• Ocean and Polar Research
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• v.39 no.4
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• pp.279-292
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• 2017

We determined the maturity and growth of the Marbled sole, Pseudopleuronectes yokohamae based on monthly sampling in the West Sea of Korea from February 2009 to December 2010. Determination of sex of P. yokohamae was by gonadal inspection, and age and growth were determined by analyzing the otolith. The biological minimum size of P. yokohamae female was 24.5 cm. The seasonal changes in the ratio of a translucent zone to an opaque zone revealed that the end of the translucent zone of the otolith were annuli formed in May once a year. We compared 8 type growth equations with several length-at-age data. By using the length-at-monthly age data of these, the calculated von Bertalanffy growth equations were $L_t=41.7(1-e^{-0.47(t+0.24)})$ for females and $L_t=32.7(1-e^{-0.75(t+0.01)})$ for males. We estimated that 24.5 cm was the total length of 2 year old P. yokohamae spawns in the cold water season from January to April, and grows to 8 years old for females and 6 years old for males in the West Sea of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.583-589
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• 2022

The feeding habits of the marbled flounder Pseudopleuronectes yokohamae were studied using 384 specimens (10.7-52.3 cm in total length) collected from the West Sea, Korea between January and December 2021. P. yokohamae ate mainly polychaeta and gastropoda, incuding teleostei, caridea, euphausiacea, amphipoda and brachyura. The mean number of preys per stomach (mN/ST) showed a statistically significant difference, and the mean weight of prey per stomach (mW/ST) increased as the total length increased. P. yokohamae ate mainly teleostei in spring and winter. P. yokohamae ate mainly euphausiacea in summer and mainly polychaeta in autumn.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.367-375
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• 2016

Marbled flounder Pseudopleuronectes yokohamae is a commercially important flatfish in the coastal waters of the East Sea off Pohang, Korea. Maturity and spawning dynamics of P. yokohamae were investigated based on samples collected by gill net and long line in the coastal waters off Pohang from January 2013 to December 2014. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity, and total length at 50% group maturity. We found that the spawning period was December to February, wherein fecundity ranged from 55,760 eggs at 20.40 cm total length (TL) to 1,559,007 eggs at 46.6 cm TL. The relationship between TL and fecundity (F) was F = 0.0017 TL^3.5604 (R² = 0.6984), and F increased with increasing TL. We estimated the TL at 50% group maturity as 27.4 cm for female and 23.5 cm for male P. yokohamae, respectively. The results from this research will aid in the development of policies on season and minimum catch length for sustainable production of P. yokohamae. We propose that it is necessary to conduct long-term ecological monitoring for this species because biological properties such as spawning ecology and growth performance are being affected by climate change.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.278-286
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• 2017

The age and growth of marbled flounder Pseudopleuronectes yokohamae in coastal waters of the East Sea of Korea off Pohang were determined, by evaluating monthly samples of commercial catches, caught by gill nets and longlines from February 2013 to January 2014. New annuli from annually in P. yokohamae otoliths, and the boundary between the opaque and translucent zones forms from March to May. The relationships between total length (TL) and total weight (TW) were $TW=0.009TL^{3.128}$ ($R^2=0.969$) for females and $TW=0.008TL^{3.150}$ ($R^2=0.964$) for males. The TLs at the time of annulus formation, back-calculated from the otolith-length relationship by reference to the von Bertalanffy growth curves, were $L_t=52.63$ ($1-{\exp}^{(-0.231(t+0.033))}$) for females and $L_t=36.22$ ($1-{\exp}^{(-0.400(t+0.117))}$) for males. Commencing at the age of 3 years, females grew faster than males (P<0.05).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.1
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• pp.35-40
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• 2014

Hatching date, main spawning period and growth of juvenile marbled flounder (Pseudopleuronectes yokohamae) were determined by analysis of microstructure in otoliths. Marbled flounders were collected by a small beam trawl in Namhae from February 2011 to January 2012. The length (L, mm) was related to body weight (W, g); $W=9.76^*10^{-8}L^{4.39}$ ($r^2=0.93$). The length was also related to otolith radius (R, ${\mu}m$); L=0.0795R+0.2249 ($r^2=0.92$). The growth in length was represented by Gompertz growth curve; $L_t=135{\exp}\{-{\exp}[0.0103(t-116)]\}$ ($r^2=0.83$). The hatching date calculated from the number of daily growth increments in otoliths was between mid-December and mid-February.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.156-163
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• 2024

This study investigated the temporal patterns of species composition and abundance of larval fish assemblages through seasonal samplings in the coastal waters off Uljin, East Sea from April 2022 to February 2023. A total of 27 taxa of larval fishes were collected in the study area. The dominant fish larvae were Pseudopleuronectes herzensteini, Sebastes inermis, Ammodytes japonicus, Pseudopleuronectes yokohamae, Rudarius ercodes and Parablennius yatabei constituting 86.6% of total larval fish abundance. The number of species, abundance, and diversity index fluctuated according to season, showing the highest species number and abundance in April (spring) and diversity in July (summer). Larval fish assemblages were divided into three seasonal groups, including spring, summer and winter groups based on relative abundance of each fish larvae. Among abundant fish larvae, P. herzensteini predominated during spring, while P. yatabei and R. ercodes were abundant during summer. S. inermis, A. japonicus and P. yokohamae constituted the most abundant larval fish group during winter. These temporal changes in larval fish assemblages were attributed to seasonal changes in surface water temperature. The results from this study may elucidate our understanding of larval fish diversity and contribute to evaluating the nursery function of coastal habitats in the East Sea.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.174-181
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• 2024

This study examines the community characteristics of fish species collected by fyke net from the eastern coastal waters of Yeosu, Korea, during the period from 2020 to 2021. A total of 4,539 fish were sampled and classified into 43 species, 28 families, and 7 orders. The dominant species included Mugil cephalus (14.4%), Konosirus punctatus (10.9%), Lateolabrax japonicus (8.3%), Acanthopagrus schlegelii (7.9%), and Pennahia argentata (7.2%). The diversity index was highest in October (H'=2.888) and lowest in February (H'=2.075). Furthermore, the dominance index was highest in March (DI=0.524) and lowest in December (DI=0.178). Hierarchical cluster analysis (HCA) revealed that fish communities could be divided into three groups based on Bray-Curtis similarity. Group 1, consisting mainly of species collected from June to October, formed one cluster. Group 2, including winter spawning species such as Pseudopleuronectes yokohamae, Clupea pallasii, and Hexagrammos otakii, sampled from November to February, formed another cluster. Group 3, which included species such as Larimichthys polyactis, Amblychaeturichthys hexanema, and Sebastes inermis, formed a cluster collected from March to May. The eastern coast of Yeosu is considered a suitable habitat for fisheries resources, including highly economically valuable species, and it is also assumed to be an important spawning and nursery ground for many fish species.

• Korean Journal of Ichthyology
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• v.30 no.1
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• pp.55-64
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• 2018

Fish assemblages in a sandy shore and an eelgrass bed were compared based on monthly samples in the southern coastal water of Korea. Samples were collected by a beam trawl in the sandy shore and a surf net in the eelgrass from March to February 2012. The common fish species were Syngnathus schlegeli, Pseudoblennius cottoides, Pholis nebulosa, Favonigobius gymnauchen, Gymnogobius heptacanthus, Pseudopleuronectes yokohamae, Takifugu niphobles. Among them S. schlegeli, Urocampus nanus, P. cottoides, P. nebulosa, T. niphobles were high abundance in the eelgrass bed than in the sandy shore, whereas Acanthogobius flavimanus, Acentrogobius pflaumi, F. gymnauchen, G. heptacanthus, P. yokohamae were high in the sandy shore. Aulichthys japonicus, Hippocampus coronatus, Sebastes inermis, Lateolabrax japonicus, Siganus fuscescens were found in the eelgrass bed, and Thryssa hamiltoni, Mugil cephalus, Inimicus japonicus, Platycephalus indicus, Hexagrammos otakii, Furcina ishikawae, Liparis tanakae, Repomucenus curvicornis, and Eutaeniichthys gilli were observed in the sandy shore. Species composition and abundance varied seasonally in two habitats; The number of species and abundance was high in August and September, while biomass was the highest in April and September. Fish numbers as well as biomass were lowest in February. Number of individuals and biomass of fish in the eelgrass bed were significantly higher than those of in the sandy shore. Some fish preferred to live in the eelgrass were collected in the sandy shore, while fish preferred to live in the sandy shore were rarely collected in the eelgrass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.947-959
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• 2015

Variations in the species composition, biomass and size distribution of fisheries resources in the Uljin marine ranching area were investigated using trammel nets at two stations (artificial reef and natural rocky area) from 2009 to 2010. During the survey, a total of 74 species were sampled with a mean density of 132 ind./net and mean biomass of 21.56 kg/net. In the natural rocky area, a total of 45 species were sampled at a mean density of 202 ind./net and mean biomass of 28.81 kg/net, while in the artificial reef area, samples included a total of 56 species, with means of 62 ind./net and 14.30 kg/net. The dominant species, comprising over 3% of the total number of individuals, were Suberites ficus (30.8%), Ovalipes punctatus (19.2%), Paralichthys olivaceus (11.7%), Pleuronectes herzensteini (4.7%), Kareius bicoloratus (3.5%), Pseudopleuronectes yokohamae (3.5%) and Eopsetta grigorjewi (3.0%). The dominant species, in terms of biomass, comprising over 5% of the total biomass, were P. olivaceus (22.1%), S. ficus (18.7%), O. punctatus (7.2%), Hexagrammos otakii (6.6%), P. yokohamae (5.7%), K. bicoloratus and P. herzensteini (5.3%). A cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on the Bray-Curtis similarity of fourth root transformed data for number of species and individuals, was divided into two groups: the artificial reef area (group A) and the natural rocky area (group B).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.335-348
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• 2019

We found ten species of larvae belonging to the family Pleuronectidae as a result of analysis on ichthyoplankton collected monthly from the East Sea, Yellow Sea, Korea Strait and East China Sea between February 2016 and May 2018 using bongo net. The ten species of pleuronectid larvae were divided into three groups in morphology. Group A had three or four bars on the lateral side of the tail: Glyptocephalus stelleri, G. kitaharae, Pseudopleuronectes yokohamae, and Hippoglossoides dubius. Group B had a row of melanophores along the dorsal and ventral side of tail: Cleisthenes pinetorum, Eopsetta grigorjewi, Dexistes rikuzenius, and Platichthys bicoloratus. Group C had dense melanophores which are covering trunk and tail entirely except caudal peduncle: Platichthys cornutus and Platichthys japonicus. The three groups did not associate with previous molecular phylogenetic studies except for the G. stelleri and G. kitaharae of the group A.