• Korean Journal of Ichthyology
• /
• v.24 no.1
• /
• pp.27-34
• /
• 2012

Population ecology of $Acheilognathus$ $macropterus$ was investigated at the part of the Bulgapcheon stream in Korea from March to November in 2006 and April in 2008. It mainly inhabited in slow water with sand and mud bottoms. The standard length of this population indicated that below 48 mm group is one year old, 48~58mm group is two years old, 58~64mm group is three years old and longer than 66 mm group is regarded over four years old. The sex ratio of the female to the male was 1:0.99. Spawning season from April to June with the water temperature in $15{\sim}20^{\circ}C$. The average number of eggs in ovary was $680{\pm}209$. The matured egg size was $1.92{\times}1.60mm$. Stomach contents were mainly phytoplanktons such as the genera Navicular, Cymbella, Fragilaria.

• Korean Journal of Ichthyology
• /
• v.28 no.1
• /
• pp.28-34
• /
• 2016

The anatomy and histology of the olfactory organ in Favonigobius gymnauchen was investigated using a stereo microscopy, light microscopy and scanning electron microscopy. The paired olfactory organs in the dorsal snout are set in between the upper lip and the eyes. These organs are composed of two openings (anterior nostril with a tubular structure and posterior nostril), a single olfactory cavity, two nasal sac (ethmoidal and lacrimal sacs), olfactory nerve and olfactory bulb. The distributional pattern of the sensory epithelium is a only one type (continuous type). This epithelium is made up of the receptor cell, supporting cell and basal cell. The receptor cell has a only one type (ciliated receptor cell with 3~4 cilia). The non-sensory epithelium is built of the stratified epithelial cells and has mucous openings on the surface. Such an olfactory organ in F. gymnauchen may be considered to reflect its ecological habitat as a shallow water or tidal pool in the coastal zone.

• Korean Journal of Ichthyology
• /
• v.28 no.2
• /
• pp.72-78
• /
• 2016

The age and spawning characteristics of Iksookimia pacifica were investigated in this study to provide baseline data for its ecological characteristics in the Bukcheon (stream), Goseong-gun, Gangwon-do, Korea from January to December, 2013. Age groups of I. pacifica (female) estimated by the frequency distribution of total length in the spawning season indicated that the 30~49 mm group is 1 year old, the 50~74 mm group is 2 years old, the 75~99 mm group is 3 years old, the 100~124 mm group is 4 years old, and the 130~160 mm group is $5{\leq}$years old. The sex ratio (♂/♀) was 0.63, and females were 30~60 mm larger than males. The lamina circularis at the base of pectoral fins in males as a secondary sexual character was created at the 13th month after hatching. The spawning season according to the gonadosomatic index (GSI) was July to August (main spawning season in July) with water temperatures of $20{\sim}25^{\circ}C$. The average number of eggs was $2,503{\pm}1,337$ with a diameter of $1.11{\pm}0.04mm$ in mature eggs.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.6
• /
• pp.945-959
• /
• 2014

This study was conducted to provide basic data for optimal fisheries management through the accurate understanding the catches, fishing level, species composition, distribution characteristics and fisheries status of trammel net in Gangwon Province. As the results of trammel net survey, Pisces were collected 77 species, 1,983.0 kg, Crustacea 9 species, 569.0 kg, Cephalopoda 5 species, 75.3 kg, Gastropoda 12 species, 16.5 kg in the coastal waters of Sokcho and Pisces 55 species, 3,681.5 kg, Crustacea 6 species, 2,229.8 kg, Gastropoda 10 species, 72.8 kg, Cephalopoda 4 species, 10.1 kg in the coastal waters of Donghae, respectively. The catches of important species with season and depths showed that the main target species is Pleuronectidae spp. at all depth and Aptocyclus ventricosus at <100 m in Sokcho, Liparis spp. and Dasycottus setiger at 200-500 m in Donghae, respectively. The mean total length (cm) of Gadus macrocephalus and Aptocyclus ventricosus didn't appear significant difference, but the mean total length of Pleuronectidae spp., Liparis spp. and D. setiger in Donghae is bigger than in Sokcho. From the cluster and MDS analysis based on Bray-Curtis similarity matrix of fourth root transformed, catches data of dominant species in the coastal waters of Sokcho and Donghae was divided into three different groups of the demersal organisms community in 12 survey of Donghae (Group A) and Jul., Oct.-Dec. survey of Sokcho (Group B) and Jan.-Jun. and Aug.-Sep. survey of Sokcho (Group C).

• Korean Journal of Ichthyology
• /
• v.32 no.3
• /
• pp.182-190
• /
• 2020

The endangered Pseudopungtungia tenuicorpa were reintroduced to the Jojongcheon Stream in the Hangang River 2011~2012 as part of the restoration project. Since then, the restoration project has been evaluated as a failure because the P. tenuicorpa were not collected from the discharge site 2014~2016. This study was conducted 2017~2019 to verify that the P. tenuicorpa restoration project failed. Six locations were selected, including the discharge site, and the fish collection method used skimming nets, cast nets, long bag set nets, and scuba diving. In the survey results, 13 individuals were collected in a 0.5 km section, including the discharge station. The P. tenuicorpa habitat was approximately at a water depth of 0.5 m to 2 m in run water flow with the boulders and rocks. The age of the collected P. tenuicorpa were 0+ to 3-years-old, and the generation alternation was occurring stably. Thus, the P. tenuicorpa restoration project was evaluated as partially-successful, as the P. tenuicorpa, re-introduced to the Jojongcheon Stream, settled in its habitat with stable generation alternation.

• Korean Journal of Ichthyology
• /
• v.32 no.3
• /
• pp.143-147
• /
• 2020

The feeding habits of ocellate spot skate (Okamejei kenojei) were studied by analysis of stomach contents. Specimens of O. kenojei (n=379) were collected in the cosatal waters five west Islands of the Korea, monthly from January to December 2019. The size of O. kenojei ranged from 5.9 to 34.5 cm in disc width (DW). O. kenojei was consumed mainly macrura (77.9%) and pisces (21.9%) in % IRI. But, brachyura, stomatopoda, cephalopods, and others showed a low ratio. The macruara feeding rate was highest in summer, whereas the proportion of pisces was the higher in winter than other seasons.

• Korean Journal of Ichthyology
• /
• v.30 no.2
• /
• pp.71-74
• /
• 2018

The karyotype analysis of an endangered freshwater fish, Microphysogobio koreensis, was performed to obtain basic data for phylogenetic information. To carry out our study, 4 specimens were collected in Seomjingang River and Nakdongang River and its kidney was treated by flame-drying method. The chromosome number of this species demonstrated 50 diploid chromosomes, with two populations of M. koreensis not significantly different. The karyotype revealed 2n=26m+24sm, consisting of 26 metacentric (m) and 24 submetacentric (sm) chromosomes with the total fundamental arm number determined as FN=100. Total arm length and arm ratio of the chromosomes were $1.44{\sim}2.68{\mu}m$ and 1.27~2.27, respectively. The karyotype of M. koreensis was first reported in this study.

• Korean Journal of Ichthyology
• /
• v.30 no.2
• /
• pp.92-99
• /
• 2018

Feeding ecology of endangered Korean endemic miho spine loach, Cobitis choii, was investigated in Jicheon Stream, Geumgang River, Korea to provide ecological characteristics and baseline data for its restoration. C. choii is active during daylight hours above sand from March to October when the water temperature exceeded $13^{\circ}C$, but tended hibernate in the stream bottoms (sand) in the winter months (November~February) when the water temperature was lower than $13^{\circ}C$. They fed (index of relative importance, IRI) mainly Diptera (69.9%), Copepoda (23.2%), Arcellidae (2.3%), Branchiopoda (2.0%) and Ploima (2.0%). And their small juvenile (age 0+) fed mainly small size, Ploima and Branchiopoda, however, they ate mainly large size, Chilonomidae, while growing to adult fish (age 2+~3+).

• Korean Journal of Ichthyology
• /
• v.31 no.4
• /
• pp.208-213
• /
• 2019

Spermatozoa of Aphyocypris chinensis was studied by transmission electron microscopy. The investiation revaled that, spermatozoa display a round head, a small midpiece and a long tail region. In the spermatozoa, the nucleus contains highly condensed homogeneous chromation with small electron lucent areas. The base of the nucleus is slightly invaginated laterally by the nuclear fossa which contains the proximal centriole. The two centrioles orientated at an obtus angle (130°) to each other. The midpiece encircles the flagellum and is completely separated from it by the cytoplasmic channel. The midpiece contains more than 12 mitochondria. The mitochondria are arranged in 4~5 layer and are asymmetrically distributed in the postnuclear cytoplasm. The mitochondria surround the proximal part of the flagellum. The flagellum has classical 9+2 axoneme and no lateral fins. The spermatozoa of A. chinensis are similar to those of other cyprinids having a spherical head with a shallow nuclear fossa, a short midpiece including the asymmetrical arrangement of mitochondria and the lateral insertion of flagellum. However, there are some differences in the orientation of centrioles and the number of the mitochondria.

• The Korean Journal of Zoology
• /
• v.34 no.4
• /
• pp.433-451
• /
• 1991

척추동물(7목 23종)의 췌장에서 insulin( B)세포, glucagon(A)세포, somatostatin( D)세포 및 pancreatic polypeptide( PP)세포 등을 면역세포화학법으로 동정하여 이들의 출현율, 분포양상 및 형태 등을 계통별로 비교하였다. 파충강의 거북목, 양서강의 유미목 및 어강의 악상대목 들을 제외한 모든 종에서 췌도의 형성을 관찰할 수 있었으며, 췌도를 구성하는 내분비세포의 크기에는 계통간의 차이가 있었다. B세포는 파충강의 것이 가장 크고, 양서강, 어강의 순이 었으며 A와 PP세포는 양서강, 파충강 및 어강의 순서였다. D세포는 양서강의 것이 가장 윤고, 다음이 어장이었으며, 파충강의 것이 가장 작았다. 이들 세포의 모양은 B세포의 경우 양서강과 어장에서는 원형, 난원형 및 방추형이었으며, 파충강에서는 원추형 및 단기형 등 다양한 모습이었다. A세포는 어강에서는 원헝, 난원형 및 방추형이 고르게 나타났고, 파충강과 양서 강에서는 원주형, 다각형 및 쐐기형이 나타났다. D세포는 모든 동물에서 원형, 난원형 및 방추형이 관찰되었고, 특히 파충강에서는 원추형및 쐐기형도 나타났다. PP세포는 주로 방추형 및 반원형이 대다수이였으며 간혹 원형 또는 다각형 등의 모습도 나타났다. 각 내분비세포의 출현율은 파충강 열 어강 들에서는 B, A, D 및 PP세포 순이었으나, 양서 강에서는 B, A, PP 및 D세포 순으로 나타났다. B와 PP세포는 양서강, 어강 및 파충강 순서로 출현하였고, A세포는 파충강, 어강 및 양서강의 순서이었으며 D세포는 어강, 파충강 및 양서강의 순서였다. 췌도 내에서의 세포의 분포 위치는 세포의 종류에 따라 차이를 보여 B세포의 경우 대다수 동물들에서 중앙부에 균등하게 분포하였으나 A, D및 PP세포는 주로 췌도 주변부에 분포하였고, 어강에서의 D세포는 췌도 중앙부에서도 관찰되었다. 일반적으로 파충강 및 양서 강에서는 외분비 선포조직에서초 내분비세포들이 출현하였으나, 어강에서는 내분비세포가 전혀 출현하지 않았다. 양서강 및 어강 들의 일부 수에서는 췌관상피에서도 드물게 나타났다.