• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.194-201
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• 2014

Age and growth of flathead grey mullet Mugil cephalus were estimated using samples collected by a two-side fyke net in the coastal water off Taean in 2008. Age was determined by examination of annuli in otoliths and total lengths at ages were back-calculated from otolth-body size relationship. Total length ranged from 239 to 605 mm and mainly between 400 and 550 mm. Observed ages ranged from 1 to 7 years old and mainly between 3 and 5 years old. Total length (L, mm) was linearly related to otolith radius (R, mm); L=15.3+87.9 R. Total lengths at the annulus formation in otolith were back-calculated by Frazer-Lee method. Estimated length at the age 1 was $316{\pm}40.6mm$ ($mean{\pm}SD$) showing a fast growth rate during the early growth stage. Total length at each age (t) showed a wide range indicating the big difference in growth rate among individuals. Growth in total length can be expressed by a Von Bertalanffy growth curve as $L_t=542[1-{\exp}\{-0.493 (t+0.769)\}]$.

• Animal cells and systems
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• v.14 no.4
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• pp.315-322
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• 2010

We studied and compared the age structure, body size, and growth rates of field populations of two Korean salamander species (Hynobius yangi and Hynobius quelpaertensis) to elucidate important aspects of basic population dynamics of these two endemic Hynobius species. In both populations, females were sexually mature at three years of age, while H. yangi and H. quelpaertensis males matured at two and three years of age, respectively. Both males and females of H. yangi and H. quelpaertensis attained a maximum age of 11 years and 10 years, respectively. In both species, the snout-vent length (SVL) and body weight (BW) of the females were greater than those of the males. The SVL, BW, and asymptotic SVL of both male and female H. yangi were smaller than those of H. quelpaertensis. The adult growth rates after sexual maturation of male and female H. yangi were lower than those of H. quelpaertensis, possibly resulting in the smaller body size of the former, although overall growth coefficients were not significantly different between the two species. We also compared the age structure and growth rates of three Korean and three Japanese species of Hynobius.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.695-700
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• 2011

Age, growth, and maturity of Trichiurus lepturus were estimated based on right-handed sagittal otoliths belonging to 1,031 fish collected from January to December 2007 in the East China Sea. The outer margins of the otolith were examined and showed that an opaque zone was formed once per year. Marginal increments in otoliths formed as annual rings between June and August, at the beginning of the spawning season. Fish growth was expressed by the von Bertalanffy growth equation, as follows: $L_t=494.0$ ($1-e^{-0.2453(t+-0.4822)}$) for females and $L_t=330.4$ ($1-e^{-0.4292(t+0.7513)}$) for males, where $L_t$ is the total length in mm and t is age in years. The growth rates of males and females were significantly different (P<0.05).The age composition ranged mostly between ages 2 and 4, and the oldest individuals were 4 years old in males and 6 years old in females. Finally, the age composition of largehead hairtail was compared with data from the 1970s and is discussed in the context of environmental changes.

• Korean Journal of Health Education and Promotion
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• v.24 no.5
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• pp.69-85
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• 2007

Purpose: The purpose of this study is to clarify the traits of differences supposed as secular differences in physical growth between samples of children and youth in 1999 and 2005, and to identify the need of children and youth for health promotion. Methods: Two samples of different cohort were selected. The first one was consisted of 231 boys and 346 girls in 1999. And the other was consisted of 171 boys and 400 girls in 2005. Then the longitudinal growth distance data were collected from their cumulative health examination records. Results: The 2005 were larger in growth distances of stature, body weight, sitting height, and chest girth a at all ages from 6 to 16 in both boys and girls, so it could be concluded that a certain positive shift in growth process appeared in such a short duration. The 2005 were larger in growth velocity before peak age and also after peak age in body weight, but only in the term after peak age significant secular differences were found in stature for both sexes. As far as the growth distance concerned, the 2005 boys were ahead of the 1999 boys from 0.28-1.02 years and the 2005 girls from 0.32 to 0.81 years. In growth distance. Only in peak velocity, significant secular change was recognized in both sexes, any positive evidences of appearance of secular change were not found in peal age. In such derived physical indices as BMI, body weight index, sitting height index, and chest girth index, obvious evidences of secular change appearance were found.

• The Korean Journal of Ecology
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• v.21 no.3
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• pp.251-255
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• 1998

To elucidate the effects of a hydroelectric dam construction on annual ring growth of Pinus densiflora, the annual ring widths of 68 trees collected from 7 sites were closely examined. The result was analyzed to ask three special questions first, whether there are real effects of dam construction on the radial growth second, would the magnitude of the effect be different due to two periods of under-construction and post-construction the last, would it be different among age classes. Annual ring growth has been significantly enhanced by the dam construction. Specially, its effect was marked after the construction was finished and the reservoir was filled up with water. There was, however, no remarkable evidence that pine growth would be reduced while the dam was under construction, even though there was a minor decreasing trend. The magnitude of the effect was different among age groups. That is, the changed condition after the construction enhanced relatively the growth of aged trees monre. According to other meterological research since the dam was constructed, the reasons of enhancing pine growth assumed to be the increase of daily temperature, the decreased of daily temperature difference and the increased of rainy days.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.471-475
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• 2017

This study aims to suggest the methodology to improve to estimate back-calculated fish growth parameters using weighted average. It is to contribute to correct errors in the calculation of back-calculated growth equation with unequal numbers of sample by age. If the numbers of sample were evenly collected by age, each back-calculated length at age was equal between arithmetic and weighted averages. However, most samples cannot be evenly collected by age in reality because of different catchability by fishing gear and limitation of environment condition. Therefore, the estimation of back-calculated length by weighted average method is essential to calculate growth parameters. There were some published growth equations from back-calculated length using a simple arithmetic average with different numbers of samples by age when searching for back-calculated growth equations from 91 relevant papers. In this study, the process of deriving growth equation was investigated and two different average calculations were applied to a fish growth equation, for example of Acheilognathus signifer. Growth parameters, such as $L_{\infty}$, k and $t_0$, were estimated from two different back-calculated averages and the growth equations were compared with growth performance index. Based on the correction of back-calculated length using weighted average by age, the changes by female and male were -14.19% and -5.23% for $L_{\infty}$, and 59.28% and 18.91% for k, respectively. The corrected growth performance index by weighted average improved at 7.05% and 2.46% by female and male, respectively, compared to the arithmetic averages.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.3
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• pp.516-524
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• 1995

The purpose of this study was to analyze the variation of body shape and to. divide growth period into some age groups based on body type. Duncan Test, Heath-Carter's somatotyping method and allottery equation (y=baa) were applied to semiautomatic data concerning obesity/leakiness. The materials were 309 females aged from 12 to 17 years old. The following results were obtained: 1. In the Developmental trend of the human body, the 12-13 age groups belonged to the acceleration stage of adolescent growth spurt. The 14-15 age groups belonged to the latter period of adolescent growth. The 16-17 age groups belonged to the termination stage of adolescent growth. 2. In the Heath-Carter's somatotyping method, the average somatotype changed into M.M- C-C-M-D with age. 3. In the alphamerical analysis, the first critical point appeared at the stature 146 Cm in case of weight, LBM and fat. The second critical point appeared at the stature 154-157 Cm in case of LBM and Fat. All the three measurement showed positive allotmentty.

• The Korean Journal of Malacology
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• v.26 no.3
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• pp.227-234
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• 2010

A comparative analysis of size and age structures of coastal subfossil shell assemblages of the shortnecked clam Ruditapes philippinarum from open and protected bays of Cheju Island (Korea) was carried out. On the whole, taking into account the damage of small fragile shells, size and age structures of the shell assemblages corresponded to the classical curve of bivalve population distribution when its mortality diminishes with age increase up to a certain threshold. It was found that shell samples from open bays of the western, southern and eastern coasts included shells of smaller and younger individuals (L ${\leq}$ 40 mm, ${\leq}$ 4 years) than samples from the eastern protected bay (L ${\leq}$ 54.5 mm, ${\leq}$ 6 years). Evidently, strong wave activity was the reason for a short life-span of the clams from the open areas. Growth was investigated retrospectively by annual growth rings on the shells. Growth rates of the clams from the various coasts of Cheju Island differed. However, growth rates of the clams from different biotopes at the same (eastern) side of the Island were similar. Shell height/length and width/length ratios statistically significantly increased with the clam age increase. Most likely, the reason for such shell shape alteration is that more conglobated individuals more survive being more energy-optimal than oblong specimens.

• Journal of Korean Society of Forest Science
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• v.99 no.2
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• pp.213-219
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• 2010

Early results from a field trail of Agathis loranthifolia are reported from a progeny test of 100 open-pollinated families in west Java, Indonesia. The average of height and diameter at root collar (DRC) was 40.18 cm and 0.52 cm at age 15 months. Family survival rate ranged from 86.5% at age 10 months to 81.7% at age 15 months. Family means of 10 best and 10 poorest families for each trait indicated that there was a large difference of growth performances among individual families. For height and DRC growth, the poorest groups had averages of 33.98 cm and 0.43 mm while the averages of the best groups were 47.35 cm and 0.62 mm at age 15 months as a difference of 39.36% and 43.65%, respectively. Differences between the best group and the test population mean, which is the selection differential, were implying that genetic gain from selection for the improvement of height and DRC growth would be achieved. The family variances of DRC and height were relatively small compared to replicate and residual variances. Family heritabilities for both studied traits were fluctuated, and the genetic coefficients of variation for DRC and height at age of 15 months were 7.19% and 5.22%, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1281-1285
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• 2004

A line of Japanese quail selected for increased body weight for 15 generations (C) and an unselected control line (K) were used to examine the impact of selection for body weight on the growth curve of Japanese quail. In addition, the effect of sex on the growth curve in each line was also studied, namely females of C (CF), males of C (CM), females of K (KF) and males of K (KM). The monophasic and diphasic growth models were studied for adequacy in describing growth curves of quail in both sexes of the C and K lines. The monophasic function provided almost the same growth rate for both sexes in both lines. However, the growth rates calculated by means of the diphasic function differed between sexes for both lines, except for those calculated for C during the second growth phase. While there were 2-3 days difference between sexes in age at maximum gain in both lines with a monophasic model, the difference between sexes in the age at maximum gain in both lines became greater according to the diphasic model. There were 5 and 7 days difference between sexes in the age at maximum gain in line C for the first and second growth phases, respectively. A difference between sexes of 18 and 11 days in the age at maximum gain for the first and second phases, respectively, was estimated for line K when the diphasic function was fitted. The use of diphasic functions provides more detailed information on growth patterns. The results showed that the use of the diphasic function was better because it provided greater insights into understanding the biology of growth.