Age estimation of barracouta (Thyrsites atun) off southern New Zealand

2002 ◽  
Vol 53 (8) ◽  
pp. 1169 ◽  
Author(s):  
P. L. Horn
Keyword(s):  
New Zealand ◽  
Validation Study ◽  
Age Estimation ◽  
Growth Parameters ◽  
Age Determination ◽  
Von Bertalanffy ◽  
Commercial Catch ◽  
Frequency Distributions

Age determination of barracouta (Thyrsites atun) by counting translucent zones in whole otoliths was validated by examining the number of zones in otoliths from consecutive juvenile modes and following the progression of a strong year class in age-frequency distributions. Readings from whole otoliths, rather than otolith sections, do not result in under-ageing of this species. The ageing interpretation was supported by the progression of a length mode in commercial catch samples over 5 years. The available data indicated a wide variation in year class strengths between years, a characteristic that was very useful in the validation study. Von Bertalanffy growth parameters were calculated, separately by sex, for barracouta from the Southland shelf, New Zealand. Female barracouta reach a significantly larger size than males.

Age and stock structure of gemfish (Rexea solandri) in New Zealand waters

1999 ◽  
Vol 50 (2) ◽  
pp. 103 ◽  
Author(s):  
P. L. Horn ◽  
R. J. Hurst
Keyword(s):  
Growth Parameters ◽  
Age Determination ◽  
Natural Mortality ◽  
Stock Structure ◽  
Von Bertalanffy ◽  
Length Frequency ◽  
Frequency Distributions ◽  
The North ◽  
Spawning Areas

Age determination of gemfish by counting hyaline zones in otoliths was validated by following the progression of modes in length–frequency distributions and the progression of strong and weak year classes in age–frequency distributions. Length–frequency and otolith samples were examined from four areas (west Northland, east Northland and Bay of Plenty, Wairarapa coast, and the Stewart- Snares shelf). Age–frequency distributions and von Bertalanffy growth parameters were calculated and compared between areas. Two gemfish stocks are indicated on the basis of patterns of year class strengths, trends in commercial landings and likely spawning areas; one off the east and north of the North Island, and another off the west and south of the South Island. Estimates of natural mortality are presented for the two stocks.

scholarly journals Age estimation, growth and maturity of the European hake (Merluccius merluccius (Linnaeus, 1758)) from Iberian Atlantic waters

2003 ◽  
Vol 60 (5) ◽  
pp. 1086-1102 ◽  
Author(s):  
C Piñeiro ◽  
M Saínza
Keyword(s):  
Life History ◽  
Age Estimation ◽  
Growth Parameters ◽  
Grey Literature ◽  
Von Bertalanffy ◽  
Merluccius Merluccius ◽  
Consistent Manner ◽  
The Mean ◽  
First Maturity ◽  
European Hake

Abstract Difficulties in age estimation for hake (Merluccius merluccius) have hampered the assessment of stocks. Here, we describe new, agreed ageing criteria based on the interpretation of the pattern of otolith growth. Improved estimates of von Bertalanffy growth parameters, and new estimates of maturity ogive parameters and length–weight relationships for European hake from Iberian Atlantic waters are presented. The results came from a study carried out during 1996–1997 and provide the first published account of the main life history traits of Southern stock hake. von Bertalanffy growth parameters of males were L∞ = 70cm, K = 0.18 year−1, and t0=−0.97 year, and those of females were L∞ = 89cm, K = 0.13 year−1, and t0 = −1.15 year. Growth of sexes differed from age 3 onwards, with females being on average larger and heavier than males. The estimated total length (L, cm)–total weight (W, g) relationships were W=0.0132135L2.8134246 for males and W=0.0086471L2.942563 for females. Spawning took place from December to May with a peak in February. The mean length and age at first maturity were 32.8 cm at 2.5 years for males and 45 cm at 4.4 years for females. Application of new ageing criteria showed that otolith sections may be used to determine ages up to 5 years in a consistent manner. These results indicate that hake of the Southern stock grow at higher rates and mature earlier than previously considered. Summaries of hake's life history parameters from other marine regions are also presented in order to make information that belongs largely to the grey literature available.

Reproduction in the red-legged pademelon, Thylogale stigmatica Gould (Marsupialia : Macropodidae), and age estimation and development of pouch young

1994 ◽  
Vol 21 (5) ◽  
pp. 553 ◽  
Author(s):  
PM Johnson ◽  
K Vernes
Keyword(s):  
Age Estimation ◽  
Post Partum ◽  
General Pattern ◽  
Age Determination ◽  
Gestation Period ◽  
Growth Equation ◽  
In Captivity ◽  
In The Wild ◽  
The Mean

The reproduction of Thylogale stigmatica in captivity was studied and a predictive growth equation for age determination of the pouch young was developed. The general pattern of reproduction involved an oestrous cycle of 29-32 days, a gestation period of 28-30 days and a mean pouch life of 184 days. A post-partum oestrus and mating generally followed birth. Births were observed in all months in captivity, and from October to June in the wild. Mean age of weaning of young was 66 days following permanent pouch emergence, and the mean ages at maturity for females and males was 341 and 466 days, respectively.

scholarly journals Structure and population dynamics of the secondary burrower crayfish Procambarus acanthophorus from a tropical Mexican wetland

2016 ◽  
Vol 94 (7) ◽  
pp. 479-488
Author(s):  
J.A. Viccon-Pale ◽  
P. Ortega ◽  
L. Mendoza-Vargas ◽  
P. Castilla-Hernández ◽  
A. López-Cuevas ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Growth Parameters ◽  
Von Bertalanffy ◽  
Frequency Distributions ◽  
Structure And Dynamics ◽  
Von Bertalanffy Model ◽  
Cephalothorax Length ◽  
Flood Period ◽  
Class Dynamic

Catch size, sex ratio, structure and dynamics, as well as mortality, of a population of the secondary burrower crayfish Procambarus acanthophorus Villalobos, 1948, from tropical wetland La Mixtequilla, Veracruz, Mexico, were examined. Monthly samples were taken from artisanal commercial captures. A total of 2141 individuals were caught. Although the total female:male ratio was 0.86, variation in sex ratios have also been found in monthly catches. Monthly polymodal frequency distributions of cephalothorax length (CL) were analyzed by the Bhattacharya method. Population catches consisted of six CL classes. The CL-class dynamic may show adaptations to the flood period. Growth parameters were estimated using the von Bertalanffy model. For females, K = 0.39 year−1, CL∞ = 57.30 mm, [Formula: see text] = 3.11, and tmax = 6.73 years were found; it is appropriate that for males, K = 0.40 year−1, CL∞ = 59.00 mm, [Formula: see text] = 3.14, and tmax = 6.59 years were found. We also examined whether water temperature influences the catches or sex ratio.

scholarly journals Age estimation by tooth/pulp ratio in canines by peri-apical X-rays: reliability in age determination of Spanish and Italian medieval skeletal remains

2010 ◽  
Vol 37 (12) ◽  
pp. 3048-3058 ◽  
Author(s):  
Stefano De Luca ◽  
Inmaculada Alemán ◽  
Francesca Bertoldi ◽  
Luigi Ferrante ◽  
Paola Mastrangelo ◽  
...  
Keyword(s):  
Age Estimation ◽  
Age Determination ◽  
Skeletal Remains ◽  
Tooth Pulp ◽  
X Rays

Why is age determination of Baltic cod (Gadus morhua) so difficult?

2010 ◽  
Vol 67 (6) ◽  
pp. 1198-1205 ◽  
Author(s):  
Karin Hüssy
Keyword(s):  
Gadus Morhua ◽  
Age Determination ◽  
Zone Formation ◽  
Frequency Distributions ◽  
Daily Increment ◽  
Reading Frequency ◽  
Traditional Age ◽  
Age Reading ◽  
Baltic Cod

Abstract Hüssy, K. 2010. Why is age determination of Baltic cod (Gadus morhua) so difficult? – ICES Journal of Marine Science, 67: 1198–1205. The aim of this study was to evaluate the consistency of three methods for assigning annuli in adult Baltic cod otoliths. The methods examined were (i) daily increment patterns, (ii) opacity profiles, and (iii) traditional age reading. Frequency distributions of the distance from the nucleus to the different zones showed that the first annulus of traditional age reading missed the first zone of both increment and opacity methods, but overlapped with the second zone identified by these methods. This pattern did not continue over subsequent zones. Frequency distributions of increment patterns were similar to opacity patterns. However, within individual fish, the co-occurrence of overlap between the two patterns was random. In cases where there was overlap, translucent zone formation started just before the disappearance of visible increments. Overlap in 1 year did not necessarily lead to a consistent pattern the following year, and overlap was not influenced by sex or fish size. The results suggest that otolith opacity in Baltic cod is not associated with seasonal patterns in daily increment structure and that traditional age determination based on otolith opacity yields highly uncertain estimates of age.

Reproduction of the spectacled hare-wallaby, Lagorchestes conspicillatus Gould (Marsupialia: Macropodidae), in captivity, with age estimation of the pouch young

1993 ◽  
Vol 20 (1) ◽  
pp. 97
Author(s):  
PM Johnson
Keyword(s):  
Age Estimation ◽  
Age Determination ◽  
Gestation Period ◽  
Northern Australia ◽  
Normal Pattern ◽  
Widespread Distribution ◽  
Young Females ◽  
In Captivity ◽  
One Year

Lagorchestes conspicillatus has a widespread distribution across northern Australia. Observations were made on reproduction in captive animals and a key produced for age determination of pouch young. Females commence breeding at about one year of age and males when slightly older. Reproduction in this species involved an oestrous cycle of 30 days, a gestation period of 29-31 days and a mean pouch life of 152 days. A postpartum oestrus and mating following a birth was the normal pattern of reproduction.

A Comparison of Tooth Eruption and Wear and Dental Cementum Techniques in Age Determination of New Zealand Feral Pigs.

1992 ◽  
Vol 19 (6) ◽  
pp. 769 ◽  
Author(s):  
CMH Clarke ◽  
RM Dzieciolowski ◽  
D Batcheler ◽  
CM Frampton
Keyword(s):  
New Zealand ◽  
Age Determination ◽  
Tooth Eruption ◽  
Permanent Teeth ◽  
Dietary Factor ◽  
Feral Pigs ◽  
Wild Pigs ◽  
Dental Ageing ◽  
Strong Agreement

This study evaluates dental ageing techniques for feral pigs in northern South I., New Zealand. Ages of pigs were estimated by three techniques: tooth eruption and replacement on criteria calibrated from pen-reared American-bred European wild pigs; tooth eruption, development, and wear calibrated from known-age feral pigs from the study area; and annular growth in cementum of molariform teeth. All age estimations showed strong agreement with each other and with known ages. The eruption and replacement criteria were most useful for ageing pigs less than 30 months old, whereas the other two criteria were more suited to ageing pigs more than 30 months old. All permanent teeth of New Zealand feral pigs erupted 1-2 months earlier than in European and Malayan wild pigs, and permanent premolars erupted up to 4 months earlier than in Japanese wild pigs. Earlier eruption may reflect early onset of maturity in New Zealand pigs. The clarity of annuli observed varied between animals, but generally increased with age. Pigs from unforested habitat had a higher percentage of clearly defined annuli than those from forested habitat. This may be explained by a climatic or dietary factor.

scholarly journals Natural Growth and Mortality of the Golden Grey Mullet Liza Aurata (Risso, 1810) In the Lagoon of Klisova-Messolonghi (W. Greece)

2019 ◽  
pp. 23-31 ◽  
Author(s):  
George N. Hotos
Keyword(s):  
Growth Parameters ◽  
Age Determination ◽  
Growth Curves ◽  
Growth Function ◽  
First Year ◽  
Annual Growth Rate ◽  
Von Bertalanffy ◽  
Liza Aurata ◽  
Total Length ◽  
Von Bertalanffy Growth Function

Growth and mortality of L. aurata (Risso,1810) were estimated in the lagoon of Klisova-Messolonghi (W. Greece), based on age estimation from scale readings of a total of 1048 individuals, ranging between 10 and 59 cm in total length (TL). Age determination revealed nine age classes (0+ to 8+). Maximum age was found to be 8 years for females and 6 years for males respectively. The growth pattern of L. aurata exhibited allometry (b=3.26). The species seems to achieve 34% of its growth during the first year; thereafter the annual growth rate drops. Both sexes presented similar von Bertalanffy growth curves. The von Bertalanffy growth function for the estimated total length-at-age was found Lt = 70.78 [1 - e -0.129(t+1.345)] for the combined sexes. Otolith weight, length and width were tested and they were found to be very good predictors for age. Between the present L. aurata growth parameters and those of other Mediterranean, Caspian and Atlantic Sea for the same species, there were found significant differences in its growth parameters. The total (Z) and natural (M) mortality rate was found to be 0.54 years-1 and 0.33 years-1 respectively. The estimated exploitation rate was found to be E=0.395 which suggests that the existing fishing pressure on L. aurata is rather moderate in the investigated region.

scholarly journals Age determination of the adult blow fly Lucilia sericata (Diptera: Calliphoridae) through quantitative pteridine fluorescence analysis

2020 ◽  
Vol 16 (4) ◽  
pp. 641-648
Author(s):  
Ronja Estévez Dimitrov ◽  
Jens Amendt ◽  
Florian Rothweiler ◽  
Richard Zehner
Keyword(s):  
Age Estimation ◽  
Age Determination ◽  
Fluorescence Analysis ◽  
Lucilia Sericata ◽  
Head Width ◽  
Blow Fly ◽  
Fluorescence Level ◽  
Juvenile Stages ◽  
Set Up

AbstractDetermination of a minimal postmortem interval via age estimation of necrophagous diptera has been restricted to the juvenile stages and the time until emergence of the adult fly, i.e. up until 2–6 weeks depending on species and temperature. Age estimation of adult flies could extend this period by adding the age of the fly to the time needed for complete development. In this context pteridines are promising metabolites, as they accumulate in the eyes of flies with increasing age. We studied adults of the blow fly Lucilia sericata at constant temperatures of 16 °C and 25 °C up to an age of 25 days and estimated their pteridine levels by fluorescence spectroscopy. Age was given in accumulated degree days (ADD) across temperatures. Additionally, a mock case was set up to test the applicability of the method. Pteridine increases logarithmically with increasing ADD, but after 70–80 ADD the increase slows down and the curve approaches a maximum. Sex had a significant impact (p < 4.09 × 10−6) on pteridine fluorescence level, while body-size and head-width did not. The mock case demonstrated that a slight overestimation of the real age (in ADD) only occurred in two out of 30 samples. Age determination of L. sericata on the basis of pteridine levels seems to be limited to an age of about 70 ADD, but depending on the ambient temperature this could cover an extra amount of time of about 5–7 days after completion of the metamorphosis.

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