scholarly journals Growth rate fitting using the von Bertalanffy model: analysis of natural populations of Drepanotrema spp. snails (Gastropoda: Planorbidae)

2007 ◽  
Vol 55 (2) ◽  
Author(s):  
Alejandra Rumi ◽  
Diego E. Gutiérrez Gregoric ◽  
M. Andrea Roche
Keyword(s):  
Growth Rate ◽  
Natural Populations ◽  
Model Analysis ◽  
Von Bertalanffy ◽  
Von Bertalanffy Model

A von Bertalanffy Growth Model with a Seasonally Varying Coefficient

1978 ◽  
Vol 35 (11) ◽  
pp. 1479-1482 ◽  
Author(s):  
James E. Cloern ◽  
Frederic H. Nichols
Keyword(s):  
Growth Rate ◽  
San Francisco ◽  
Growth Model ◽  
Macoma Balthica ◽  
Body Growth ◽  
Von Bertalanffy ◽  
Simple Modification ◽  
Varying Coefficient ◽  
Von Bertalanffy Model ◽  
Hippoglossoides Elassodon

The von Bertalanffy model of body growth is inappropriate for organisms whose growth is restricted to a seasonal period because it assumes that growth rate is invariant with time. Incorporation of a time-varying coefficient significantly improves the capability of the von Bertalanffy equation to describe changing body size of both the bivalve mollusc Macoma balthica in San Francisco Bay and the flathead sole, Hippoglossoides elassodon, in Washington state. This simple modification of the von Bertalanffy model should offer improved predictions of body growth for a variety of other aquatic animals. Key words: Bertalanffy, growth model, growth rate, Macoma balthica

scholarly journals Growth rates in two natural populations of Gasterosteus aculeatus in northwestern Spain: relationships with other life history parameters

2020 ◽  
pp. 233-242
Author(s):  
E. San Miguel ◽  
R. Amaro ◽  
J. Castro ◽  
M. Hermida ◽  
C. Fernández
Keyword(s):  
Life History ◽  
Growth Rates ◽  
Gasterosteus Aculeatus ◽  
Natural Populations ◽  
Nonlinear Function ◽  
Mortality Rates ◽  
Model Parameters ◽  
Peripheral Populations ◽  
Von Bertalanffy ◽  
Von Bertalanffy Model

We analysed growth rates of two natural populations of the three–spined stickleback fish, Gasterosteus aculeatus, in Galicia (north–west of Spain) where it has a strictly annual life cycle. We used the von Bertalanffy growth model to estimate nonlinear function for length–at–age data sets. These European peripheral populations reach the highest growth rates (k of the von Bertalanffy model > 0.4 month–1) known for this species. Instantaneous mortality rates and fecundity were computed using von Bertalanffy model parameters for each population. Mortality rates found in Galician populations were 2.0–2.3 higher times than those observed in general for Gasterosteidae. Combining both mortality and fertility, different intermediate fitness optima in each population were obtained for mature females. Overall, these differences in life history compared to other studied populations of sticklebacks can be interpreted as local adaptations to a Mediterranean climate type with high degree–days. Consequently, these populations at the edges of the species’ range may have adapted to the unique environmental conditions and may be of interest in ecology and conservation.

scholarly journals Growth of the tambaqui Colossoma macropomum (Cuvier) (Characiformes: Characidae): which is the best model?

2005 ◽  
Vol 65 (1) ◽  
pp. 129-139 ◽  
Author(s):  
M. A. H Penna ◽  
M. A Villacorta-Corrêa ◽  
T. Walter ◽  
M. Petrere-JR
Keyword(s):  
Growth Model ◽  
Negative Correlation ◽  
The Other ◽  
Data Sources ◽  
Von Bertalanffy ◽  
Data Set ◽  
Colossoma Macropomum ◽  
Von Bertalanffy Model ◽  
Estimated Parameters ◽  
Schnute Model

In order to decide which is the best growth model for the tambaqui Colossoma macropomum Cuvier, 1818, we utilized 249 and 256 length-at-age ring readings in otholiths and scales respectively, for the same sample of individuals. The Schnute model was utilized and it is concluded that the Von Bertalanffy model is the most adequate for these data, because it proved highly stable for the data set, and only slightly sensitive to the initial values of the estimated parameters. The phi' values estimated from five different data sources presented a CV = 4.78%. The numerical discrepancies between these values are of not much concern due to the high negative correlation between k and L<FONT FACE=Symbol>¥</FONT> viz, so that when one of them increases, the other decreases and the final result in phi' remains nearly unchanged.

A Formulation of the von Bertalanffy Growth Curve when the Growth Rate is Roughly Constant

1969 ◽  
Vol 26 (11) ◽  
pp. 3069-3072 ◽  
Author(s):  
William Knight
Keyword(s):  
Growth Rate ◽  
Growth Curve ◽  
Von Bertalanffy ◽  
Alternate Form ◽  
Usual Form

The author contends that the parameters of any growth curve should be a direct description of the graphical appearance of the data. For growth that is even approximately linear this is not true of the von Bertalanffy curve in its usual form (von Bertalanffy, Human Biol. 10: 181–213, 1938). On the above grounds, an alternate form of the von Bertalanffy curve for use in such instances is proposed.

scholarly journals Beyond demographic buffering: Context dependence in demographic strategies across animals

2021 ◽  
Author(s):  
Omar Lenzi ◽  
Arpat Ozgul ◽  
Roberto Salguero-Gomez ◽  
Maria Paniw
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Temporal Variation ◽  
Population Growth Rate ◽  
Natural Populations ◽  
Environmental Context ◽  
Context Dependence ◽  
Vital Rate ◽  
Rate Variation ◽  
Vital Rates

Temporal variation in vital rates (e.g., survival, reproduction) can decrease the long-term mean performance of a population. Species are therefore expected to evolve demographic strategies that counteract the negative effects of vital rate variation on the population growth rate. One key strategy, demographic buffering, is reflected in a low temporal variation in vital rates critical to population dynamics. However, comparative studies in plants have found little evidence for demographic buffering, and little is known about the prevalence of buffering in animal populations. Here, we used vital rate estimates from 31 natural populations of 29 animal species to assess the prevalence of demographic buffering. We modeled the degree of demographic buffering using a standard measure of correlation between the standard deviation of vital rates and the sensitivity of the population growth rate to changes in such vital rates across populations. We also accounted for the effects of life-history traits, i.e., age at first reproduction and spread of reproduction across the life cycle, on these correlation measures. We found no strong or consistent evidence of demographic buffering across the study populations. Instead, key vital rates could vary substantially depending on the specific environmental context populations experience. We suggest that it is time to look beyond concepts of demographic buffering when studying natural populations towards a stronger focus on the environmental context-dependence of vital-rate variation.

scholarly journals Estimating abundance of the Endangered onager Equus hemionus onager in Qatruiyeh National Park, Iran

Oryx ◽  
2013 ◽  
Vol 47 (2) ◽  
pp. 266-272 ◽  
Author(s):  
Mahmoud-Reza Hemami ◽  
Moslem Momeni
Keyword(s):  
Growth Rate ◽  
Protected Area ◽  
National Park ◽  
Natural Populations ◽  
Distance Sampling ◽  
Line Transect ◽  
Management Interventions ◽  
Equus Hemionus ◽  
Wild Ass ◽  
Semi Arid

AbstractHistorically, the onager or Persian wild ass Equus hemionus onager, endemic to Iran, was widespread on the arid and semi-arid central steppes but only two natural populations remain. We estimated the population density of the onager in Qatruiyeh National Park using line transect distance sampling. Transects were surveyed on three plains in the Park and the results compared with total counts conducted by the Department of Environment. Our estimate (109 onagers per 100 km2; 95% confidence interval 67–179) is similar to that obtained by the total counts (137 onagers per 100 km2). Distance sampling is therefore a promising method for estimating the abundance of the onager. Using the annual censuses performed by the Department of Environment over the last 13 years we estimated that the population has a growth rate of 0.09. During the same period the onager population in the Touran Protected Complex has experienced a severe decline. The high density of onagers within the National Park indicates the unsuitability of adjacent habitats, including Bahram-e-Goor Protected Area, for this species. Lack of sufficient security and poorly distributed water sources appear to be the main reasons discouraging onagers from entering the Bahram-e-Goor Protected Area. We recommend and describe management interventions that could potentially assist in maintaining the last surviving onager populations in Iran.

Growth modelling in accordance with daily water temperature in European grayling (Thymallus thymallusL.)

1999 ◽  
Vol 56 (6) ◽  
pp. 994-1000 ◽  
Author(s):  
J P Mallet ◽  
S Charles ◽  
H Persat ◽  
P Auger
Keyword(s):  
Growth Rate ◽  
Water Temperature ◽  
Good Description ◽  
Biological Significance ◽  
Temperature Fluctuations ◽  
Fish Growth ◽  
Von Bertalanffy ◽  
European Grayling ◽  
Daily Water Temperature ◽  
Daily Water

The model of von Bertalanffy has been and is still widely used to model fish growth, mainly because of its good description of annual growth over the whole life span. However, it does not take into account a seasonal variability in growth rate, an important phenomenon that appears quite well correlated with water temperature fluctuations in temperate climates. In the present study, we demonstrated that it was possible to model such variations by including daily water temperature in the von Bertalanffy growth formula owing to the correlation between the growth coefficient k and water temperature. The model we chose to describe such a correlation includes parameters with obvious biological significance and is mathematically well structured, which allowed an extensive use of our growth model. Hence, we use our new model to describe annual variability in the growth of European grayling (Thymallus thymallus L.) in a river section where water temperature could rise up to the thermal tolerance limit for this species, inducing reduced growth rates and severe mortality events. Finally, we were able to explain the growth rate variability from one year to the next by interannual water temperature fluctuations.

Age, growth and mortality of the garfish, Belone belone (L. 1761) in the Adriatic Sea

2012 ◽  
Vol 93 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Barbara Zorica ◽  
Vanja Čikeš Keč
Keyword(s):  
Adriatic Sea ◽  
Growth Parameters ◽  
Fork Length ◽  
Mortality Rates ◽  
Von Bertalanffy ◽  
Positive Allometry ◽  
Von Bertalanffy Model ◽  
Total Length ◽  
Belone Belone ◽  
Conservation And Management

A sample of 3393 garfish, Belone belone (Linnaeus, 1761) was captured using a seine net between January 2003 and December 2008, along the eastern Adriatic Sea. The range in total length was 20.8–75.4 cm and in weight was 12.21–639.25 g. Length–length equations for converting size measurements (standard length and fork length to total length (TL)) were linear. In the length–weight relationship, positive allometry was established (b = 3.4818). Age, determined from sagittal otoliths, ranged from 1+ to 8+ years. The estimated von Bertalanffy model growth parameters for garfish were L∞ = 90.3 cm, K = 0.158 year−1, t0 = −0.109. Otolith weight was endorsed as a possible age predictor, as it showed highly exponential correlation with total garfish length and age (Wo = 0.0012 TL2.189; Wo = 0.568t1.486). These findings were used to examine mortality rates and exploitation in order to improve conservation and management of this pelagic species.

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