• Ocean and Polar Research
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• v.44 no.1
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• pp.39-59
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• 2022

How in the Antarctic icefish, generally, and Pseudochaenichthys georgianus, in particular, otoliths increase in size and build new material as the fish ages and passes through different life phases is largely unexplored. Morphometric details of 3418 otoliths of Ps. georgianus from S. Georgia and 318 from S. Shetland, were processed and proportions of the amounts of collagen and aragonite removed by EDTA were determined for different age groups. Microstructural investigations showed that characteristics of the 3-dimensinal collagen net are the reason for the radial direction and orientation of the aragonite needles of approximately 1.0 ㎛ in length in larval and 2.3 ㎛ in length in adult specimens. Earlier generated increment layers from the primordial centre (PC) in the dorsal direction restrict those of the secondary centre (SC), causing new growth layer accretion in different directions. In the otoliths of larval Ps. georgianus, aragonite layers are 0.89 ㎛ wide while in juveniles and adults they measure 1.45-2.86 ㎛. Otoliths change from a sphere shape in the larvae to a longish object of irregular outline in the older stages. It is tentaively suggested that the observed otolith shape differences at distinct growth stages are due to physical effects related to swimming speeds at particular water depths and locations. To confirm that otoliths, apart from being useful for age analyses, could also serve to establish correlations between developmental stage and the oceanic environment the fish spend time in, further analyses using additional species and state-of-the-art methods like µCT imaging to evaluate otolith volumes and shapes are required.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.6-18
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• 2001

Larvae of the gunnel Pholis fangi were collected in coastal waters off Daecheon with a bag net from March to June, 1988, and with a ring larva net in February 1989. Maturity and spawning period were analyzed by examination of the gonads of adult fish collected with a bag net from May 1998 through November 1999. In February, the larvae were widely distributed in the outer and inner Cheonsu Bay. From March to April the larvae were present mainly the inner bay; they were absent there in May and found mainly in the outer bay. After June, few gunnel larvae were collected in the study area. This suggests a seaward movement of gunnel from the nursery grounds of the bay to offshore feeding grounds. The otolith of larvae smaller than 10 mm in total length did not show a distinct growth stop. The growth stop is believed to be formed in the early larval stage when the total length is about 10 mm. This period coincides with the time of shoreward migration, suggesting a metabolic change during this period. At a total length of 30 to 40 mm, the shape of the otolith changes from spherical to elongate. Daily growth rate in length was estimated by the Gompertz equation, which is represented as follows: TL = 6.702exp{2.925"1-exp (-0.008 t)"} ($r^2=0.94$, N = 92) Assuming daily deposition of growth increments in the otolith, the time of first growth increment formation was shown to be from December to January. Gonad observations show that Pholis fangi spawns from November to December. So, the hatching time is thought to be about one month.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.208-209
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• 2006

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.35-41
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• 2015

The age and growth of the Marbled sole, Pleuronectes yokohamae were investigated using left sagittal otoliths of 832 individuals collected in the mid-southern waters of Korea from January 2006 to April 2007. The seasonal changes in the ratio of an translucent zone to interval between annular rings revealed that the boundaries between translucent and opaque parts of the otolith were annual growth rings formed between May and June once a year. The spawning period was November to March and therefore the duration from fertilization to the complete formation of the annual growth ring became fifteen months. The parameters of von Bertalanffy growth equations estimated using the average standard length at each age are the $L_{\infty}$ of 48.04cm, K of 0.1406/year and $t_0$ of -0.5116 for female and 26.14cm, 0.3056/year and -0.8202 for male, respectively. Finally, it is suggested that the growth of female is faster than that of male from age-2.

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.177-183
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• 1993

Results comparing the scale and otolith ages for walleye pollock from the Donut Hole of the Bering Sea showed a significant discrepancy for fish older than 8 years old. For walleye pollock from the Shelikof Strait of the Gulf of Alaska, comparison between ages determined from the scale and otolith readings indicated that there were no differences for younger age groups, but for the ages 6 and older, discrepancies squeezed in somewhat amid the same age groups.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.1
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• pp.51-56
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• 2004

Age and growth of three-lined tonguefish (Cynoglossus abbreviatus) were studied using samples from the waters off Yosu, Korea, from June to December, 2001. Sagittal otoliths had relatively clear annuli. Each annulus was formed once a year in April. The peak of the gonadosomatic index occurred also in April. The oldest fish observed in this study was 5 years old for females and 4 years old for males. The relationship between the otolith radius (R) and total length (L) was as follows: L=14.921R-2.5318 for females and L=13.527R-0.5584 for males. The relationship between total length and body weight (W) was as follows: $W=0.0008L^{3.54}$ for females and $W=0.0029L^{3.14}$ for males. The growth in length of the fish was expressed by the von Bertalanffy's growth equation as: $$L_t=44.54(1-e^{-0.16(t+2.69)})\;for\;females\;and\;L_t=41.52(1-e^{-0.15(t+3.34)})\;for\;males$$.

• Korean Journal of Ichthyology
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• v.7 no.2
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• pp.171-176
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• 1995

Age and growth of Dictyosoma burgeri, sampled in the costal waters off Sanyang, Tongyeong, Ky$\breve{o}$ngnam during December 1992∼November 1993, were studied by otolith reading. Examination of outer margins of the otolith showed that the opaque zone as annulus was formed once a year with being mainly configured in November. Spawning period was estimated from January to March, with a peak in Feburary. Growth of the fish was expressed by the von Bertalanffy's equation as $L_t=23.5977(1-e^{-0.2542(t+2.1302)})$, $W_t=64.5892(1-e^{-0.2542(t+2.1302)})^{2.3002}$, where $L_t$ is total length in ㎝, $W_t$ is total weight in g and t is age.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.3
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• pp.261-269
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• 2013

The age and growth of the Pacific cod, Gadus macrocephalus were investigated using left sagittal otoliths of 682 individuals collected in the West Sea of Korea from January to December 2007. The seasonal changes in the ratio of an opaque zone to interval between annular rings revealed that the narrow translucent parts of the otolith were annual growth rings formed between February and March once a year. The spawning period was December to January and therefore the duration from fertilization to the complete formation of the opaque zone became thirteen months. From the parameters calculated using the average length when the year ring was formed, the estimated von Bertalanffy growth equations were $L_t=100.0(1-e^{-0.1640(t+0.5247)})$ for females and $L_t=64.6(1-e^{-0.3335 (t+0.3342)})$ for males when is total length in age t.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.650-655
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• 2019

The age and growth of Muraenesox cinereus collected in the South Sea of Korea by Danish seine and coastal Long-line fisheries were determined from right sagittal otoliths between May 2018 and April 2019. Otoliths of 353 fish were observed under reflected light, and the edges of the opaque zone were considered to be the otolith ring. Monthly changes in the marginal index indicated that rings (opaque zones) were formed once a year from June to July. The estimated von Bertalanffy growth equation with growth parameters estimated from non-linear regression were L_t=138.37 (1-e^{-0.18(t+0.79)}) for females and L_t=99.00 (1-e^{-0.13(t+3.99)}) for males. The oldest female M. cinereus was 12 years old, and the oldest male was 8 years old.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.1
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• pp.36-40
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• 1989

The eels, Anguilla japonica, were reared in a tank with daily feeding for up to 97 days, and otoliths were regularly collected for the observation of their microstructures. Microscopic observation of the thin-sectioned otolith under dark field provided significant information on daily growth increments as well as the difference in visual contrast shown by the increments. Clearly defined elver mark formed during the metamorphosis from leptocephalus to the elver can be considered as the origin of the age for the sedentary yellow eel in continental water. The close correspondence between the number of increments outside elver mark and chronological age in days from the beginning of feeding indicates that increment deposition on a daily basis was initiated with the start of feeding for the sedentary yellow eel. Either 7 or 14 daily growth increments were grouped together into 2 alternative units, each distinguished by prominent checks or by visual contrast. The absence of any apparent environmental variations with 7 or 14 day period in the reared tank implies that the phase of the moon could be a zeitgeber for the endogenous rhythm.