scholarly journals Size structured populations: Dispersion effects due to stochastic variability of the individual growth rate

2000 ◽  
Vol 31 (4-5) ◽  
pp. 27-34 ◽  
Author(s):  
G Buffoni ◽  
A Cappelletti
Keyword(s):  
Growth Rate ◽  
Structured Populations ◽  
Individual Growth ◽  
Dispersion Effects ◽  
Individual Growth Rate ◽  
The Individual

scholarly journals The regulating effect of growth plasticity on the dynamics of structured populations

2021 ◽  
Author(s):  
Jasper Croll ◽  
André M. de Roos
Keyword(s):  
Growth Rate ◽  
Population Cycles ◽  
Population Level ◽  
Structured Populations ◽  
Individual Growth ◽  
Structured Population Model ◽  
Consumer Population ◽  
Individual Growth Rate ◽  
The Individual ◽  
Growth And Reproduction

Abstract Plasticity is the extent to which life history processes such as growth and reproduction depend on the environment. Plasticity in individual growth varies widely between taxa. Nonetheless, little is known about the effect of plasticity in individual growth on the ecological dynamics of populations. In this article we analyse a physiologically structured population model of a consumer population in which the individual growth rate can be varied between entirely plastic to entirely non-plastic. We derive this population level model from a dynamic energy budget model to ensure an accurate energetic coupling between ingestion, somatic maintenance, growth, and reproduction within an individual. We show that the consumer population is either limited by adult fecundity or juvenile survival up to maturation, depending on the level of growth plasticity and the non-plastic individual growth rate. Under these two regimes we also find two different types of population cycles which again arise due to fluctuation in respectively juvenile growth rate or adult fecundity. In the end our model not only provides insight into the effects of growth plasticity on population dynamics, but also provides a link between the dynamics found in age- and size-structured models.

scholarly journals The effect of growth rate on otolith-based discrimination of cod (Gadus morhua) ecotypes

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0247630
Author(s):  
Einar Pétur Jónsson ◽  
Steven E. Campana ◽  
Jón Sólmundsson ◽  
Klara B. Jakobsdóttir ◽  
Hlynur Bárðarson
Keyword(s):  
Growth Rate ◽  
Gadus Morhua ◽  
Sampling Period ◽  
Individual Growth ◽  
Discrete Wavelet ◽  
Shape Variation ◽  
Otolith Shape ◽  
Individual Growth Rate ◽  
The Individual ◽  
The Relationship

Otolith shape has previously been used to identify ecotypes within the Icelandic cod (Gadus morhua) stock, using DST profiles to validate the results. Fish otolith shape variation has repeatedly been found to be largely determined by growth rate. To examine the effect of growth rate on the relationship between otolith shape and cod ecotypes (using the Pan I genotype as a proxy for ecotype), 826 archived sagittal otoliths collected over a 58 year sampling period were retrieved, the individual growth rate calculated, and otolith shape described using both Normalized Elliptic Fourier transform and Discrete Wavelet transform. Discriminant functions of otolith shape successfully classified ecotype, whether using Fourier or Wavelet descriptors, but only when excluding a heterozygous genotype from the analysis. The otolith shape variability of this genotype lowered the classification success, while otolith shape, in turn, was significantly affected by growth rate and cohort. Growth rate differences previously reported for the ecotypes were present, but were less marked than expected and indeed, growth rate variance attributable to ecotype identity was dwarfed by cohort- and location-related variance in growth. Such a strong effect of growth rate suggests that cod ecotype discrimination based on otolith shape is sensitive to both temporal and spatial variations in growth, which can mask the effect of ecotype-related growth rate differences on otolith shape.

scholarly journals Otolith-based discrimination of cod ecotypes and the effect of growth rate

2021 ◽  
Author(s):  
Einar Pétur Jónsson ◽  
Steven E. Campana ◽  
Jón Sólmundsson ◽  
Klara B. Jakobsdóttir ◽  
Hlynur Bárðarson
Keyword(s):  
Growth Rate ◽  
Gadus Morhua ◽  
Sampling Period ◽  
Individual Growth ◽  
Discrete Wavelet ◽  
Shape Variation ◽  
Otolith Shape ◽  
Individual Growth Rate ◽  
The Individual ◽  
The Relationship

AbstractOtolith shape has previously been used to identify ecotypes within the Icelandic cod (Gadus morhua) stock, using DST profiles to validate the results. Fish otolith shape variation has repeatedly been found to be largely determined by growth rate. To examine the effect of growth rate on the relationship between otolith shape and cod ecotypes (using the Pan I genotype as a proxy for ecotype), 826 archived sagittal otoliths collected over a 52 year sampling period were retrieved, the individual growth rate calculated, and otolith shape described using both Normalized Elliptic Fourier transform and Discrete Wavelet transform. Discriminant functions of otolith shape yielded high ecotype classification success, whether using Fourier or Wavelet descriptors, but only when excluding a heterozygous genotype from the analysis. The otolith shape variability of this genotype lowered the classification success, while otolith shape, in turn, was significantly affected by growth rate and cohort. Growth rate differences previously reported for the ecotypes were present, but were less marked than expected and indeed, growth rate variance attributable to ecotype identity was dwarfed by cohort- and location-related variance in growth. Such a strong effect of growth rate suggests that cod ecotype discrimination based on otolith shape is sensitive to both temporal and spatial variations in growth, which can mask the effect of ecotype-related growth rate differences on otolith shape.

Graphical Estimation of Rates of Mortality and Growth

1970 ◽  
Vol 27 (1) ◽  
pp. 204-208 ◽  
Author(s):  
Roger H. Green
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Individual Growth ◽  
Individual Growth Rate ◽  
Population Mortality ◽  
The Individual ◽  
Average Size ◽  
Individual Size

A method is presented by which the individual growth rate and the population mortality rate can be estimated graphically in certain populations, given only knowledge of maximum individual size and of average size at two times of the year. The four graphs that are given may be used in several different ways, depending on the information available.

Demography of an Estuarine Amphipod (Gammarus lawrencianus) Experimentally Selected for High "r": A Model of the Genetic Effects of Environmental Change

1981 ◽  
Vol 38 (9) ◽  
pp. 1120-1127 ◽  
Author(s):  
R. W. Doyle ◽  
W. Hunte
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Life History Strategy ◽  
Intrinsic Rate ◽  
Individual Growth ◽  
Population Growth Rates ◽  
Phenotypic Correlations ◽  
Demographic Traits ◽  
Marine Crustacean ◽  
Individual Growth Rate

The estuarine amphipod Gammarus lawrencianus was subjected to prolonged selection (3 years; 26 generations) for high population growth rates. The demography of the selected population was studied in detail and compared under laboratory conditions with animals derived from a control (wild) population collected in the same area 3 years later. In the lab-adapted population the intrinsic rate of population growth r increased by 72% as the result of changes in age at maturation, survivorship, and fecundity. The variance of these traits decreased and Crow's (1958) index of total selection (variance of fitness/mean fitness squared) is proposed as a quantitative and operational measure of genetic adaptation to a changed environment. Possible limitations on adaptation were investigated by examining the correlations among demographic traits within the lab-adapted population. Some phenotypic correlations were determined directly and others by an indirect technique using information from full siblings. Individual growth rate was negatively correlated both with survival and fecundity. Individual growth rate and age at sexual maturity were also negatively correlated. Negative phenotypic correlations between traits may indicate limitations on long-term adaptation. We conclude that significant evolutionary changes in the demographic traits of this (and presumably other) marine crustacean can occur within a time scale of interest to ecologists and aquaculturalists.Key words: adaptation, amphipod, aquaculture, Crustacea, evolution, Gammarus, genetics, life history, strategy

Is boldness towards predators related to growth rate in naïve captive-reared Arctic char (Salvelinus alpinus)?

2007 ◽  
Vol 64 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Mika VM Laakkonen ◽  
Heikki Hirvonen
Keyword(s):  
Growth Rate ◽  
Captive Breeding ◽  
Salvelinus Alpinus ◽  
Antipredator Behavior ◽  
Underlying Mechanism ◽  
Arctic Char ◽  
Individual Growth ◽  
Detailed Knowledge ◽  
Individual Growth Rate ◽  
Slow Growing

Previous studies have shown that the antipredator responsiveness of fish degenerates through generations in captive breeding. However, detailed knowledge of the underlying mechanism is still largely lacking. We tested the hypothesis that hatchery fish supposedly selected for faster growth in the hatchery environment are bolder towards predators than their slower-growing conspecifics. This was examined by comparing the antipredator behavior of predator- naïve fast- and slow-growing individuals of a captive-bred Arctic char (Salvelinus alpinus) population to chemical cues from natural predators burbot (Lota lota) and pikeperch (Sander lucioperca). As behavioral responses depended on char body size, we compared boldness towards predators of size-matched fast- and slow-growing char. We found no differences in four behavioral antipredator traits between size-matched groups of fast- and slow-growing char. According to these results, boldness to predator cues is not related to individual growth rate in captive-bred Arctic char.

Influence of growth and survival costs of reproduction on Atlantic cod, Gadus morhua, population growth rate

1999 ◽  
Vol 56 (9) ◽  
pp. 1612-1623 ◽  
Author(s):  
Jeffrey A Hutchings
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Environmental Stochasticity ◽  
Individual Growth ◽  
Growth And Survival ◽  
Individual Growth Rate ◽  
Age Structured ◽  
Reproductive Rates

A stochastic, age-structured life history model was used to examine how age at maturity (theta), pre- (Zimm) and postreproductive (Zmat) mortality, and postreproductive growth rate can affect maximum reproductive rates of fish at low population size. Simulations suggest that annual (r) and per-generation (R0) metrics of population growth for Newfoundland's northern Grand Bank Atlantic cod, Gadus morhua, are primarily influenced by changes to mortality prior to and following reproduction. At observed weights at age and Zmat = 0.2, r ranged between 0.135 and 0.164 for cod maturing at between 4 and 7 years. Incremental increases in either Zimm or Zmat of 0.1 were associated with 0.03-0.05 reductions in r. To effect similar reductions, individual growth rate would have to decline by approximately one half. At observed weights at age, increases in Zmat from 0.20 to 0.45 increased the probability of negative per-generation growth from 3 to 26% for cod maturing at 4 years and from 6 to 46% for cod maturing at 7 years. Thus, even in the absence of fishing mortality, little or no population growth by Atlantic cod may not be unexpected in the presence of environmental stochasticity, particularly when accompanied by increases in mortality and declining individual growth.

Sign in / Sign up

Export Citation Format

Share Document