Fitting the von Bertalanffy growth equation to polar bear age–weight data

1979 ◽  
Vol 57 (5) ◽  
pp. 1020-1025 ◽  
Author(s):  
Michael C. S. Kingsley
Keyword(s):  
Polar Bear ◽  
Canadian Arctic ◽  
Growth Curves ◽  
Simplex Algorithm ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Direct Minimization ◽  
Males And Females ◽  
Von Bertalanffy Growth Equation ◽  
Weight Data

Heavy sea ice in the Canadian Arctic in the winter of 1973–1974 reduced seal populations; polar bears, preying principally on seals, consequently lost weight. The nature and degree of this weight loss was investigated by examining the parameters of von Bertalanffy growth curves, fitted by direct minimization of a sum of squares using the simplex algorithm of Nelder and Mead. Growth rates were lower for both males and females tagged in 1974–1975 than for bears tagged in 1971–1973. Weights of mature bears were unaffected.

Age and growth studies of Gummy Shark, Mustelus antarcticus Gunther, and School Shark, Galeorhinus galeus (Linnaeus), from Souther Australian Waters

1992 ◽  
Vol 43 (5) ◽  
pp. 1241 ◽  
Author(s):  
PL Moulton ◽  
TI Walker ◽  
SR Saddlier
Keyword(s):  
South Australia ◽  
Growth Curves ◽  
Growth Patterns ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Fishing Mortality ◽  
Male And Female ◽  
Length Data ◽  
Von Bertalanffy Growth Equation ◽  
Galeorhinus Galeus

Age-length data were derived from counting stained bands on whole vertebral centra obtained from gummy shark, Mustelus antarcticus, captured by gill-nets during 1973-76 in Bass Strait and from gummy shark and school shark, Galeorhinus galeus, captured during 1986-87 in Bass Strait and waters off South Australia. The data were fitted to the von Bertalanffy growth equation after adopting the Francis reparametrization and correcting for sampling bias caused by the selectivity effects of the gill-nets of various mesh sizes used to capture the sharks. The von Bertalanffy growth curves of male and female gummy shark were significantly different, but the growth curves of male and female school shark were not. The growth curves suggest that growth rates of male and female gummy shark in Bass Strait were lower during 1986-87 than during 1973-76 and that the growth rates of male and female gummy shark and school shark in Bass Strait during 1986-87 were lower than those in South Australia at the same time. These apparent temporal and spatial differences in growth patterns of gummy shark are explained by the 'Phenomenon of Apparent Change in Growth Rate'. It is concluded that the growth curves determined for 1986-87 are distorted by the effects of a long history of high and length-selective fishing mortality and that actual growth patterns of gummy shark are better represented by the von Bertalanffy growth equation determined for shark caught in Bass Strait during 1973-76, when fishing mortality was much lower. Verification of age estimates was attempted by comparing von Bertalanffy growth curves derived from age-length data with those derived from tag release-recapture length-increment data, but these comparisons highlight the limitations of using tag data for this purpose. Although reasonable agreement was found between such growth curves for gummy shark, it appears that school shark older than 11 years cannot be aged accurately from stained whole or sectioned vertebrae. Sectioned vertebrae from a school shark recaptured 35.7 years after being tagged and released and calculated as having an age exceeding 45 years gave estimates of only 18-20 years of age.

Good and bad fishing areas for Haliotis laevigata: A comparison of population parameters

1995 ◽  
Vol 46 (3) ◽  
pp. 591 ◽  
Author(s):  
FE Wells ◽  
P Mulvay
Keyword(s):  
Shell Length ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Population Parameters ◽  
Southern Coast ◽  
Close Inspection ◽  
Maximum Proportion ◽  
Males And Females ◽  
Von Bertalanffy Growth Equation ◽  
Mature Size

On the southern coast of Western Australia, proportionately more reproductive specimens of greenlip abalone, H. laevigata, were of legal size in 'good' fishing areas than in 'bad' fishing areas. Sex ratios were usually 1:1. Maturation of the gonads began at a size of 70-90 mm shell length (SL) and by 100-110 mm SL all animals were reproductively mature. Size-specific fecundities were not statistically different among the four good fishing areas examined, nor were they between the two bad fishing areas, but size-specific fecundity was greater in good than in bad fishing areas. Spawning begins as soon as the animals are mature; there is no gap between apparent histological maturity and actual spawning. Gonads are quiescent in the first part of the calendar year. Development is rapid in August and September, when animals begin to reach ripe condition. A maximum proportion of ripe animals occurs in October and November, followed by spawning in December. There was no difference between growth rates of males and females in either the good or the bad fishing areas. The von Bertalanffy growth equation disclosed no difference in growth between good and bad fishing areas, but close inspection of the data suggested that slower growth did occur in the bad fishing areas. The abalone reach reproductive maturity at an age of 2.5 to 3 years and the legal size of 140 mm SL at 5 to 6 years.

BODY TEMPERATURE AFFECTS THE SHAPE OF AVIAN GROWTH CURVES

1993 ◽  
Vol 01 (04) ◽  
pp. 363-374 ◽  
Author(s):  
C. ZONNEVELD ◽  
S.A.L.M. KOOIJMAN
Keyword(s):  
Body Temperature ◽  
Growth Curve ◽  
Time Course ◽  
Growth Curves ◽  
The Body ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Gradual Development ◽  
Mathematical Equations ◽  
Von Bertalanffy Growth Equation

Growth of birds is described by a variety of mathematical equations. These equations generally lack a biological motivation. As a result, it remains unclear why growth in different species should be described by different equations. In this article, we argue that the gradual development of endothermy affects the growth of birds. Hence, differences in the growth curve may result from differences in the thermal ontogeny. We assume that birds would grow according to the von Bertalanffy growth equation, if their temperature were constant. Using the deviations from this growth curve, we reconstruct the time course of the temperature of growing birds. This reconstruction well describes data on the ontogeny of the body temperature in birds.

Age and growth of Freshwater Herring, Potamalosa richmondia Macleay (Clupeidae: Hyperlophinae), in the Bellinger River, NSW

1989 ◽  
Vol 40 (6) ◽  
pp. 679 ◽  
Author(s):  
RWJ Pidgeon
Keyword(s):  
New South ◽  
Age And Growth ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Age Classes ◽  
South Wales ◽  
Marginal Increment ◽  
Males And Females ◽  
Von Bertalanffy Growth Equation ◽  
One Year

The freshwater herring, Potamalosa richmondia Macleay, is a catadromous fish that inhabits coastal rivers of New South Wales. Estimates of the age and growth of this species in the Bellinger River were made from scales. Comparison of scale ages with those from whole otoliths and burnt otolith sections from a sample of 30 fish aged at 2 to 8 years resulted in a 73 and 79% exact agreement and a 97 and 100% agreement within one year, respectively. Marginal-increment analysis of the scales indicated that the annulus was formed during the winter, which is also the spawning season. The ageing method was validated for age classes of 2 to 8 years by these procedures. The age at the first annulus and at ages 9 to 11 years could not be validated. The oldest fish examined was estimated to be 11 years old. The growth rate was very slow in comparison with that of other clupeids. Parameters of the von Bertalanffy growth equation, based on lengths and ages at capture, were L∞ = 252.7 mm, K = 0.126, and t0 = -2.77 years. There was no difference between the sexes in their growth in length. However, the length-weight relationships of males and females were different, with females longer than 180 mm weighing more than males of the same length. The predicted weights at the asymptotic length were 213.2 g for males and 257.6 g for females.

scholarly journals Age and growth of franciscana dolphins, Pontoporia blainvillei (Cetacea: Pontoporiidae) incidentally caught off southern Brazil and northern Argentina

2010 ◽  
Vol 90 (8) ◽  
pp. 1493-1500 ◽  
Author(s):  
Silvina Botta ◽  
Eduardo R. Secchi ◽  
Mônica M.C. Muelbert ◽  
Daniel Danilewicz ◽  
Maria Fernanda Negri ◽  
...  
Keyword(s):  
Growth Models ◽  
Growth Curves ◽  
Small Sample ◽  
Age And Growth ◽  
Buenos Aires Province ◽  
Von Bertalanffy ◽  
Southern Brazil ◽  
Data Set ◽  
Males And Females ◽  
Pontoporia Blainvillei

Age and length data of 291 franciscana dolphins (Pontoporia blainvillei) incidentally captured on the coast of Rio Grande do Sul State (RS), southern Brazil, were used to fit growth curves using Gompertz and Von Bertalanffy growth models. A small sample of franciscanas (N = 35) from Buenos Aires Province (BA), Argentina, were used to see if there are apparent growth differences between the populations. Male and female franciscana samples from both areas were primarily (78–85%) <4 years of age. The Von Bertalanffy growth model with a data set that excluded animals <1 year of age provided the best fit to data. Based on this model, dolphins from the RS population reached asymptotic length at 136.0 cm and 158.4 cm, for males and females, respectively. No remarkable differences were observed in the growth trajectories of males and females between the RS and BA populations.

Age, growth, and mortality of littlehead porgy, Calamus proridens, from southeast Florida coastal waters

2021 ◽  
Author(s):  
Michael L Burton ◽  
Jennifer C Potts ◽  
Ariel J Poholek ◽  
Jordan Page
Keyword(s):  
Coastal Waters ◽  
Southeastern United States ◽  
Fork Length ◽  
Total Mortality ◽  
Point Estimate ◽  
Growth Equation ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Recreational Fisheries ◽  
Von Bertalanffy Growth Equation

Sectioned otoliths were used to age littlehead porgy Calamus proridens (n = 737) from southeastern Florida recreational fisheries. Otolith sections contained easily identifiable annuli and were reliable structures for aging littlehead porgy up to 11 yrs. Opaque zones were deposited from March to June (peaking in April). Littlehead porgy ranged from 1 to 11 yrs and 220 to 385 mm total length (TL). Body size relationships were TL = 1.09 FL + 16.06 (n = 3474, r2 = 0.95), FL = 0.87 TL – 1.15 (n = 3474, r2 = 0.95), W = 4.76 × 10 −5 TL2.80 (n = 6722, r2 = 0.86), and W = 1.2 × 10−4 FL2.71 (n = 3474, r2 = 0.90), where W is total weight (g) and FL is fork length (mm). Growth was not significantly different between two discrete geographic regions of Florida, and the von Bertalanffy growth equation was Lt = 335 (1 − e−0.41 (t + 2.13)) for all areas combined. The point estimate of natural mortality was M = 0.38, while age-specific estimates of M ranged from 0.60 to 0.41 yrs−1 for ages 1–11. Littlehead porgy were fully recruited to the headboat fishery by age-3 and catch curve analysis resulted in an estimate of total mortality Z = 1.08 for ages 3–7+. This study reports first estimates of life history parameters for littlehead porgy from Atlantic waters of the southeastern United States.

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