• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.121-126
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• 1998

This study is to examine the energy budget of Hexagrammos agrammus in the natural habitat, based on the von Bertalanffy's growth model using food consumption and growth data of the fish. The fish were collected at the coasts of Tongbaek Island in Pusan and Shinsu Island in Samchonpo, Korea. The standard energy budget model was adopted for this study and the model has the components of toed consumption (C), production (G), assimilation (A), absorption ($A_b$), catabolism (R), excreta (U) and feces (F). These components were expressed as mass unit, not as calorie unit as usual. Both the mass and the proportion of each component varied with age of the fish, The mass of annual excreta declined as the fish became older, while those of the other components increased with the age. The relationship between mean weight (W) and annual absorption ($A_b$) was a non-linear one with the equation of $A_b=4.592W^{0.666}$, while that between mean weight (W) and annual catabolism (R) was linear as R=0.007+0.567W. On the other hand, the annual food consumption (C) showed linear relations both with annual assimilation (A) and annual catabolism (R) as A= -7.026+0.061C and R=-20.749+0.048C, respectively.

• The Korean Journal of Malacology
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• v.23 no.1
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• pp.17-23
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• 2007

Samples of Potamocorbula ustulata ustulata were collected monthly from October 2004 to November 2005 in the Jujin estuary of Gochang, Chollabuk-do, west coast of Korean peninsula. Age of P. ustulata ustulata was determined by the rings on the shell. The relationship between the shell length and the ring diameter in each ring group was expressed as a regression line. Therefore, there is a correspondence in each ring formation. Based on the monthly variation of the marginal index (MI') of the shell, it is assumed that the ring of this species was formed once a year during October to December. The relationship between the shell length (SL) and the shell height (SH; mm) was highly correlated with shell height as the following equation: SH = 0.6438 SL + 0.5642 ($r^2\;=\;0.978$). The shell length (SL) - shell width (SW) relation was also expressed by the following equation: SW = 0.4352 SL - 0.5675 ($r^2\;=\;0.957$). Shell length (SL; mm) and the total weight (TW; g) followed: $TW\;=\;6.999\;{\times}\;10^{-5}\;SL^{3.2542}(r^2\;=\;0.975)$. Growth curves for the shell length and the total weight fitted to the von Bertalanffy's growth curve were expressed respectively as: $$SL_t=30.77[1-e^{-0.4572(t+0.7371)}],\;TW_t=4.87[1-e^{-0.4572(t+0.7371)}]^{3.2542}.$$

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.4
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• pp.152-157
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• 2006

Samples of Meretrix lusoria were collected monthly from the tidal flat of Simpo, Puan-gun, Chollabuk-do, west coast of Korea from April 2004 to March 2005. Age of M. lusoria was determined from the rings on the shell. The relationship between shell length and ring radius in each ring group was expressed as a regression line. Therefore, there is a correspondence in each ring formation. Based on the monthly variations in the marginal index (MI') of the shell, it is assumed that the ring of this species was formed once a year during the period of February to April. The relationship between shell length (SL) and shell height (SH; mm) was highly correlated with shell height as the following equation: SH = 0.8103 SL + 0.5145 $(r^2=0.991)$. The shell length (SL) - shell width (SW) relation was also expressed by the following equation: SW = 0.4897 SL + 0.0315 $(r^2=0.976)$. Shell length (SL; mm) and total weight (TW; g) was expressed by the following equation: $TW=2.9195\times10^{-4}\;SL^{2.9547}\;(R^2=0.991)$. Shell length (SL) and shell height (SH; mm) was highly correlated with shell height as the following equation: $SH=0.8103\;SL+0.5145\;(R^2=0.991)$ The shell length (SL) - shell width (SW) relation was also expressed by the following equation: $SW=0.4897\;SL+0.0315\;(R^2=0.976)$. Growth curves for shell length and total weight fitted to the von Bertalanffy's growth curve were expressed respectively as: $SL_t=104.9[l-e^{-0.2235(t+0.7677)}],\;TW_t=280.8[l-e^{-0.2235(t+0.7677)}]^{2.9547}$.

• 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 $L_t=542[1-{\exp}\{-0.493 (t+0.769)\}]$.

• Korean Journal of Environment and Ecology
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• v.25 no.6
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• pp.861-866
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• 2011

Using skeletochronology in the Daejung-eup, Jeju, we determined the age structure of Kaloula borealis. The study was performed during the breed season in June 2009. We measured the snout-vent length(SVL) and body weigth(BW) and analyzed the age structure of 38 male and 58 female frogs. The mean value of SVL is $43.69{\pm}3.44mm$ in males and $46.32{\pm}4.23mm$ in females. The age at first reproduction was estimated to be 2 years of age in males and 3 years in females. The oldest males and females were 8 and 10 years of age, respectively. Therefore, the longevity in this species was estimated to be more than 8 years for males and 10 years for females. So, females live longer than males. Also, this difference between the male and the female in age structure was significant. We estimated the growth curve for Kaloula borealis using von Bertalanffy growth model. The growth coefficient (K) was 0.56 in male and 0.41 in female. The asymptotic size was 46.41 mm in male and 50.22 mm in female.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.133-141
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• 2015

Age and growth of redlip mullet, Chelon haematocheilus were determined using samples collected in Han River estuary of Korea from June, 2013 to May, 2014. Age was determined from sagital otoliths and Annul marks were formed in January once a year. In addition, spawning season was estimated in May, thus first ring was formed 8 months. The mullets were principally composed of 0 to 3 years old and the oldest was 9 years old. Relationship between standard length (SL) and total weight (TW) were $TW=0.0124SL^{3.0133}$($r^2=0.9931$). The Von Bertalanffy growth parameters estimated were $L_{\infty}$ 61.3, $W_{\infty}$ 3,230.6, K 0.29/year, $t_0$ - 0.05 year.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.222-233
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• 2000

A methodology for determining age by otolith of small yellow croaker, Pseudosoiaena polyactis Bleeker, was developed. A thin section method was chosen to be suitable for age determination because the otolith had a three-dimensional shape and thus it was not possible to read the otolith rings on the surface. The clear rings were identified on the vertical-axis cross-sectioned otoliths. The total length-total weight relationship and the growth parameters were estimated with error structure to endow with accuracy. In the relationship between total length and total weight, a multiplicative error structure was assumed because variability in growth increased as a function of the length, and the estimated equation was $W=0.0049L^{3.2153}$. The variability in growth was constant as a function of the age, revealing an additive error structure. The von Bertalanffy growth parameters were obtained from a nonlinear regression as $L_{\infty}= 37.11cm, K=0.20/yr and t_0=-1.88.$

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.234-243
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• 2000

This paper is to study population ecological characteristics, including growth parameters, survival rate, instantaneous coefficients of natural and fishing mortalities, and age at first capture of the soft-shelled clam, Mya japonioa in the intertidal zone of South Sea in Korea. For describing growth of the clam a von Bertalanffy growth model was adopted, The von Bertalanffy growth curve had an additive error structure and the growth parameters estimated from a non-linear regression were SH/sub ∞/=79.83mm, K=0.26, and t/sub 0/= -0.01. Survival rate (S) of the soft-shelled clam was 0.26 (SD=0.02). The instantaneous coefficients of natural mortality (M) was estimated to be 0.78/year and fishing mortality (F) 0.57/year for the soft-shelled clam. The age at first capture (t/sub c/) was estimated as 2.69 year. The mean densities of the soft-shelled clam by bottom type were 3.40 inds./m²(SE=0.18) in the sand, 63.4 inds./m²(SE= 0.53) in the muddy sand, and 0 inds./m2 (SE=0) in the gravelly sand. The mean densities of the soft-shelled clam by 3 different areas were 4.88 inds./m²(SE=0.09), 2.61 inds./m²(SE=0.13), 7.20 inds./m²(SE=0.18), respectively and the biomass of the clam were estimated as 131mt, 121mt, 665mt, respectively. An yield-per-recruit analysis showed that the current yield-per-recruit of about 8.30g with F=0.57/year and the age at first capture (t/sub c/) 2.69 year, was lower than the maximum possible yield-per-recruit of 9.60g. Fixing to at the current level and increased fishing intensity (F) could produce an increase in the predicted yield-per-recruit from 8.30g to about 9.40. However, estimated yield-per-recruit increased to 1.30g by decreasing to from the current age (2.69 year) to age two with F fixed at the current level. Yield-per-recruit was estimated under harvest strategies based on F/sub max/ and F/sub 0.1/.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.583-594
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• 2014

This study was performed to estimate biomass and provide management guidance through population ecological characteristics, including growth parameters, instantaneous coefficients of natural and fishing mortalities, and age at first capture of the starry flounder, Platichthys stellatus and olive flounder, Paralichthys olivaceus of Korea. For describing growth of this species, a von Bertalanffy growth model was adopted. The von Bertalanffy growth parameters estimated from a non-linear regression for starry flounder were $L_{{\infty}}=48.25cm$, K=0.16/yr, and $t_0=-1.48$, respectively and those for olive flounder were $L_{{\infty}}=86.46cm$, K=0.26/yr, and $t_0=-0.29$, respectively. Biomass of Platichthys stellatus was estimated by direct biomass estimation method was 2.6 M/T, that was estimated by indirect method was 13.4 M/Tt. Those of Paralichthys olivaceus were estimated as 10.1 M/T, 19.3 M/T, respectively. An yield per recruit analysis showed that the current yield per recruit on Platichthys stellatus was about 48.2 g with F=0.646/yr and the age at first capture ($t_c$) 1.35yr, that on Paralichthys olivaceus was about 167.6 g with F=1.121/yr and the age at first capture ($t_c$) 1yr.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.29-36
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• 1992

This paper deals with the estimation of population ecological parameters, including growth parameters, survival rates, instantaneous coefficient of natural mortality and age at first capture, of the small yellow-croaker, Pseudosciaena Polyactis in Korean waters, which determine fluctuations in stock abundance. For describing the growth of the small yellow croaker, von Bertalanffy growth equation was recommended for the purpose of stock assessment, although the Gompertz model yielded the closest fit. The survival rate (S) of the croaker was estimated to be 0.219 (variance=0.0000262), and the instantaneous coefficient of natural mortality (M) was 0.4 $year^{-1}$. From the estimates of S and M, the instantaneous coefficient of fishing mortality (F) was calculated to be 1.11$year^{-1}$ implying an impact from fishing three times that of natural mortality. Finally, the age at first capture $(t_{c})$ was estimated to be 0.602.