). However, concern about potential for LGCO activities (i.e. hunting activities) to negatively impact non-target waterfowl species during spring migration in the Rainwater Basin (RWB) of Nebraska prompted agency personnel to limit the number of hunt days each week and close multiple public wetlands to LGCO activities entirely. To evaluate the effects of the LGCO in the RWB, we quantified waterfowl density at wetlands open and closed to LGCO hunting and recorded all hunter encounters during springs 2011 and 2012. We encountered a total of 70 hunting parties on 22 study wetlands, with over 90% of these encounters occurring during early season when the majority of waterfowl used the RWB region. We detected greater overall densities of dabbling ducks Anas spp., as well as for mallards A. platyrhynchos and northern pintails A. acuta on wetlands closed to the LGCO. We detected no effects of hunt day in the analyses of dabbling duck densities. We detected no differences in mean weekly dabbling duck densities among wetlands open to hunting, regardless of weekly or cumulative hunting encounter frequency throughout early season. Additionally, hunting category was not a predictor for the presence of greater white-fronted geese Anser albifrons in a logistic regression model. Given that dabbling duck densities were greater on wetlands closed to hunting, providing wetlands free from hunting disturbance as refugia during the LGCO remains an important management strategy at migration stopover sites. However, given that we did not detect an effect of hunt day or hunting frequency on dabbling duck density, our results suggest increased hunting frequency at sites already open to hunting would likely have minimal impacts on the distribution of non-target waterfowl species using the region for spring staging. © 2015 The Authors.
Steffensen K.D.,Nebraska Game and Parks Commission |
Pegg M.A.,University of Nebraska - Lincoln |
Mestl G.,Nebraska Game and Parks Commission
Journal of Applied Ichthyology | Year: 2013
Summary: Long-term population trends of pallid sturgeon Scaphirhynchus albus in the lower Missouri River were evaluated via a discrete and stochastic age-structure population viability model. The intent of this model was to (i) estimate the local pallid sturgeon population size, (ii) quantify the contribution of hatchery-reared fish to the overall population, (iii) predict the level of natural production needed to create a self-sustaining population, and (iv) determine the parameters that produce the largest model sensitivity. The model estimated that the wild, adult population size was approximately 6000 fish that remained in the lower Missouri River in 2012 compared to approximately 42 000 hatchery-reared pallid sturgeon. Under the assumption of no natural recruitment, the population size will continue to decline at approximately 8% annually, with an annual egg to age-1 survival rate of 0.00011 predicted to maintain a stable population. The model was most sensitive to survival rates of fish ≥ age-1 and less sensitive to age-0 survival rates and fecundity. Decreasing or increasing the female spawning interval by 1 year had minimal effect on the overall population trajectory. Recovery management planning for a species such as pallid sturgeon, which is slow-growing, late-maturing, and has intermittent spawning would require several years to access recovery potential and management decisions. Barring any unforeseen natural catastrophe, the pallid sturgeon population in the lower Missouri River is not in immediate danger of local extirpation; however, the population appears to be far from viable and self-sustaining. © 2013 Blackwell Verlag GmbH.
Steffensen K.D.,Nebraska Game and Parks Commission |
Powell L.A.,University of Nebraska - Lincoln |
Pegg M.A.,University of Nebraska - Lincoln
North American Journal of Fisheries Management | Year: 2012
The population size of pallid sturgeon Scaphirhynchus albus is currently unknown throughout much of the Missouri River. Listed as federally endangered in 1990, the pallid sturgeon remains one of the rarest fishes in the Missouri and Mississippi River basins, and little to no natural recruitment occurs. Artificial population supplementation via a hatchery propagation program was initiated, necessitating the collection of sexually mature pallid sturgeon. Therefore, the Nebraska Game and Parks Commission maintained an intensive broodstock collection and mark– recapture effort from 2008 to 2010 to capture reproductively ready adults for the propagation program. Coordinated crews fished baited trotlines from the confluence of the Platte and Missouri rivers at river kilometer (rkm) 957.6 to a point about 80.5 rkm downstream. A total of 438 pallid sturgeon were captured, which amounts to a 7.8% recapture rate. The objectives of the study were to (1) use these data to estimate the annual population sizes of wild-origin and hatchery-reared pallid sturgeon within the above-mentioned 80.5-rkm reach of the lower Missouri River and (2) compare current population levels with the Pallid Sturgeon Recovery Team’s population objective. We used the mark–recapture data in a robust-design analysis to derive population estimates and annual survival, capture, and temporary emigration rates. The annual population estimate for wild pallid sturgeon varied from 5.4 to 8.9 fish/rkm, whereas the estimate for known hatchery-reared fish varied from 28.6 to 32.3 fish/rkm. The robust-design approach to our analysis resulted in useful estimates of population size and other variables important to quantifying species recovery and management targets; the approach may be suitable for other fisheries management data sets. © American Fisheries Society 2012.
Cariveau A.B.,Rocky Mountain Bird Observatory |
Pavlacky Jr. D.C.,Rocky Mountain Bird Observatory |
Bishop A.A.,U.S. Fish and Wildlife Service |
Lagrange T.G.,Nebraska Game and Parks Commission
Wetlands | Year: 2011
Many isolated wetlands that fill by rainfall, such as playas, have been affected by sedimentation in heavily modified agricultural landscapes. Conservation plantings and buffers reduce sedimentation in wetlands but also may reduce the frequency of inundation. We studied the effects of surrounding landcover on the responses of playas in southwestern Nebraska to heavy rain events using aerial photography, ground surveys, and GIS landscape analyses. Using a generalized linear mixed model, we found that playas in rangeland were more likely to become inundated than playas in cropland, and both were more likely to become inundated than playas in fields enrolled in USDA's Conservation Reserve Program (CRP), typified by tall, dense grasses. Inundation was also positively related to rainfall amount and playa size. Our results highlight the significance of maintaining playas in native prairie and underscore the importance of planting and managing appropriate mixes of native shortgrass and/or mixed-grass prairie species surrounding playas to mimic the vegetative structure of native prairie. In light of historic wetland losses, a reduction in the probability of flooding for individual playas in CRP must be weighed against the protection from sedimentation that buffers afford wetlands in cropland and other beneficial influences of CRP in the landscape. © 2011 Society of Wetland Scientists.