A multifaceted approach to modelling growth of the Australian bonito, Sarda australis (Family Scombridae), with some observations on its reproductive biology

2013 ◽  
Vol 64 (7) ◽  
pp. 671 ◽  
Author(s):  
J. Stewart ◽  
W. D. Robbins ◽  
K. Rowling ◽  
A. Hegarty ◽  
A. Gould
Keyword(s):  
Fork Length ◽  
Maximum Growth ◽  
Austral Spring ◽  
Spawning Period ◽  
Growth Functions ◽  
Eastern Australia ◽  
Rate Maximum ◽  
Males And Females ◽  
Using Data ◽  
Size At Age

Growth of the Australian bonito, Sarda australis, is described for the first time using data from three different sources. Von Bertalanffy growth functions were fitted to: (1) size-at-age data derived from sectioned sagittal otoliths, (2) monthly length–frequency collections from a commercial line fishery, and (3) tag–recapture data from a long-term cooperative tagging study. Age estimates of S. australis were indirectly validated by examining the percentage of otoliths with opaque edges each month. The best-fitting growth functions for each data source yielded similar results, showing strong seasonal variations in growth rate. Maximum growth occurred during summer, with near cessation of growth apparent during winter. Early growth was very fast, with fish attaining ~30 cm fork length (FL) after 3–4 months. Growth of males and females was not significantly different. The oldest fish sampled was estimated to be 3+ years old, while the largest fish aged was 63.8 cm FL. Gonadosomatic indices indicated that S. australis has an austral spring/summer spawning period in eastern Australia. A preliminary estimate of the size at first sexual maturity was ~36 cm FL for both males and females, corresponding to an age of ~1 year.

Reproductive dynamics of broadbill swordfish, Xiphias gladius, in the domestic longline fishery off eastern Australia

2003 ◽  
Vol 54 (4) ◽  
pp. 315 ◽  
Author(s):  
Jock Young ◽  
Anita Drake ◽  
Michael Brickhill ◽  
Jessica Farley ◽  
Thor Carter
Keyword(s):  
New Zealand ◽  
Gonadosomatic Index ◽  
Fork Length ◽  
Reproductive Period ◽  
Fish Length ◽  
Batch Fecundity ◽  
Spawning Period ◽  
Fish Size ◽  
Eastern Australia ◽  
Xiphias Gladius

The reproductive ecology of broadbill swordfish, Xiphias gladius, was evaluated based on 1437 fish (size range 50–300 cm orbital fork length [OFL]) caught in the domestic longline fisheries off eastern Australia and New Zealand between May 1999 and March 2001. Reproductive activity was assessed using histology, a gonadosomatic index, and maximum oocyte size. Males were significantly smaller than females and represented less than one third of the sampled fish. Sex ratio differed significantly with respect to fish size and time of year. Females began maturing at 150-cm OFL and spawned from September to March, with the greatest activity from December to February. Males matured at 90-cm OFL; ripe males were found from January to March, but also in May and October, suggesting an extended reproductive period. During the spawning period the proportion of spawning to inactive mature sized females was significantly higher in waters west of longitude 158°E than in waters to the east. Further to the east, samples taken from the New Zealand fishery showed no actively spawning fish during the main spawning period. Females were increasingly reproductively active as water temperature increased beyond 24°C and sea surface chlorophyll a decreased below 0.2 μg L–1. Batch fecundity was linearly related to fish length with a mean batch fecundity of 1.66 million oocytes for females ranging in size from 173- to 232-cm OFL. The presence of hydrated oocytes and post-ovulatory follicles (POFs) in the same ovaries indicated multiple spawnings. Depending on the time taken for POFs to degrade, these may have been daily at the height of the spawning season.

Growth and reproductive biology of tarwhine Rhabdosargus sarba (Sparidae) in eastern Australia

2008 ◽  
Vol 59 (12) ◽  
pp. 1111 ◽  
Author(s):  
Julian M. Hughes ◽  
John Stewart ◽  
Benjamin W. Kendall ◽  
Charles A. Gray
Keyword(s):  
Reproductive Biology ◽  
Fork Length ◽  
Maximum Size ◽  
Growth Function ◽  
Similar Rate ◽  
South Wales ◽  
Eastern Australia ◽  
The World ◽  
Rate Maximum ◽  
Marginal Increment

The growth and reproductive biology of the commercially and recreationally important sparid fish, tarwhine (Rhabdosargus sarba), was examined from the coastal waters of New South Wales (NSW), south-eastern Australia. Previous research on this species in other parts of the world has yielded conflicting results concerning its growth and reproductive biology. Age estimates were made by counting opaque zones in otolith sections. The method was validated by marking the otoliths of captive fish with alizarin complexone, and also by marginal increment analyses using otoliths from wild-caught fish. Both sexes grew at a similar rate. Von Bertalanffy growth function parameters were: L∞ = 26.40 ± 0.40 cm fork length (FL), k = 0.39 ± 0.02 year–1 and to = –0.56 ± 0.09 years. The maximum estimated age was 16.5 years. Spawning occurred from May to August with a peak in July. Both sexes matured at a similar size (L50 = 19.44 ± 0.15 cm FL), which was larger than the current minimum legal length in NSW. Ovotestes were identified in adult tarwhine and were confirmed by histological analyses. Results of this study provided evidence that tarwhine are likely to be rudimentary hermaphrodites in eastern Australia and are more similar in growth rate, maximum size/age, and reproductive biology to tarwhine from Western Australia than those from other parts of the world.

Growth rates of black caiman (Melanosuchus niger) in the Rupununi region of Guyana

2016 ◽  
Vol 37 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Peter Taylor ◽  
Fernando Li ◽  
Ashley Holland ◽  
Michael Martin ◽  
Adam E. Rosenblatt
Keyword(s):  
Growth Rates ◽  
Mark Recapture ◽  
Future Studies ◽  
Density Dependent ◽  
Males And Females ◽  
Using Data ◽  
Size At Age

We conducted a study of black caiman (Melanosuchus niger) growth rates using data from a long-term mark-recapture study carried out in the Rupununi region of Guyana between 2005 and 2015. In contrast to previous studies, growth rates of black caiman declined with increasing size and this decline occurred more rapidly for females. Size-at-age models predicted that males and females reach asymptotic sizes of 178.2-189.0 cm SVL and 140.1-143.4 cm SVL, respectively. Our results suggest that growth rates of black caiman in the Rupununi region follow the same general patterns as for other crocodilians, and that disparities with previous black caiman studies may be largely related to density-dependent factors, among other possibilities. However, future studies that include large black caiman of known ages are needed to validate our findings.

Size-At-Age Variability and Sexual Dimorphism of Morphometric Characteristics in the Late Ontogenesis of the Marsh Frog, Pelophylax Ridibundus (Anura, Ranidae), from Terrytory of Crimea

2019 ◽  
Vol 53 (4) ◽  
pp. 325-334
Author(s):  
V. N. Peskov ◽  
N. A. Petrenko ◽  
V. Yu. Reminnyi
Keyword(s):  
Age Groups ◽  
The Body ◽  
Adult Males ◽  
Morphometric Characteristics ◽  
Morphometric Characters ◽  
Mean Values ◽  
Marsh Frog ◽  
Males And Females ◽  
Size At Age ◽  
Linear Body

Abstract We study size-at-age and sexual variability of morphometric characteristics of the marsh frog. According to the size of the body, males were divided into three size-age groups (juvenis, subadultus, adultus), females — into four groups (juvenis, subadultus, adultus, adultus-I). We found that the chronological age of frogs (skeletochronology) does not always correspond to their biological age (size and proportions of the body). We noted that the semi-adult males are reliably larger than females by mean values of 26 studied morphometric characters. Males and females of “adultus” group do not differ by linear body size, significant differences were found in body proportions (7 characters). For the females of “adultus-I” group, the mean values of 26 characters are significantly larger than for “adultus” males. The results of our study showed that with the age of the marsh frog, the level of exhibition, directionality and structure of morphometric sex differences changes.

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.

Length–Weight Relationship for Pomfret

1972 ◽  
Vol 29 (7) ◽  
pp. 1079-1081
Author(s):  
J. I. Manzer
Keyword(s):  
Size Range ◽  
Fork Length ◽  
Mesh Size ◽  
Gulf Of Alaska ◽  
Single Equation ◽  
Covariance Analysis ◽  
Allometric Equations ◽  
Pooled Data ◽  
Weight Relationship ◽  
Males And Females

The length–weight relationship for 298 pomfret (Brama japonica) ranging in fork length from 30 to 49 cm, and caught in 1956 and 1957 in the Gulf of Alaska by gillnets varying in mesh size from [Formula: see text] (63 mm) to [Formula: see text] inches (133 mm) was examined. Covariance analysis of the data indicated that within years the length–weight relationship did not differ between males and females; and, on the average, both males and females of a particular length were significantly heavier in 1956 than in 1957. Allometric equations for each year based on data for sexes combined are considered more appropriate than a single equation based on pooled data. The equations relating weight in kilograms to length in centimeters, for 1956 and 1957, respectively, are[Formula: see text]and apply to the lower third of the known size range for pomfret in the Gulf of Alaska.

The sensitivity of Australian animals to 1080 poison. I. Intraspecific variation and factors affecting acute toxicity

1981 ◽  
Vol 8 (2) ◽  
pp. 369 ◽  
Author(s):  
J. C. Mcilroy
Keyword(s):  
Acute Toxicity ◽  
Intraspecific Variation ◽  
Factors Affecting ◽  
Eastern Australia ◽  
Vertebrate Pests ◽  
Breeding Condition ◽  
Different Populations ◽  
Males And Females

The calculated sensitivity (LD50) of a species to 1080 poison (sodium fluoroacetate), used for control of vertebrate pests, is affected by the experimental procedures employed. Variation can be minimized if the most obvious sources are avoided, as described in this paper. Very young mammals and female waterfowl in breeding condition may be more sensitive to 1080 than other members of their populations. No other substantial differences in sensitivity were found between males and females, immatures and adults, or within and between different populations of six species of birds and mammals in eastern Australia.

scholarly journals Trends in mortality from ill-defined causes among the elderly in Brazil, 1979-2013: ecological study

2016 ◽  
Vol 134 (5) ◽  
pp. 437-445 ◽  
Author(s):  
Davi Félix Martins Junior ◽  
Ridalva Dias Martins Felzemburg ◽  
Acácia Batista Dias ◽  
Tania Maria Costa ◽  
Pedro Nascimento Prates Santos
Keyword(s):  
Ecological Study ◽  
Temporal Trend ◽  
Health Indicators ◽  
The Elderly ◽  
Simple Linear Regression ◽  
Geographical Regions ◽  
Proportional Mortality ◽  
Males And Females ◽  
Using Data ◽  
Health Situation

ABSTRACT CONTEXT AND OBJECTIVE: Mortality measurements are traditionally used as health indicators and are useful in describing a population's health situation through reporting injuries that lead to death. The aim here was to analyze the temporal trend of proportional mortality from ill-defined causes (IDCs) among the elderly in Brazil from 1979 to 2013. DESIGN AND SETTING: Ecological study using data from the Mortality Information System of the Brazilian Ministry of Health. METHODS: The proportional mortality from IDCs among the elderly was calculated for each year of the study series (1979 to 2013) in Brazil, and the data were disaggregated according to sex and to the five geographical regions and states. To analyze time trends, simple linear regression coefficients were calculated. RESULTS: During the study period, there were 2,646,194 deaths from IDCs among the elderly, with a decreasing trend (ß -0.545; confidence interval, CI: -0.616 to -0.475; P < 0.000) for both males and females. This reduction was also observed in the macroregions and states, except for Amapá. The states in the northeastern region reported an average reduction of 80%. CONCLUSIONS: Mortality from IDCs among the elderly has decreased continuously since 1985, but at different rates among the different regions and states. Actions aimed at improving data records on death certificates need to be strengthened in order to continue the trend observed.

Association of Suicide Rates of Elderly Persons with Fertility Rates

2008 ◽  
Vol 102 (2) ◽  
pp. 369-376 ◽  
Author(s):  
Ajit Shah
Keyword(s):  
Social Integration ◽  
The Elderly ◽  
World Health Organisation ◽  
World Health ◽  
Elderly Persons ◽  
Fertility Rates ◽  
Suicide Rates ◽  
Proxy Measure ◽  
Males And Females ◽  
Using Data

A negative correlation between societal suicide rates and social integration has been reported, but rarely specifically examined for suicide rates of the elderly although suicide rates of elderly persons are among the highest. The associations of suicide rates of elderly persons and fertility rates for 81 countries were examined using data from the World Health Organisation and United Nations. Fertility rates were considered a proxy measure for social integration. Multiple regression analysis indicated that suicide rates for males and females in the age bands 65–74 years and 75+ years were independently (negative) correlated with fertility rates. Fertility rates, as a measure of social integration, may interact with, modify and mediate the effect of cultural factors on suicide rates of elderly persons.

Age, growth estimates for pink ling, Genypterus blacodes (Schneider), and gemfish, Rexea solandri (Cuvier), from Eastern Bass Strait, Australia

1989 ◽  
Vol 40 (2) ◽  
pp. 215 ◽  
Author(s):  
AF Withell ◽  
JWJ Wankowski
Keyword(s):  
Growth Parameters ◽  
Age And Growth ◽  
Frequency Method ◽  
Slow Growth Rate ◽  
Growth Functions ◽  
Significant Difference ◽  
Marginal Increment ◽  
Males And Females ◽  
Cent Error ◽  
Age Determinations

Age and growth were estimated from counts of otolith annuli for pink ling (Genypterus blacodes) and gemfish (Rexea solandri). Sections of otoliths were preferable for age determinations of pink ling, whereas whole otoliths were preferable for gemfish. Validation of the assigned age classes was not achieved. Petersen's length-frequency method was unsuccessful and marginal increment methods were unsuitable for the species studied. Growth of males and females did not differ significantly for either pink ling or gemfish. Both species had a relatively slow growth rate, had a moderately long life-span and could reach body lengths in excess of 1 m. Maximum ages of pink ling and gemfish were, respectively, 21 and 13 years. Mean length-at-age and the von Bertalanffy growth functions were estimated. For pink ling (all individuals combined), K = 0.095 and L∞ = 135.5 cm. For gemfish the best estimates were K = 0.153 and L∞ = 112.3 cm. Precision of age determinations made independently by two readers for pink ling and gemfish, respectively, was 65% and 95% within �1 annulus; average per cent error, respectively, was 4.7% and 3.1%. Paired t-tests on ages assigned to each species by the two readers indicated no significant difference between ages assigned to gemfish, but there was a significant, albeit unbiased, difference for ages assigned to pink ling. However, for pink ling, estimates of the growth parameters derived separately from age determinations by the two readers were virtually identical.

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