scholarly journals Geomorphology and stream habitat relationships with smallmouth bass (Micropterus dolomieu) abundance at multiple spatial scales in eastern Oklahoma

2007 ◽  
Vol 64 (8) ◽  
pp. 1116-1129 ◽  
Author(s):  
Daniel C Dauwalter ◽  
Dale K Splinter ◽  
William L Fisher ◽  
Richard A Marston
Keyword(s):  
Relative Error ◽  
Spatial Scales ◽  
Regression Tree ◽  
Channel Morphology ◽  
Smallmouth Bass ◽  
Stream Habitat ◽  
Micropterus Dolomieu ◽  
Ouachita Mountains ◽  
Order Of Magnitude ◽  
Stream Size

Fluvial geomorphic processes structure habitats important to stream fishes. We determined relationships between densities of smallmouth bass (Micropterus dolomieu) and ecoregions, watershed and reach morphology, and stream habitat in eastern Oklahoma, USA. Watershed and reach morphology were measured at 128 stream sites, and stream habitat and smallmouth bass abundance were measured in 1800 channel units. Variation in stream size, channel morphology, and substrate size constituted major physical differences among sites. Channel morphology differed among ecoregions in the largest streams. Densities of age-0 and age-1 and older smallmouth bass were approximately an order of magnitude greater in the Boston Mountains and Ozark Highlands streams than in Ouachita Mountains streams. Regression tree analysis explained less variation in age-0 (10-fold cross-validated relative error = 0.843) than in age-1 and older (relative error = 0.650) smallmouth bass densities and showed that stream size and channel-unit size were primary determinants of density. Channel morphology explained variation in densities in deep channel units of large streams, which was somewhat independent of ecoregion.

Spatial and temporal distributions of smallmouth bass (Micropterus dolomieu) nests in Lake Opeongo, Ontario

1997 ◽  
Vol 54 (9) ◽  
pp. 2007-2013 ◽  
Author(s):  
C Rejwan ◽  
B J Shuter ◽  
M S Ridgway ◽  
N C Collins
Keyword(s):  
Reproductive Success ◽  
Littoral Zone ◽  
Nest Site ◽  
Spatial Scales ◽  
Smallmouth Bass ◽  
Competitive Interactions ◽  
Micropterus Dolomieu ◽  
Spatial And Temporal Distributions ◽  
Nest Site Choice ◽  
Habitat Variables

Smallmouth bass (Micropterus dolomieu) nests were patchily distributed within the littoral zone of Lake Opeongo at two spatial scales (1 km and 100 m shoreline segments). Nest locations were recorded by snorkelling along 155 and 6.3 km of littoral zone over 4 and 11 years, respectively. The degree of patchiness was greater and occurred more consistently at the 1-km than at the 100-m spatial scale. However, the degree of patchiness was not significantly affected by 200% differences in spawning population size, implying that competitive interactions did not strongly influence nest locations over the study period. High-density nesting areas remained stationary between years at the 1-km and 100-m scales. This suggests that habitat variables having stationary spatial characteristics, influence nest site choice. Since the locations of nest patches are less stationary and less consistent among 100-m than among 1-km scale sites, influential habitat variables at the 100-m scale are either less important to the locations of nests or less stationary from year-to-year in their effects on nest distributions. If stationary nest patches are typical of spawning smallmouth bass in lakes, permanent protection of known patch locations could enhance their reproductive success.

scholarly journals Species-specific preferences drive the differential effects of lake factors on fish production

2020 ◽  
Vol 77 (10) ◽  
pp. 1625-1637
Author(s):  
Lauren A. Jarvis ◽  
Bailey C. McMeans ◽  
Henrique Corrêa Giacomini ◽  
Cindy Chu
Keyword(s):  
Lake Trout ◽  
Cold Water ◽  
Secchi Depth ◽  
Regression Tree ◽  
Smallmouth Bass ◽  
Environmental Drivers ◽  
Predatory Fish ◽  
Fish Production ◽  
Micropterus Dolomieu ◽  
Boosted Regression Tree

As the global human population grows, it remains a top priority for communities, managers, policymakers, and stakeholders to maintain healthy, sustainable, and productive fisheries under continued global change. Here we used a dataset consisting of fish and lake characteristics for 536 lakes across Ontario, Canada, to test whether multiple climate, human, and biological factors differentially affect fish production (i.e., population biomass per hectare per year). We tested the hypothesis that temperature is the key driver of fisheries production by testing for the effects of multiple factors on the production of three top predatory fish species: cold-water lake trout (Salvelinus namaycush), cool-water walleye (Sander vitreus), and warm-water smallmouth bass (Micropterus dolomieu). Using boosted regression tree analyses, we found that lake trout production was most influenced by the volume of hypolimnetic habitat, walleye production was related to other climatic variables, and smallmouth bass production was most influenced by sampling day of the year followed by Secchi depth. Our results suggest that current fish production models — that only include temperature and body size — may oversimplify important ecological complexities and thus misinform management decisions because species respond differently to environmental drivers.

Impacts of road access on lake trout (Salvelinus namaycush) populations: regional scale effects of overexploitation and the introduction of smallmouth bass (Micropterus dolomieu)

2009 ◽  
Vol 66 (2) ◽  
pp. 212-223 ◽  
Author(s):  
Scott D. Kaufman ◽  
Ed Snucins ◽  
John M. Gunn ◽  
Wayne Selinger
Keyword(s):  
Lake Trout ◽  
Scale Effects ◽  
Regional Scale ◽  
Winter Season ◽  
Salvelinus Namaycush ◽  
Smallmouth Bass ◽  
Micropterus Dolomieu ◽  
Excessive Pressure ◽  
Fishing Activity ◽  
Remote Lakes

In lake trout ( Salvelinus namaycush ) lakes of northeastern Ontario, Canada, aerial surveys of fishing activity on individual lakes (N = 589) and quantitative gillnet surveys (N = 65) were used to assess the effects of road access on angling effort and the presence of introduced smallmouth bass ( Micropterus dolomieu ). Angling effort, particularly during the open-water season, was highest and often exceeded estimated sustainable levels on lakes with good road access. Approximately 25% of the remote lakes also received excessive pressure during the winter season. Angler numerical responses to lake trout abundance were detected in remote lakes, but not in road-accessible lakes. Smallmouth bass were more prevalent in lakes with road access and human settlement (either cottages or lodges), supporting the theory that they were introduced into these lakes. Lake trout populations were depleted throughout much of the study range. Even without road access or smallmouth bass, lake trout abundance was still 47% lower than in unexploited reference lakes. When bass and (or) road access were present, lake trout abundance decreased by 77%. Remote lake trout populations in this area are clearly vulnerable to the negative impacts of improved access, a vector for both overexploitation and species introductions.

scholarly journals River Otter, Lontra canadensis, Food Habits in the Missouri Ozarks

2008 ◽  
Vol 122 (4) ◽  
pp. 303 ◽  
Author(s):  
Nathan M. Roberts ◽  
Charles F. Rabeni ◽  
John S. Stanovick ◽  
David A. Hamilton
Keyword(s):  
Smallmouth Bass ◽  
Lontra Canadensis ◽  
Micropterus Dolomieu ◽  
Widespread Occurrence ◽  
River Otters ◽  
Lepomis Megalotis ◽  
Rock Bass ◽  
Longear Sunfish ◽  
The Mean ◽  
Ambloplites Rupestris

The reintroduction of River Otters (Lontra canadensis) between 1982 and 1992 resulted in widespread occurrence of the species throughout the Missouri Ozarks. This study examined otter diets from the vicinity of two Ozark streams in relation to seasonal and spatial trends. Otter scats (N = 4750) were collected and analyzed from the Osage Fork River and Big Piney River during the summer and winter seasons of 2001 and 2002. During the winter (January-March), fish occurred in 86% of the samples. During the summer (June–August), occurrence of fish dropped to approximately 15% for both rivers. Seven families of fish were identified in the diets, with Centrarchidae being most common regardless of river or season. Within the Centrarchidae, the genus Lepomis (mostly Longear Sunfish, Lepomis megalotis) was most common, with Micropterus (mostly Smallmouth Bass, Micropterus dolomieu) and Rock Bass (Ambloplites rupestris) also well represented. The mean age of Ambloplites consumed (mean = 3.3 years) was consistently older than that of either Micropterus (mean = 2.54 years) or Lepomis (mean = 2.78 years). Crayfish were recovered from a mean of 85.2% of scats in the winter and 99% in the summer. Smaller fish and crayfish were more common from the upper reaches of the streams while larger fish were prevalent in the lower reaches.

scholarly journals Assessment of the Impacts of Image Signal-to-Noise Ratios in Impervious Surface Mapping

2019 ◽  
Vol 11 (22) ◽  
pp. 2603
Author(s):  
George Xian ◽  
Hua Shi ◽  
Cody Anderson ◽  
Zhuoting Wu
Keyword(s):  
Spatial Resolution ◽  
Signal To Noise Ratio ◽  
Spatial Scales ◽  
Regression Tree ◽  
Remote Sensing Data ◽  
Impervious Surface ◽  
Landsat 8 ◽  
Signal To Noise ◽  
Study Results ◽  
The Impact

Medium spatial resolution satellite images are frequently used to characterize thematic land cover and a continuous field at both regional and global scales. However, high spatial resolution remote sensing data can provide details in landscape structures, especially in the urban environment. With upgrades to spatial resolution and spectral coverage for many satellite sensors, the impact of the signal-to-noise ratio (SNR) in characterizing a landscape with highly heterogeneous features at the sub-pixel level is still uncertain. This study used WorldView-3 (WV3) images as a basis to evaluate the impacts of SNR on mapping a fractional developed impervious surface area (ISA). The point spread function (PSF) from the Landsat 8 Operational Land Imager (OLI) was used to resample the WV3 images to three different resolutions: 10 m, 20 m, and 30 m. Noise was then added to the resampled WV3 images to simulate different fractional levels of OLI SNRs. Furthermore, regression tree algorithms were incorporated into these images to estimate the ISA at different spatial scales. The study results showed that the total areal estimate could be improved by about 1% and 0.4% at 10-m spatial resolutions in our two study areas when the SNR changes from half to twice that of the Landsat OLI SNR level. Such improvement is more obvious in the high imperviousness ranges. The root-mean-square-error of ISA estimates using images that have twice and two-thirds the SNRs of OLI varied consistently from high to low when spatial resolutions changed from 10 m to 20 m. The increase of SNR, however, did not improve the overall performance of ISA estimates at 30 m.

scholarly journals Quantifying the Radiative Impact of Clouds on Tropopause Layer Cooling in Tropical Cyclones

2020 ◽  
Vol 33 (15) ◽  
pp. 5527-5542
Author(s):  
Louis Rivoire ◽  
Thomas Birner ◽  
John A. Knaff ◽  
Natalie Tourville
Keyword(s):  
Tropical Cyclones ◽  
Spatial Scales ◽  
Radiative Heating ◽  
Orthogonal Polarization ◽  
Heating Rates ◽  
Tropical Tropopause Layer ◽  
Convective Clouds ◽  
Tropical Tropopause ◽  
Convective Region ◽  
Order Of Magnitude

AbstractA ubiquitous cold signal near the tropopause, here called “tropopause layer cooling” (TLC), has been documented in deep convective regions such as tropical cyclones (TCs). Temperature retrievals from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) reveal cooling of order 0.1–1 K day−1 on spatial scales of order 1000 km above TCs. Data from the Cloud Profiling Radar (onboard CloudSat) and from the Cloud–Aerosol Lidar with Orthogonal Polarization [onboard the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)] are used to analyze cloud distributions associated with TCs. Evidence is found that convective clouds within TCs reach the upper part of the tropical tropopause layer (TTL) more frequently than do convective clouds outside TCs, raising the possibility that convective clouds within TCs and associated cirrus clouds modulate TLC. The contribution of clouds to radiative heating rates is then quantified using the CloudSat and CALIPSO datasets: in the lower TTL (below the tropopause), clouds produce longwave cooling of order 0.1–1 K day−1 inside the TC main convective region, and longwave warming of order 0.01–0.1 K day−1 outside; in the upper TTL (near and above the tropopause), clouds produce longwave cooling of the same order as TLC inside the TC main convective region, and up to one order of magnitude smaller outside. Considering that clouds also produce shortwave warming, it is suggested that cloud radiative effects inside and outside TCs only explain modest amounts of TLC while other processes must provide the remaining cooling.

scholarly journals Central Molecular Zone of the Milky Way: Star Formation in an extreme Environment

2015 ◽  
Vol 11 (S315) ◽  
pp. 163-166
Author(s):  
Jens Kauffmann
Keyword(s):  
Star Formation ◽  
Milky Way ◽  
Spatial Scales ◽  
Extreme Environment ◽  
Average Density ◽  
High Mass ◽  
Density Structure ◽  
Star Formation Activity ◽  
Order Of Magnitude ◽  
Sgr A

AbstractThe Central Molecular Zone (CMZ; inner ~100 pc) hosts some of the most dense and massive molecular clouds of the Milky Way. These clouds might serve as local templates for dense clouds seen in nearby starburst galaxies or in the early universe. The clouds have a striking feature: they form stars at a very slow pace, considering their mass and high average density. Here we use interferometer data from ALMA and the SMA to show that this slow star formation is a consequence of the cloud density structure: CMZ clouds have a very flat density structure. They might, for example, exceed the average density of the Orion A molecular cloud by an order of magnitude on spatial scales ~5 pc, but CMZ “cores” of ~0.1 pc radius have masses and densities lower than what is found in the Orion KL region. This absence of highest–density gas probably explains the suppression of star formation. The clouds are relatively turbulent, and ALMA observations of H2CO and SiO indicate that the turbulence is induced by high–velocity shocks. We speculate that these shocks might prevent the formation of high–mass cores. It has been argued that the state of CMZ clouds depends on their position along the orbit around Sgr A*. Our incomplete data indicate no evolution in the density structure, and only a modest evolution in star formation activity per unit mass.

Heavy metal pollution and macrobenthic assemblages in soft sediments in two Sydney estuaries, Australia

1998 ◽  
Vol 49 (6) ◽  
pp. 533 ◽  
Author(s):  
Jonathan S. Stark
Keyword(s):  
Heavy Metals ◽  
Environmental Variables ◽  
Spatial Scales ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soft Sediments ◽  
Lead And Zinc ◽  
Macrobenthic Assemblages ◽  
Order Of Magnitude ◽  
Copper Lead

The influence of heavy metals (copper, lead and zinc) associated with urban runoff, on assemblages of macrofauna in intertidal soft sediments was studied in two estuaries in the Sydney region. The patterns of distribution and abundance of fauna and assemblages was found to vary significantly at several spatial scales: within bays in an estuary, between bays within an estuary and between bays from different estuaries. Significant differences were found in concentrations of heavy metals in sediments, but there was very little difference among bays in other environmental variables: grain-size characteristics and organic matter content of sediments. Bays polluted by heavy metals had significantly different assemblages to unpolluted bays, were generally less diverse and were characterized by an order-of-magnitude greater abundance of capitellids, spionids, nereids and bivalves. Unpolluted bays had greater abundance of crustaceans and several polychaete families, including paraonids and nephtyids and were generally more diverse. There was a significant correlation between patterns of assemblages and concentrations of heavy metals, but not with other environmental variables.

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