Reproduction, growth and maturity in the black flying-fox, Pteropus alecto (Megachiroptera : Pteropodidae)

1998 ◽  
Vol 46 (4) ◽  
pp. 329 ◽  
Author(s):  
M. J. Vardon ◽  
C. R. Tidemann
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Curves ◽  
Day Length ◽  
Individual Growth ◽  
Young Males ◽  
Weight Growth ◽  
Eastern Australia ◽  
Juvenile Males ◽  
Flying Fox

This paper reviews the timing of reproduction, growth rates and age at maturity of the black flying-fox, Pteropus alecto. This species is found from Sulawesi, Indonesia, south to the central east coast of Australia. In northern Australia at 12ºS most young are born in January–March, in contrast to October–November at 27ºS in eastern Australia, but a small percentage of young are born outside the major birth peaks in both areas. The birth peaks of P. alecto appear to be aligned with periods of maximum plant productivity, rather than day length. The plasticity of breeding season is likely to be an important factor enabling P. alecto to colonise areas from near the equator to 29ºS. Individual growth rates were calculated for 27 P. alecto. The weight growth rate of these animals was 2.40 3.14 g day-1 (mean s.d.), while growth rate of the forearm was 0.19 0.18 mm day-1 (mean s.d.). The growth rate of the forearm of females was significantly greater than for males (P = 0.08). From the mean forearm lengths of animals trapped, separate growth curves were developed for juvenile males (n = 566) and females (n = 610); these indicate that growth rate of females is about 8% higher than that of males. Primiparous females had a forearm length of 171.1 3.4 mm (mean s.d.) (n = 5), which is achieved 15–17 months after birth, but about a third of females with forearm lengths of 160–170 mm have suckled young. Males mature at an age greater than females due to their slower growth rate, a phenomenon known from other megachiropteran species.

A note on growth curves of rabbit lines selected on growth rate or litter size

1993 ◽  
Vol 57 (2) ◽  
pp. 332-334 ◽  
Author(s):  
A. Blasco ◽  
E. Gómez
Keyword(s):  
Growth Rate ◽  
Litter Size ◽  
Growth Curves ◽  
Live Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Standard Errors ◽  
Adult Weight ◽  
Weight Growth ◽  
Using Data

Two synthetic lines of rabbits were used in the experiment. Line V, selected on litter size, and line R, selected on growth rate. Ninety-six animals were randomly collected from 48 litters, taking a male and a female each time. Richards and Gompertz growth curves were fitted. Sexual dimorphism appeared in the line V but not in the R. Values for b and k were similar in all curves. Maximum growth rate took place in weeks 7 to 8. A break due to weaning could be observed in weeks 4 to 5. Although there is a remarkable similarity of the values of all the parameters using data from the first 20 weeks only, the higher standard errors on adult weight would make 30 weeks the preferable time to take data for live-weight growth curves.

scholarly journals Growth Rate Variation and Larval Survival: Inferences from an Individual-Based Size-Dependent Predation Model

1993 ◽  
Vol 50 (1) ◽  
pp. 133-142 ◽  
Author(s):  
James A. Rice ◽  
Thomas J. Miller ◽  
Kenneth A. Rose ◽  
Larry B. Crowder ◽  
Elizabeth A. Marschall ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Individual Variability ◽  
Individual Growth ◽  
Rate Variation ◽  
High Survival ◽  
Initial Growth ◽  
Size Dependent ◽  
The Mean ◽  
Selection For

We used an individual-based Monte Carlo simulation model to explore how changes in the mean and variance of growth rates of individuals in a larval fish cohort interact with size-dependent predation to affect the number and characteristics of individual survivors. Small changes in initial cohort mean growth rate can change survival over the first 60 d of life 10-to 30-fold. But when variance in growth rate among individuals is high, survival can be substantially higher than expected from the initial mean cohort growth rate. Selection for faster-growing individuals becomes stronger with increasing variance and increasing predation rate. In some cases, > 80% of the survivors may come from the upper 25% of the initial growth rate distribution, and the mean growth rate of the survivors may exceed twice the initial mean growth rate. When individual growth rates change from day to day rather than remaining constant, the contribution of atypical individuals is accentuated even further. Counterintuitively, most of the selection for faster-growing individuals happens only after the majority of mortality has already taken place. These results suggest that interactions between individual variability and selective mortality may have important cohort-level implications for survival in fishes.

scholarly journals Individual growth pattern and variability in Serranus scriba: a Bayesian analysis

2009 ◽  
Vol 67 (3) ◽  
pp. 502-512 ◽  
Author(s):  
Josep Alós ◽  
Miquel Palmer ◽  
Salvador Balle ◽  
Antoni Maria Grau ◽  
Beatriz Morales-Nin
Keyword(s):  
Growth Rate ◽  
Bayesian Analysis ◽  
Growth Pattern ◽  
Growth Curves ◽  
Individual Variability ◽  
Growth Patterns ◽  
Individual Growth ◽  
Individual Level ◽  
Population Dynamics Models ◽  
Dynamics Models

Abstract Alós, J., Palmer, M., Balle, S., Grau, A. M., and Morales-Nin, B. 2010. Individual growth pattern and variability in Serranus scriba: a Bayesian analysis. – ICES Journal of Marine Science, 67: 502–512. Variability in growth patterns at an individual level in Serranus scriba is described using a Bayesian approach for a generalized von Bertalanffy growth model that accommodates one change in growth rate at a specific point during the lifespan. The approach enables individual growth curves to be inferred, even in a species with a relatively short lifespan and no commercial value, i.e. limited sample sizes available, but potentially endangered by recreational fishing. The change in growth rate may be the result of differing allocation of energy between reproductive and somatic activities at different ages. Overall, the approach presented provides adequate input for future implementation of population dynamics models that take into account individual variability, e.g. individual-based models, even for species for which limited data are available.

Temperature and day length response of some cocksfoot populations

1967 ◽  
Vol 18 (1) ◽  
pp. 1 ◽  
Author(s):  
P BrouT ◽  
CN Williams ◽  
CA Neal-Smith ◽  
L Albrecht
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Growth Rates ◽  
Leaf Size ◽  
Day Length ◽  
Relative Growth ◽  
Dactylis Glomerata L ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
Short Days

Seedling plants of seven cocksfoot (Dactylis glomerata L.) populations were exposed to day/night temperatures of 20/15, 15/10, 12/7, and 9/4°C at day lengths of either 8 or 16 hr. Leaf size, rate of leaf appearance, and relative growth rate decreased as temperature decreased. At higher temperatures, relative growth rate was greater in long than in short days, but at 9/4° it was greater in short days. Long days increased leaf size but slightly reduced the rate of leaf appearance at higher temperatures; the increased leaf size, however, more than compensated for the slightly lower rate of leaf appearance, so that relative growth rate was greater in long than in short days. At 9/4°, however, greater leaf size did not compensate for the much slower rate of leaf appearance in long days. Growth rates were consequently lower in long than in short days at 9/4°. The populations showed a general similarity in response, although significant differences between populations were recorded for particular treatments. There was no apparent relationship between seedling growth rates at low temperatures in this experiment and winter growth of these populations under field conditions.

Slow and unsteady: growth of the Australian eastern long-necked turtle near the southern end of its natural range

2018 ◽  
Vol 66 (1) ◽  
pp. 77 ◽  
Author(s):  
Bruce C. Chessman
Keyword(s):  
Growth Rates ◽  
Growth Models ◽  
Logistic Models ◽  
Individual Growth ◽  
Freshwater Turtles ◽  
Turtle Species ◽  
Adult Growth ◽  
Eastern Australia ◽  
Natural Range ◽  
Chelodina Longicollis

Knowledge of growth rates and maturation times of freshwater turtles is important in assessing population viability. I analysed growth of Australian eastern long-necked turtles (Chelodina longicollis) from individual capture–recapture records spanning periods of up to 17 years for a population in Gippsland, Victoria, close to the high-latitude end of the species’ natural range. Juvenile growth was rapid and similar among individuals but adult growth was usually slow, highly variable among individuals and erratic within individuals over time. In addition, asymptotic body lengths were disparate among individuals for both males and females. Von Bertalanffy growth models fitted separately to males plus unsexed juveniles and females plus unsexed juveniles performed better than logistic models but tended to underestimate growth rates for very small and very large turtles and overestimate growth for medium-sized individuals. Sexual maturity was estimated to be achieved at 10 years in males and 16 years in females, which is late compared with most estimates for other populations of C. longicollis and for other turtle species in south-eastern Australia. The high variability of individual growth in this population makes age estimation from body size unreliable beyond the first few years of life.

Growth rate estimates for New Zealand Rig (Mustelus lenticulatus)

1992 ◽  
Vol 43 (5) ◽  
pp. 1157 ◽  
Author(s):  
MP Francis ◽  
RICC Francis
Keyword(s):  
Growth Rate ◽  
New Zealand ◽  
Frequency Analysis ◽  
Growth Rates ◽  
Growth Curves ◽  
Combined Effects ◽  
Length Frequency ◽  
Total Length ◽  
Males And Females ◽  
Length Frequency Analysis

Growth rate estimates were obtained for New Zealand rig (Mustelus lenticulatus) by analysing length frequency and tag-recapture data. Rig (0+) sampled by set-net in Porirua and Pauatahanui Inlets grew from about 25-30 cm total length at birth to 46-49 cm at age of about 6 months. Samples of juvenile and adult rig trawled in Pegasus Bay and Hauraki Gulf suffered from under-representation of large adults, probably because of escapement. Growth curves derived from length-frequency analysis indicated that Pegasus Bay males matured at 5.0 years and had a minimum longevity of 12 years. Hauraki Gulf males and females matured at 3.7 and 4.7 years, respectively. Growth rates and ages at maturity fell within the ranges reported for other Mustelus species. Tagging data for South Island rig suggested that females grew faster than males. However, growth rate estimates from length-frequency analysis were 2.7-3.3 times greater than estimates from tagging data, probably because the latter were biased by the combined effects of tagging on growth and set-net mesh selectivity.

scholarly journals Historical analysis of somatic growth of Chilean hake (Merluccius gayi gayi) off central coast of Chile

2017 ◽  
Vol 41 (3) ◽  
pp. 558-569
Author(s):  
Francisco Cerna ◽  
Luis A. Cubillos ◽  
Guido Plaza
Keyword(s):  
Growth Rate ◽  
Growth Parameters ◽  
Historical Analysis ◽  
Somatic Growth ◽  
Growth Curves ◽  
Individual Growth ◽  
Linear Mixed Effect Model ◽  
Central Coast ◽  
Mixed Effect ◽  
Average Growth

Somatic growth was studied in the Chilean hake stock off central coast of Chile, through the application of Von Bertalanffy equation (vB) as a non-linear mixed effect model (NLME) on length-at-agedata derived from otolith readings made at Instituto de Fomento Pesquero since 1972. Average growth rates for each year from 1972 to 2009 were estimated. Growth parameters of vB curves were analyzed for three major periods regarding changes in stock biomass (1972-1990, 1991-2003 and 2004-2009). Results indicated that the average growth rate showed inter-annual variations that did not exceed ±15 cm of total length around the historical average of males and females, showing no persistent tendency towards sustained increase or decrease in somatic growth rate. Growth curves obtained with the vB parameters, estimated for the three periods, showed a similar trajectories until age 7 and 8 years, in both male and females. Changes after this age may be a result of a decrease of larger fish removed by the selective effect of fishing, which triggered variations in the fitted curves, but not necessarily changes in somatic growth of these ages in the population. The results demonstrated that the individual growth of hake has not changed significantly since 1972, without observing a density-dependent effect with decreasing abundance.

Modelling Maximum Stem Basal Area Growth Rates of Individual Trees of Eucalyptus pilularis Smith

2021 ◽  
Author(s):  
P W West
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Basal Area ◽  
Maximum Growth ◽  
Tree Size ◽  
Stem Diameter ◽  
Tree Age ◽  
Productive Capacity ◽  
Eastern Australia ◽  
Eucalyptus Pilularis

Abstract The growth rate of a tree at any time relates to its size and the level of competition exerted by its neighbors for the resources it needs for growth. This work describes the development of a model to predict the maximum growth rate in stem basal area of Eucalyptus pilularis Smith trees in native and plantation forests of subtropical eastern Australia. It shows maximum growth rates increasing with size until the tree reaches a stem diameter at breast height of 27 cm. Thereafter, maximum growth rates decline progressively as the tree grows larger. Physiological reasons that might describe this growth pattern are discussed. The maxima are shown to be independent of tree age, stand stocking density or average tree size, and the productive capacity of the site on which the forest is growing. Study Implications The maximum possible growth rate in stem diameter of a Eucalyptus pilularis tree growing in subtropical eastern Australia is found to depend only on tree size, not its age nor the productive capacity of the site on which it is growing. It increases until stem diameter reaches a certain size and decreases progressively thereafter as the tree continues to grow. There are interesting physiological reasons that may explain this pattern of growth.

scholarly journals Modelling the growth rate of Listeria monocytogenes in cooked ham stored at different temperatures

2017 ◽  
Vol 61 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Jacek Szczawiński ◽  
Małgorzata Ewa Szczawińska ◽  
Adriana Łobacz ◽  
Michał Tracz ◽  
Agnieszka Jackowska-Tracz
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Goodness Of Fit ◽  
Storage Temperature ◽  
Growth Curves ◽  
Information Criterion ◽  
Model Fit ◽  
Bacteria Growth ◽  
Cooked Ham ◽  
Different Temperatures

AbstractIntroduction:The purpose of the study was to determine and model the growth rates ofL. monocytogenesin cooked cured ham stored at various temperatures.Material and Methods:Samples of cured ham were artificially contaminated with a mixture of threeL. monocytogenesstrains and stored at 3, 6, 9, 12, or 15°C for 16 days. The number of listeriae was determined after 0, 1, 2, 3, 5, 7, 9, 12, 14, and 16 days. A series of decimal dilutions were prepared from each sample and plated onto ALOA agar, after which the plates were incubated at 37°C for 48 h under aerobic conditions. The bacterial counts were logarithmised and analysed statistically. Five repetitions of the experiment were performed.Results:Both storage temperature and time were found to significantly influence the growth rate of listeriae (P < 0.01). The test bacteria growth curves were fitted to three primary models: the Gompertz, Baranyi, and logistic. The mean square error (MSE) and Akaike’s information criterion (AIC) were calculated to evaluate the goodness of fit. It transpired that the logistic model fit the experimental data best. The natural logarithms ofL. monocytogenes’mean growth rates from this model were fitted to two secondary models: the square root and polynomial.Conclusion:Modelling in both secondary types can predict the growth rates ofL. monocytogenesin cooked cured ham stored at each studied temperature, but mathematical validation showed the polynomial model to be more accurate.

Growth rates of juvenile southern rock lobster (Jasus edwardsii) estimated through a diver-based tag - recapture program

2012 ◽  
Vol 63 (2) ◽  
pp. 110 ◽  
Author(s):  
Adrian Linnane ◽  
David Hobday ◽  
Stewart Frusher ◽  
Caleb Gardner
Keyword(s):  
Growth Rates ◽  
South Australia ◽  
Individual Growth ◽  
Rock Lobster ◽  
South Eastern ◽  
Growth Increments ◽  
Eastern Australia ◽  
Significant Difference ◽  
Jasus Edwardsii ◽  
South Eastern Australia

Despite being one of the most economically important fisheries in south-eastern Australia, growth rates of juvenile southern rock lobster (Jasus edwardsii) have not previously been quantified in the wild. This study utilised a diver-based tag–recapture program to estimate growth rates of individuals between 40–80 mm carapace length (CL) in temperate reef sites across south-eastern Australia. Of the 7064 lobsters tagged and released, 978 (14%) were recaptured with recapture rates of 23, 5 and 7% in the States of Tasmania, South Australia and Victoria respectively. Although individual growth increments were similar between the sexes, differences in annual growth rates were evident at 50 mm CL, with males growing ~1.4 times faster than females. Increased levels of growth in males resulted from a higher moult frequency, which was found to significantly reduce in females as they reached sexual maturity at ~70–80 mm CL. No significant difference was found in growth rates of males or females between the States when all sites within each State were combined. The growth estimates from this work contribute to the understanding of juvenile lobster population dynamics and will improve current fishery models by confirming relationships between early juvenile, pre-recruit abundance and entry to the fishable biomass.

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