Bioenergetic trajectories underlying partial migration in Patuxent River (Chesapeake Bay) white perch (Morone americana)

2009 ◽  
Vol 66 (4) ◽  
pp. 602-612 ◽  
Author(s):  
Lisa A. Kerr ◽  
David H. Secor
Keyword(s):  
Growth Rates ◽  
White Perch ◽  
Growth Conditions ◽  
Partial Migration ◽  
Related Phenomenon ◽  
Morone Americana ◽  
Scope For Growth ◽  
Patuxent River ◽  
Consumption Rates ◽  
First Year Of Life

Partial migration, the coexistence of resident and migratory individuals within the same population, may be common in fish populations. A proposed mechanism underlying partial migration is differing dispersive responses to early growth conditions, but few studies have explicitly tested this. During their first year of life, white perch ( Morone americana ) in the Patuxent River (Maryland, USA) exhibit either residency in freshwater natal habitats (resident contingent) or disperse down-estuary into brackish habitats (dispersive contingent). We tested whether white perch juveniles exhibited differing growth and metabolic trajectories based on contingent membership or in response to salinity. A randomized factorial experiment with two contingent types and two salinity treatments (1 and 8) was conducted over a 30-day period. The experiments supported a contingent effect, with the dispersive contingent exhibiting higher consumption rates and a higher scope for growth. In addition, we identified a weak salinity effect with evidence of increased consumption and routine metabolism in mesohaline conditions. Juvenile growth rates calculated from individuals in the field supported laboratory results, with dispersive contingent members exhibiting higher growth rates. We conclude that contingent membership and the related phenomenon of partial migration in this population is associated with varying energetic tactics that significantly influence the scope for growth.

Interactions between White Perch (Morone amerićana) and Yellow Perch (Perca flavescens) in Lake Erie as Determined from Feeding and Growth

1990 ◽  
Vol 47 (9) ◽  
pp. 1779-1787 ◽  
Author(s):  
Donna L. Parrish ◽  
F. Joseph Margraf
Keyword(s):  
Food Consumption ◽  
Yellow Perch ◽  
White Perch ◽  
Perca Flavescens ◽  
Diet Overlap ◽  
Central Basin ◽  
Morone Americana ◽  
Western Basin ◽  
Consumption Rates ◽  
Growth Differences

Since the mid-1970's, white perch Morone americana have expanded rapidly, resulting in possible major interactions with the native yellow perch Perca flavescens. We compared the food consumption rates, diet overlap, and growth of white perch and yellow perch from field data collected during 1983–85 and 1987. Food consumption rates were as much as 27% greater in white perch than in yellow perch, and were higher for both species in the central basin than in the western basin. Seasonal diet composition was most alike in summer and less so in spring and fall, when yellow perch ate more benthos or fish than did white perch. Of 48 Schoener index comparisons of diet overlap during a 3-yr period, 52% were significant (> 0.6). Although yellow perch grew faster in the central basin, reflecting the greater consumption rates, white perch did not show the similar large interbasin growth differences.

Effects of turbidity on prey consumption and growth in brook trout and implications for bioenergetics modeling

2001 ◽  
Vol 58 (2) ◽  
pp. 386-393 ◽  
Author(s):  
John A Sweka ◽  
Kyle J Hartman
Keyword(s):  
Growth Rates ◽  
Brook Trout ◽  
Specific Growth ◽  
Abiotic Factors ◽  
Foraging Strategies ◽  
Turbid Water ◽  
Daily Consumption ◽  
Consumption Rates ◽  
The Difference ◽  
Specific Growth Rates

Brook trout (Salvelinus fontinalis) were held in an artificial stream to observe the influence of turbidity on mean daily consumption and specific growth rates. Treatment turbidity levels ranged from clear (<3.0 nephelometric turbidity units (NTU)) to very turbid water (> 40 NTU). Observed mean daily specific consumption rates were standardized to the mean weight of all brook trout tested. Turbidity had no significant effect on mean daily consumption, but specific growth rates decreased significantly as turbidity increased. Brook trout in turbid water became more active and switched foraging strategies from drift feeding to active searching. This switch was energetically costly and resulted in lower specific growth rates in turbid water as compared with clear water. Bioenergetics simulations were run to compare observed growth with that predicted by the model. Observed growth values fell below those predicted by the model and the difference increased as turbidity increased. Abiotic factors, such as turbidity, which bring about changes in the activity rates of fish, can have implications for the accuracy of predicted growth by bioenergetics models.

Age, stucture, growth rates and movements of sea mullet, Mugil cephalus L., and Yellow-eye Mullet, Aldrichetta forsteri (Valenciennes), in the Swan-Avon river system, Western Australia

1981 ◽  
Vol 32 (4) ◽  
pp. 605 ◽  
Author(s):  
CF Chubb ◽  
IC Potter ◽  
CJ Grant ◽  
RCJ Lenanton ◽  
J Wallace
Keyword(s):  
Growth Rates ◽  
River System ◽  
First Year ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Using Data ◽  
The Times ◽  
First Year Of Life ◽  
Breeding Seasons ◽  
System 1

The age structure, growth rates and movements of M. cephalus and A forsteri in the Swan-Avon river system have been investigated using data obtained from beach seining and gill netting carried out between February 1977 and June 1980. Length-frequency data and scale readings show that the populations of both species consist predominantly of 0+ and 1 + fish. From the times when the smallest fry (20-30 mm) were present in the lower part of the river system, and from the condition of the gonads of older fish, the breeding seasons of the sea and yellow-eye mullets have been estimated as extending from March to September and from March to August respectively. The bimodality or polymodality exhibited by the length-frequency distributions for the 0 + year classes suggest that in both species groups of individuals spawn at slightly different times. The range of mean total lengths and weights of animals caught in May near the end of the first year of life was 178-222 mm and 64-119 gin M. cephalus and 136-154 mm and 19-30 g in A. forsteri, which shows that the growth of each of these two species of mullet is relatively very rapid in the Swan-Avon river system. 1 + and 2 + fish tend to leave the estuary for varying periods. Although 0+ fish of both species utilized the shallow banks of the estuary throughout the year. the sea mullet moved further upstream and were not as consistently abundant in the lower estuary. Since 0+ yellow-eye mullet 40-100 mm long were also abundant in marine coastal waters between January and May. and sea mullet of comparable age were rarely observed in these regions, it would appear that M. cephalus is the more estuarine-dependent of the two species. Commercial catches of M. cephalus were greater than those of A. forsteri. This feature can be related in part to the much faster growth rate of M. cephalus, which results in a larger proportion of its youngest year classes reaching the minimum legal size for capture prior to the time when they leave the estuary in large numbers.

scholarly journals Chromosome segregation in B. subtilis is highly heterogeneous

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Nina El Najjar ◽  
Peter L. Graumann
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Chromosome Segregation ◽  
Growth Rates ◽  
Slow Growth ◽  
Growth Conditions ◽  
Single Chromosome ◽  
Copy Numbers ◽  
Initiation Of Replication ◽  
Bacterial Cell Cycle

Abstract Objective The bacterial cell cycle comprises initiation of replication and ensuing elongation, concomitant chromosome segregation (in some organisms with a delay termed cohesion), and finally cell division. By quantifying the number of origin and terminus regions in exponentially growing Bacillus subtilis cells, and after induction of DNA damage, we aimed at determining cell cycle parameters at different growth rates at a single cell level. Results B. subtilis cells are mostly mero-oligoploid during fast growth and diploid during slow growth. However, we found that the number of replication origins and of termini is highly heterogeneous within the cell population at two different growth rates, and that even at slow growth, a majority of cells attempts to maintain more than a single chromosome at all times of the cell cycle. Heterogeneity of chromosome copy numbers may reflect different subpopulations having diverging growth rates even during exponential growth conditions. Cells continued to initiate replication and segregate chromosomes after induction of DNA damage, as judged by an increase in origin numbers per cell, showing that replication and segregation are relatively robust against cell cycle perturbation.

scholarly journals Affordable Phenotyping of Winter Wheat under Field and Controlled Conditions for Drought Tolerance

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 882
Author(s):  
Dhananjay Kumar ◽  
Sandeep Kushwaha ◽  
Chiara Delvento ◽  
Žilvinas Liatukas ◽  
Vivekanand Vivekanand ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Winter Wheat ◽  
Growth Rates ◽  
Plant Biomass ◽  
Growth Conditions ◽  
Seedling Stage ◽  
Growth Stages ◽  
Digital Cameras ◽  
Relative Growth ◽  
Relative Growth Rates

Drought stress is one of the key plant stresses reducing grain yield in cereal crops worldwide. Although it is not a breeding target in Northern Europe, the changing climate and the drought of 2018 have increased its significance in the region. A key challenge, therefore, is to identify novel germplasm with higher drought tolerance, a task that will require continuous characterization of a large number of genotypes. The aim of this work was to assess if phenotyping systems with low-cost consumer-grade digital cameras can be used to characterize germplasm for drought tolerance. To achieve this goal, we built a proximal phenotyping cart mounted with digital cameras and evaluated it by characterizing 142 winter wheat genotypes for drought tolerance under field conditions. The same genotypes were additionally characterized for seedling stage traits by imaging under controlled growth conditions. The analysis revealed that under field conditions, plant biomass, relative growth rates, and Normalized Difference Vegetation Index (NDVI) from different growth stages estimated by imaging were significantly correlated to drought tolerance. Under controlled growth conditions, root count at the seedling stage evaluated by imaging was significantly correlated to adult plant drought tolerance observed in the field. Random forest models were trained by integrating measurements from field and controlled conditions and revealed that plant biomass and relative growth rates at key plant growth stages are important predictors of drought tolerance. Thus, based on the results, it can be concluded that the consumer-grade cameras can be key components of affordable automated phenotyping systems to accelerate pre-breeding for drought tolerance.

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