• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.648-656
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• 2016

The age and growth of jack mackerel Trachurus japonicus caught by large purse seine fishery were studied during August 2004 and May 2005. Otoliths of 472 fish were observed under reflected light, and translucent zones made on the post-rostrum axis were regarded as annual marks. Monthly changes in the marginal index indicated that the translucent zone was formed once a year, mainly in March-April, which was coincident with the peak spawning time of jack mackerel. The estimated ages were 0-6 years, corresponding to a fork length (FL) range of 13 to 38 cm. Most obtained individuals were 2-year-old fish, followed by 1-year-old fish. The mean fork length at age from otolith reading (sex combined) was applied to the von Bertalanffy equation and growth parameters were estimated: L_∞ = 38.29 cm FL, k = 0.31 years⁻¹, t₀ = −0.81 years.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.144-150
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• 2003

Reproductive biology and population dynamics of Latreutes planirostris were investigated on the south western waters of Korea from June 2001 to May 2002. This paper describes sex ratio, population growth, and reproductive aspects of Latreutes planirostris. Brood size was an isometric function of female carapace length. Based on dry weight, reproduction effort (mass of eggs/mass of female) averaged 0.23. Ovarian examination showed that there was significantly higher gonadosomatic index from May to September, with a peak in June. Statistical analysis revealed that the ovarian dry weight of females with eyed eggs was significantly higher than that of those with non-eyed eggs. This suggests that females were potentially consecutive breeders. Sex ratio showed that female is more numerous than male. Growth parameters mortality and recruitment were estimated by monthly length-frequency data. Growth parameters were estimated, using the seasonalized von Bertalanffy growth function model $(L\infty\;=\;12.70\;mm\;CL,\;K\;=\;0.87yr^{-1},\;C\;=\;0.96,\;WP\;=\;0.59)$. The recruitment pattern was twice a year.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.2
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• pp.129-140
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• 2008

This study was performed to estimate biomass and to provide management plan through population ecological characteristics, including growth parameters, survival rate, instantaneous coefficient of natural and fishing mortalities, and age at first capture of hen clam, Mactra chinensis, in the Dong-li self-regulatory community of Busan. The von Bertalanffy growth parameters estimated from a non-linear regression were $SH_{\infty}=86.24mm$, K=0.12/year, and = -1.37year. Survival rate(s) of the hen clam was 0.515. The instantaneous coefficients of natural mortality(M) was estimated to be 0.232/year and fishing mortality(F) 0.432/year for hen clam. The current biomass of the hen clam in the study area was estimated to be 713mt and the acceptable biological catch(ABC) was estimated under various harvest strategies based on $F_{0.1}$ and $F_{40%}$.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.2
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• pp.169-175
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• 2014

The age and growth of rabbit fish, Siganus fuscescens were investigated from samples monthly collected in the coast of Jeju island, Korea from February to December 2012. Ages were determined from annuli in otoliths, and annuli were formed in one or two months immediately after spawning once a year. Also, main spawning period was estimated between July and August, thus rings were considered as annual marks. The von Bertalanffy growth equations estimated from a non-linear regression method were $L_t=37.24(1-e^{-0.33(t+1.24)})$ ($R^2=0.92$) for female and $L_t=31.44(1-e^{-0.45(t+1.23)})$ ($R^2=0.90$) for male, and the growth between female and male was different.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.646-653
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• 2003

Investigations were made on the population structure, sex ratio, growth, and recruitment patterns of Leptochela sydniensis in the southwestern coastal areas of Korea, between May 2000 and December 2001. Spawning period, fecundity, brood loss, reproductive output, and size at sexual maturity also were examined. The results of the sex ratio showed that females were more numerous than males during the overall study period. Parameters of growth were estimated using the modified von Bertalanffy growth function (VBGF) model incorporating seasonal variation into growth. Females grew somewhat faster and reached a larger size than males $(L\infty=12.80\;mm\;CL\;and\;K=0.70\;yr^{-1}\;or\;females,\and\;L\infty=12.08\;mm\;CL\;and\;K=0.69\;yr^{-1}$ for males). The structure of recruitment patterns obtained by the FiSAT program indicated one normally distributed group. Based on the occurrence of ovigerous females and the gonadosomatic index (GSI), the main spawning season was from June to August. Analysis of covariance indicated that brood loss was not observed during the incubation period. The size at which $50\%$ of females are mature is estimated as 5.48 mm CL.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.557-562
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• 2002

This study was to estimate population growth parameters of the freshwater bivalve, Corbicula (Corbiculina) papyacca (Heude) in Korea. Samples were collected from Jojong stream in Chungpyeong from September 1999 to August 2000. Ages were determined from the ring of shell, The shell length of the samples ranged from 4,2 mm to 28.1 mm, The ring on the surface of shell was formed once a year from January to March, Marginal increment analysis of shell rings indicated that annuli were formed in June. Spawning period was estimated to be May to August with a peak between June and July through fatness analysis, and thus rings were considered to be true annual marks. Von Bertalanffy's growth parameter were estimated from a nonlinear method with the value of logical maximum shell length ($L_{propto}$) was 34,36 mm, K was 0.1531/year, logical age of shell length 0 ($t_{0}$) was -0,5246 year, and logical maximum total weight ($W_{propto}$) was 11.42 g.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.307-311
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• 2004

Age and growth of red tongue sole (Cynoglossus joyneri), were studied using samples from the coastal waters off Yeosu, Korea, from January to December, 2001. Sagittal otoliths had relatively clear annuli. Marginal index of otolith dropped sharhly in August suggesting that each annulus was formed once a year In August. Monthly changes in the gonadosomatic index indicated that spawning peaked between July and September. The oldest fish observed in this study was 4 years old for both of females and males. Relationships between the otolith radius (R) and total length (L) were: L=14.1R-0.098 for females, and L=11.9R+1.83 for males. Relationships between total length and body weight $(W)\;were:\;W=0.0021L^{3.24}\;for\;females,\;and\;W=0.0014L^{3.39}$ for males. Growth in length of the fish was expressed by the von Bertalanffy's growth equation as:$L_{t}=29.06\;(1-e^{-0.19(t+2.40)})\;for\;females\;and\;L_{t}=27.44 (1-e^{-0.17(t+2.84)})$ for males.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.372-379
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• 2024

The small yellow croaker Larimichthys polyactis is an important ecological and commercial species in the waters of Korea. Based on samples purchased monthly from a market from 2019 to 2021, except during the closed season, we analyzed the age and growth of the small yellow croaker using 894 otoliths. The total lengths of the small yellow croaker ranged from 12.0 to 38.9 cm, which is a sufficient length range for analyzing age structure and growth parameters. The translucent zone, formed during the spawning season in June, was counted as the annual mark. The estimated ages were 0-10 years, and the 38.9 cm individuals were 7 years old, while the 34.2 cm individuals were 10 years old. The highest proportion in this study (86.8%) was 0-3 years. The von Bertalanffy growth model was obtained as L_t=41.2(1-exp-^0.20(t+1.50)).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.364-371
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• 2024

We studied the age and growth of anchovies Engraulis japonicus, collected using three different fishing gears (drag net, set net, and bottom trawl) in the South Sea of Korea from November 2020 to October 2021.To determine the age, 344 speciemens were analyzed by reading the otolith sagittal plane. Monthly changes in the growth of translucency at the edge and the marginal increment ratio revealed that annuli in otoliths were fully formed in March once a year. We compared four different types of growth equations, and found that the data set of observed length at age (yearly) as estimated the growth parameter (L_∞ = FL 16.17 cm, k = 0.33/year, t₀ = -1.65) fitted well on the von Bertalanffy growth curve.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.537-545
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• 1996

A population study on the sternaspid polychaete Sternaspis scutata (Ranzani) was conducted in Chinhae Bay, Korea, from lune 1987 to May 1990. Sternaspis scutata was chiefly distributed in the mouth area of the bay, and its distributional delimitation remained unchanged all the year round. Abundance of this species appeared to be related to the organic carbon content of the sediment. It was relatively high in the area where the organic content of the sediment was between 2.0 and $4.0\%(mean\;3.8{\pm}1.11)$ with mean grain size of $8.75\phi$. The relationship between the length of the ventral plate and the body wet weight is Wt=13.2752 $L^{2.7984}(R^2=0.962)$. Therefore, the length of ventral plate can be used as an indicator of body growth of this species. The growth curves fitted to yon Bertalanffy equations for ventral plates and weights are $L_{t}=5.235(1-e^{-0.3625(t-0.4047)})$ and $W_{t}=1364.1(1-e^{-0.3625(t-0.4047)})^{2.7984}$, respectively. Size frequency histograms showed that the settlement occurred during all the year round with its peak in summer.