• Korean Journal of Ichthyology
• /
• v.32 no.2
• /
• pp.97-102
• /
• 2020

The feeding habits of larval Ammodytes japonicus were examined. A total of 208 individuals were collected by RN80 Net from January to February, 2019 in the coastal waters of Gujora and Mangchi, Geoje, Korea. Range of notochord length of larval A. japonicus was 1.46~8.00 mm and fed mainly on copepods that constituted 99.9% in %IRI. The results of analysis in ontogenetic changes, divided with 3 classes (≤2 mm, 3~4 mm, ≥5 mm, Notochord length), was all classes mainly fed copepods. An opposite relationship was found between the calanoida and cyclopoida. When percentage of calanoida of copepods increased, cyclopoida of copepods decreased.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.56 no.2
• /
• pp.94-104
• /
• 2020

An ecological study for species composition and abundance of the fish assemblages in the coastal waters of Gujora and Mangchi of Geoje, Korea was conducted using monthly larval collection by an RN80 net from June, 2018 to May, 2019. A total of the 5 Orders, 15 Families, 21 species were collected. The dominant species were Ammodytes japonicus and Engraulis japonicas. Gobiidae was the most dominant species in June, Spratelloides gracilis in July, Chelidonichthys sp. in August, Gobiidae in September, Repomucenus beniteguri in October, Sebastiscus marmoratus in November, Sebastiscus marmoratus and Hexagrammos otakii in December of 2018, Pleuronectes yokohamae in January, Ammodytes japonicus in Febraury, Engraulis japonicus in March, Sebastes sp. and Gobiidae in April and Engraulis japonicus in May of 2019. The highest number of species and individuals were found in July and the smallest in August. Thus, the diversity index was the highest in July and the lowest in August. As a result of the similarity by month was divided into Group I in January and February and Group II in April, June and September. The most dominant species in the Group I were the Ammodytes japonicus and Sebastes inermis, and the most dominant species in the Group II was Gobiidae.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.53 no.1
• /
• pp.19-26
• /
• 2020

The maturity and spawning of pacific sand eels Ammodytes japonicus, was investigated using samples collected by gill net in coastal waters near Donghae, Gangwon-do, from January 2017 to December 2018. Monthly changes were analyzed in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity (F), and total length (TL) at 50% group maturity. The average TLs of female and male A. japonicus were 18.5 and 18.1 cm, respectively. The spawning period was from November to March, with the peak from December to February based on monthly changes in GSI and maturity stages. The egg diameter during the spawning-capable stage was 300-1000 (main mode 500-600) ㎛. Fecundity ranged from 6,411 eggs at 16.7 cm fork length to 45,771 eggs at 24.7 cm fork length. The relationship between TL and F was F=0.00005TL^4.2715 (R²=0.7216), such that F increased with TL. TL at 50% group maturity was estimated to be 15.1 cm for both sexes.

• Fisheries and Aquatic Sciences
• /
• v.21 no.9
• /
• pp.20.1-20.3
• /
• 2018

Hypoptychus dybowskii, the Korean sandlance, is widespread in cold areas of the North Pacific. Although H. dybowskii has been considered to occur on the coast of Hamgyeongnam-do in Korea, the species is also distributed along the coast of Goseong-gun, Gangwon-do, south of Hamgyeongnam-do in the eastern part of the Korean Peninsula on the basis of newly collected specimens. In addition, many Koreans confuse H. dybowskii and Ammodytes japonicus (= A. personatus for Korean specimens) because the Korean common name or dialect of both species is "Yang-mi-ri", yet the two species differ in their external morphology. Hypoptychus dybowskii differs from A. japonicus in the location of the origin of the dorsal fin and the number of dorsal and anal fin rays.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.5
• /
• pp.654-664
• /
• 1998

Seasonal variation in species composition and abundance of pelagic fish in Chonsu Bay were determined by analyzing monthly samples collected using a set net from March, 1992 to January, 1993. The data in this study were compared with those of 1981$\~$82. Of 63 species identified, Engraulis japonicus, Ammodytes penonatus, Enedrias fangi and Sardinella zunasi predominated in abundance. Especially E.japonicus occupied $87\%$ of total number of individuals. In spling, fish abundance increased by recruitment of lariat E. fanti as well as adults of E. japonicus, A. personatus and S. zunasi. These adults moved towards the open sea after spawning in early summer. A large number of juveniles was then collected from August until December. The seasonal change in species composition from the present study showed a similar trend to that occurred in 1981$\~$82. However, larger number of pelagic fish was caught in 1992$\~$93 than in 1981$\~$82. This result seems to be related to the higher water temperature (>$2^{\circ}C$) than the average mean temperature in spring and autumn, implying that higher temperature provides favorable conditions for spawning and growth of the fish.

• Korean Journal of Ichthyology
• /
• v.36 no.2
• /
• pp.156-163
• /
• 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 Fisheries and Aquatic Sciences
• /
• v.36 no.2
• /
• pp.120-128
• /
• 2003

Fishes were caught by a set net in the coastal waters off Yosu, Korea from April to October, 2001, and seasonal variation of abundance and species composition were studied. Fifty two species were identified as fish $(89\%)\;cephalopods\;(10\%)\;and\;crustaeans\;(1\%).$ Of the fishes Engraulis japonicus, Trachurus japonicus and Trichiurus lepturus were dominant species representing $64.1\%$ in total number of individuals. The number of species was high in spring and low in summer; number of individuals was high in spring and low in autumn. The diversity index (H') was 0.4-0.7 The abundance and species composition fluctuated seasonally. Occurrence of the various stages of fishes indicated that Scombia japonicus, T. japonicus and E japonicus utilized in the area as spawning ground, Conger myriaster larvae, Ammodytes personatus and Seriola quinqueradiata as nursery ground, and T. lepturus and Ilisha elongata as spawning and nursery grounds.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.4
• /
• pp.467-479
• /
• 2021

The distribution and abundance of fish eggs and larvae were investigated from February to December 2020 along the coastal waters of Korea. The eggs and larvae were identified using the mitochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) and 16s rRNA gene. During the study period, eggs of overall 45 taxa belonging to 26 families were collected and larvae of overall 39 taxa belonging to 23 families were collected. In Yeongil Bay, eggs of Engraulis japonicus, which accounted for 83.9% of the total population, was the most dominant species, followed by Sardinops sagax (4.0%), Repomucenus valenciennei (3.8%) and E. japonicus larvae, which accounted for 34.9% of the total population. These were followed by Sebastiscus marmoratus (31.0%). In Gomso Bay, E. japonicus eggs accounted for 61.7% of the total population, followed by Sillago japonica (14.0%), Johnius grypotus (8.8%) and Pholis fangi larvae, which accounted for 53.5% of the total population, followed by Ammodytes personatus (34.1%). In Jinhae Bay, E. japonicus eggs accounted for 86.0% of the total population, followed by Leiognathus nuchalis (4.1%), Konosirus punctatus (3.7%) and E. japonicus larvae, which accounted for 48.7% of the total population, followed by Parablennius yatabei (21.6%).

• Korean Journal of Ichthyology
• /
• v.6 no.1
• /
• pp.60-70
• /
• 1994

To study the composition and distribution of the ichthyoplankton in Kwangyang Bay, they were sampled at eight stations from February to December 1990, Abundance was the highest in June, and the number of taxa was the highest in August. Engraulis japonicus, Leiognathus nuchalis, Konosirus punctatus and Argyrosomus argentatus were dominant among 6 taxa of pelagic eggs. Engraulis japonicus, Gobiidae, Korwsirus punctatus, Argyrosomus argentatus and Leiognathus nuchalis were dominant among 21 taxa of fish larvae. The number of taxa was smaller than the previous study. Abundance during winter was low due to the reduction of abundance of winter spawning species. Ammodytes personatus and Enendrias fangi.

• Korean Journal of Ichthyology
• /
• v.21 no.3
• /
• pp.191-199
• /
• 2009

Fisheries resources collected by set net in the Mizo fishing ground off Namhae Island were studied from March to December 2004 to determine species composition and catch variation. The water temperature of the fishing ground ranged $10.9{\sim}25.1^{\circ}C$ A total of 69,147.5 kg comprising 39 species was caught during the survey period. Most of the catch was fishes (33 species); others included cephalopods (5 species) and crustaceans (1 species). The dominant species were migratory, such as Trichiurus lepturus, Ammodytes personatus, Engraulis japonicus, and Scomberomorus niphonius, and accounted for 81.2% of the total catch. Sub-dominant species were Sardinops melanostictus, Acanthopagrus schlegeli, shrimps, and Todarodes pacificus, but they accounted for only 12.1% of the total. The catch by set net during the fishing period was much higher in spring and in autumn than in summer, relating to the recruitment of dominant species. Although the number of species had a tendency to decreased after summer, the catch in autumn was also higher than that in spring due to high temperatures (>$17^{\circ}C$ and seasonal variation of dominant species. The dominant species in spring were A. personatus and E. japonicus and in autumn were T. lepturus, S. niphonius, and E. japonicus.