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

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.3
• /
• pp.222-233
• /
• 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
• /
• v.36 no.3
• /
• pp.234-243
• /
• 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/.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.3 no.3
• /
• pp.154-160
• /
• 1970

The present paper deals with the growth of yellow croaker by scale age reading. This study is based on material from 596 specimens caught by the Danish seine in the Yellow Sea during the period from June 1967 to April 1968. Ring marks of the scale were formed from April to July, corresponding to the spawning season of the fish reported by Bae (1960). Growth rate of each radius of the ring was approximately 0.73. The relationship between the total length and radius of scales, and the relationship between the body weight and total length are represented by the following equations respectively: L=61.350R+50.184 $$W=4.298L^{3.227}\times10^{-3}$$ Maximum total length calculated by the diagram of Walford's growth transformation, $$L_{n+1}=0.6866L_n+10.8730$$, was 346.9mm. Growth curve of the fish can be expressed by the following von Bertalanffy's equation : $$L_t=346.9(1-e^{-0.376(t+0.609)})$$

• Fisheries and Aquatic Sciences
• /
• v.15 no.4
• /
• pp.353-359
• /
• 2012

Age and growth of Hemibarbus labeo caught from Goe-san Lake in South Korea from March to November, 2011, were studied. A total of 201 specimens was collected, ranging from 110 to 580 mm in total length (TL). Males and females made up 47.9% and 52.1% of the sample, respectively. Marginal increment analyses showed that vertebral increments, each composed of one opaque and one hyaline zone, were deposited annually. Opaque edges were prevalent from June to July. The relationship between TL and vertebral radius was linear, with equations of R = 0.008TL - 0.208 (male) and R = 0.009TL - 0.272 (female). Regression equations between TL and total weight (TW) were $TW=9{\times}10^{-6}TL^{2.987}$ (male), $TW=8{\times}10^{-6}TL^{3.014}$ (female), and $TW=9{\times}10^{-6}TL^{2.988}$ (combined sexes), according to the von Bertalanffy growth equation. Back-calculated TL was expressed using the von Bertalanffy equation as follows: $L_t=438.25(1-e^{-0.175(t+0.164)})$ for males, $L_t=483.36(1-e^{-0.147(t+0.115)})$ for females, and $L_t=464.86(1-e^{-0.162(t+0.176)})$ for the sexes combined. The growth performances were 4.526, 4.536, and 4.544, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.2
• /
• pp.191-196
• /
• 1996

Age growth and spawning period of Enedrias nebulosus were estimated based on otoliths taken from a total of 255 fish samples of E. nebulosus, which were caught in the costal waters of $Kod\v{o}kto$ near Pusan from November 1990 to October 1991. Marginal increment analysis indicates that annuli in E. nebulosus are formed in December. Spawning period was estimated to be November to January, with a peak in December. The von Bertalanffy growth equations were expressed as follows: $L_t=33.64(1-e^{-0.1357(t+2.6853)})$ and $W_t=414.11(1-e^{-0.1357(t+2.6853)})^{3.9745}$, Where $L_t$, is total length in cm, $W_t$, is total weight in g and t is age in year.

• The Korean Journal of Malacology
• /
• v.21 no.1
• /
• pp.57-64
• /
• 2005

Samples of Corbicula japonica Prime of Jujin estuary in Gochang were collected from July 2000 to September 2001. Age of C. japonica 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 variation of 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 and March. The relationship between shell length (SL; mm) and total weight (TW; g) was expressed by the following equation: TW = 1.0942 ${\times}10^{-4}SL^{3.3217}$ ($r^2$ = 0.9905). Shell length (SL) and shell height (SH; mm) was highly correlated with shell height as the following equation: SH = 0.9174 SL - 0.9935 ($r^2$ = 0.9885). The shell length (SL) - shell width (SW) relation was also expressed by the following equation; SW = 0.5925 SL - 1.1706 ($r^2$ = 0.9726). Growth curves for shell length and total weight fitted to the von Bertalanffy's growth curve were expressed as: $$SL_t = 46.4861[1-e^{-0.3383(t+0.0958)}]$$, $$TW_t = 34.54[1-e^{-0.3383(t+0.0958)}]^3.3217$$.

• Korean Journal of Ichthyology
• /
• v.18 no.4
• /
• pp.355-362
• /
• 2006

The age and growth of brown sole, Pleuronectes herzensteini were investigated from samples randomly collected in the East Sea of Korea from April, 2003 to March, 2004. Ages were determined from annuli in otoliths and annuli were formed between March and May once a year. Also, main spawning period were estimated between March and April, thus rings were considered as annual marks. The von Bertalanffy growth parameters estimated from a non-linear regression method were $L_{\infty}=37.2cm$, K=0.131/year, $t_0=-2.008years$ for female and $L_{\infty}=28.3cm$, K=0.177/year, $t_0=-2.135years$ for male, and the growth between female and male was different.

• Ocean and Polar Research
• /
• v.43 no.2
• /
• pp.89-98
• /
• 2021

The seagrass habitats are a highly productive marine ecosystem which provides nursery ground and shelter for many fish and invertebrate species. Pholis nebulosa (Temminck & Schlegel, 1845) is one of the most abundant seagrass fishes in the coastal waters of Korea. The estimation of fish production is key for devising conservation measures and ensuring fish resources sustainability. A total 894 P. nebulosa ranging from 3.83 to 26.5 cm total length (TL) were collected monthly in 2006 with a small beam trawl in a seagrass bed of southern Korea. Growth parameters of P. nebulosa were estimated using the von Bertalanffy growth model, and production was estimated using a general equation which relates daily fish production to ash-free dry weight (AFDW), biomass, and water temperature. The von Bertalanffy's growth equation was estimated as: L_t = 28.3823(1-e^{-0.7835(t+0.9864)}). The densities, biomass, daily, annual production, and P/B ratio were 0.069±0.061/m^-2, 1.022±0.621 g/m², 0.005±0.004 g AFDW/m²/day, 1.676 g AFDW/m²/yr, and 1.641, respectively. Monthly variation in production of P. nebulosa peaked during March and April 2006 (0.0139 and 0.0111 g AFDW/m²/day), whereas the lowest value of 0.0005 g AFDW/m²/day was in December. Monthly change in production of P. nebulosa was positively correlated with biomass and condition factor. Our results will contribute to the conservation of seagrass ecosystems, which are still undisturbed in the study area.

• Korean Journal of Ichthyology
• /
• v.33 no.2
• /
• pp.64-73
• /
• 2021

We examined the growth and age structure for chub mackerel caught by a large purseseine in the Korean waters from January to December 2015. A total of 459 specimens were used for otolith analysis, ranging from 19.6 cm to 46.0 cm in fork length. Translucent zone was regarded as an annual mark, and age was counted using the information of the number of translucent zone, capture date, edge type of the otolith and nominal birthdate of 1 January. Annuli in otoliths were mainly formed in May, coinciding with the spawning season. Estimated ages were 0~6 years, and the von Bertalanffy growth models were not significantly different between male and female. Sex-combined growth model was obtained as FL_t=39.3×{1-exp[-0.90×(t+0.033)]}. Among the chub mackerel caught in 2015, the age 2 group had the highest proportion (30.9%), and the age 0 to 2 group accounted for 88.5% of the total catch.