• 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 Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.550-555
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• 1999

The growth and spawning time of juvenile Ammodytes personatus were analyzed based on the daily growth increment in otolith reading of the sample caught in the coastal waters of Shinsudo, Sacheon from March 20 to May 1, 1988. Daily growth increment in otolith was formed once a day. The estimated spawning time ranged from November, 1987 to March, 1988. The von Bertalanffy growth model and the Gompertz growth model were expressed as, $TL=87.80(1-e^{-0.0074(t+10.79)})$ and $TL=72.59 e^{-1.8417\;e-0.0152t}$ respectively, where TL is total length in mm, t is age in day.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.31-36
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• 2021

In order to understand the age and growth characteristics of Pacific anchovy, Engraulis japonicus, the 506 otoliths of individuals collected in the southern waters of Korea in 2004 were analyzed. Monthly age of anchovies was estimated based on the age determined through the year rings and their collection date. The growth parameters obtained using the monthly folk lengths were a theoretical maximum body length of 132.9 mm, a growth coefficient of 0.1079/month and a theoretical age of 0.0262 month when the fork length is zero. The growth equation of von Bertalanffy presented by the growth parameters was L_t=132.9(1-e^{-0.1079(t-1.0262)}). The estimation of growth parameters based on the monthly age established through year ring and collection date was deemed appropriate for understanding the growth characteristics of anchovies.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.82-90
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• 2010

The ecological characteristics of the Korean Aucha perch, Coreoperca herzi, were determined in order to estimate stock of the mid-upper system of the Seomjin River. The age was determined by counting the otolith annuli. The oldest fish observed in this study was 5 years old. Relationships between body length (BL) and body weight (BW) were $BW=0.0195BL^{3.08}$ ($R^2=0.966$) (p<0.01). Relationships between the otolith radius (R) and body length (BL) were BL=3.882R+1.66 ($R^2=0.944$). The von Bertalanffy growth parameters estimated from a non-linear regression method were $L_{\infty}=19.68\;cm$, $W_{\infty}=188.64\;g$, $K=0.17\;year^{-1}$ and $t_0=-1.46$ year. Therefore, growth in length of the fish was expressed by the von Bertalanffy's growth equation as $L_t=19.68$ ($1-e^{-0.17(t+1.46)}$) ($R^2=0.997$). The annual survival rate (S) was estimated to be $0.666\;year^{-1}$. The instantaneous coefficient of natural mortality (M) of estimated from the Zhang and Megrey method was $0.346\;year^{-1}$, and instantaneous coefficient of fishing mortality (F) was calculated $0.061\;year^{-1}$. From the estimates of survival rate (S), the instantaneous coefficient of total mortality(Z) was estimated to be $0.407\;year^{-1}$.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.377-380
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• 2001

The vestibular system located in the inner ear controls reflex body posture and movement. It has the semicircular canals sensing an angular acceleration and the otolith organs sensing a linear acceleration. With this organic signal, medical doctor decide if a person has disease or not. To obtain this data, a precision stimular system is considered. Robust control is needed to obtain eye signals induced by off-vertical axis rotation because of an unbalanced load produced by tilting the axis of the system upto 30 degrees. In this study, off-vertical axis rotatory system with visual stimulation system are developed. This system is consisted of head mounted display for generating horizontal, vertical, and three dimensional stimulus patterns. Furthermore wireless recording system using RF modem is considered for noiseless data transmission.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.324-332
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• 2019

In this study, the possibility of a follow-up study on environmental pollution in domestic freshwater was identified by analyzing fish otoliths using Laser ablation-inductively coupled mass spectrometry (LA-ICP/MS). Fish otolith are known to be affected by the environment in which fish live. As a result, research on this subject is active in many countries; however, this is not the case in Korea. Therefore, in this study, the possibility of tracing environmental pollution using fish otoliths was identified by analyzing the components of metal elements used as indicators for environmental pollution. For the component analysis of metallic elements LA-ICP/MS, which can shorten analysis time by reducing the pretreatment process, was used. Sampling was conducted by dividing the research and the background area and carp, a freshwater species, was selected as the experimental fish species subject. Based on the established LA-ICP/MS conditions, the concentration of the metallic elements in the fish otoliths collected in the research area was 2202.9 mg kg^-1, 2.03 times higher than the 1,086.3 mg kg^-1 in the background area. All elements except for Li and U, were found to be higher in the research area than in the background area. Compared with the sediment measuring net analysis data, the distribution tendency of Zn, Pb, and Cu in sediment metal element concentrations in the two regions and distribution of metal element concentration in fish otoliths were similarly shown. These results confirm that fish otoliths can be used to track environmental pollutants, such as in sediments.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.176-189
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• 2017

Age estimation and sexual dimorphism of Coreoleuciscus splendidus were estimated using otolith, length-frequency distribution and 23 morphological measurements, from 245 individuals collected from September 2016, February and April 2017 in the Gapyeong stream, Han River, Korea. Result of age estimation of C. splendidus, we most examined were 2, 3 and 4-age, and the maximum observed ages were 5-age. Nine out of twenty-three morphometric measurements were significantly different between the genders. Anal fin have showing major sexual dimorphism in particular between adult individuals. This sexual dimorphism was based on extension of anal fin soft rays of male individuals. Therefore anal fin of males is always longer and wider than females. During spawning season male individuals possess nuptial tubercles on anal fin rays. However, another measurements and morphological characters does not exhibit sexual dimorphism in the between male and female individuals. The sexual dimorphism was observed to only over 2-years old individuals with sexual maturity. But juvenile and 1-years old individuals do not have sexual dimorphism with sexual maturity. Peak season of spawning was April to May and they start first spawning at 2-age. The ages at major spawning groups were most 3-age, and they maximum GSI index was 14.91 (female), 8.96 (male) at 5-age, respectively.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.110-117
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• 2012

Hatching date and early growth of Pacific cod Gadus macrocephalus were estimated by examination of otolith microstructure of Pacific cod juveniles collected in Jinhae Bay of Korea from May to June, 2008. Water temperature during the main spawning time ranged from 7 to $9^{\circ}C$ according to the geographic distribution of temperature measured from November to May between 2006 and 2009. The spawners were collected from December to February between 2006 and 2008, and the gonadosomatic index of spawners was larger in females than in males, showing a peak in January. Total length of juveniles ranged from 37.5 to 94.9 mm ($63.2{\pm}11.0mm$; mean${\pm}$SD). The number of daily growth increments in juvenile otoliths were on average $102{\pm}15$ in May 17 samples, $119{\pm}16$ in May 29 ones and $116{\pm}18$ in June 3 ones. Hatching dates estimated from the number of daily growth increments ranged from late December to mid-March, showing the peak between late January and mid-February. Daily growth in total length (TL, mm) can be adjusted to the Gompertz curve: $TL_t=123.2{\exp}\{-{\exp}[-0.0165(t-81.8)]\}$ ($r^2$=0.93, n=273).

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.269-277
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• 2011

Age and growth pattern of Pacific cod Gadus macrocephalus were determined using samples collected in Jinhae Bay in Korea during the spawning period from 2006 to 2009. The ages of 333 specimens were estimated using their otoliths. The reliability of scales as a means of age determination was analyzed by comparing the ages estimated from otoliths and scales of 96 specimens. The scales collected from the base of the second dorsal fin or from the caudal peduncle were proved to be suitable for age determination of Pacific cod. Monthly changes in the marginal index in otoliths decreased from December showing the lowest value in February. Ages ranged from 4 to 6 years for both females and males, and most of them were 6 years old. Relationships between the otolith radius (R) and total length (TL) were TL=10.4R+3.1 for males, and TL=11.5R+3.4 for females. The growth curves in total length ($L_t$, cm) were expressed as $L_t$=141.5 [1-exp{-0.089 (t+0.209)}] for males and $L_t$=127.5 [1-exp {-0.124 (t+0.077)}] for females.

• Korean Journal of Ichthyology
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• v.8 no.2
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• pp.16-22
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• 1996

Age and growth of Epinephelus akaara were determined using samples collected from the south western sea of Korea. Thin - sectioned otoliths showed relatively well defined annuli when examined under dark - field microscope. Because the fish do not feed at the temperature under $10^{\circ}C$, the annuli in otoliths are considered to be formed during the period between December and April. Considering that the peak spawning season is July, the first annulus must have been formed in 0.5 year after birth. The oldest fish examined was 9 years old, and the largest one was 47cm. The body length(L, cm) was linearly related to the otolith radius (R, ${\mu}m$) : L= - 2.84+7.01 R. Back-calculated lengths for each age using the relationship between body and otolith size were well adjusted to the Von Bertalanffy growth curve : $L_t$=55.5[1-exp{-0.162(t+0.128)}]. Using relationship between length and weight ($W_t$=0.00608$L^{3.21}$), growth in weight was expressed by Wt=2409(1-exp{-0.162(t+0.128)}]$^{3.21}$.