• Water for future
• /
• v.24 no.4
• /
• pp.22-24
• /
• 1991

• Korean Journal of Ichthyology
• /
• v.18 no.3
• /
• pp.184-192
• /
• 2006

To investigate reproductive cycle of Tridentiger obscurus in Jeju, total 408 fish were collected in brackish area (May 2004 to August 2005) and total 271 fish were collected in tidal pool (July 2004 to August 2005), respectively. Water temperature ranged $11.0{\sim}21.6^{\circ}C$ in brackish area. Water temperature of tidal pool ($11.1{\sim}24.5^{\circ}C$) in 2005 was similar to that of brackish area although it were highest $30.1{\sim}29.2^{\circ}C$ from July to August in 2004. In brackish area, female gonadosomatic index (GSI) increased in April and maintained high values from May to August. The reproductive cycle can be grouped into the following successive stages in the ovary: immature (November to May), maturing (March to September), ripe and spawning (May to September), and degenerating (July to December). In the tidal pool, female GSI rapidly increased in April and maintained high values until July in 2005. However, it has been low in July 2004 when water temperature was highest. The reproductive cycle can be grouped into the following successive stages in the ovary: immature (August to April), maturing (March to August), ripe and spawning (March to July), and degenerating (July to August 2004 and August 2005). Fecundity of mature female ranged from 1,214 to 12,109 in brackish and ranged from 2,427 to 13,892 in tidal pool area. The fecundity of fish in the tidal pool was significantly higher than that of fish in brackish area. Fecundity was correlated positively with total length and body weigh. Although the large group (> 111 mm total length) in brackish area observed only in spawning season, one in the tidal pool observed from October 2004 until next spawning season. Frequency of the large group was 0 to 12% and 11.4 to 57.9% in brackish area and tidal pool, respectively. These results were indicated that gonadal development of T. obscurus was affected to water temperature and day length.

• Korean Journal of Ichthyology
• /
• v.28 no.1
• /
• pp.47-51
• /
• 2016

Three specimens of Abudefduf septemfasciatus were collected firstly from tidal pools on the southern and northern coasts of Jeju Island, Korea in August 2015. This species is characterized by black blotches on the upper origin of the pectoral fin, upper caudal peduncle and a dorsal fin between the second and fourth spines, predorsal scales beyond to above the middle of the eye, 12~13 soft dorsal and anal fin rays, and 20 lateral-line scales. This species is distinguishable from Abudefduf sordidus by soft dorsal and anal fin rays, location of caudal peduncle blotch, and location of the dorsal fin blotch. The newly proposed Korean name is "Il-gop-jul-ja-dom".

• Korean Journal of Ichthyology
• /
• v.20 no.1
• /
• pp.54-60
• /
• 2008

This study was conducted to investigate the species composition and distribution patterns of intertidal fishes from the Shandong Peninsula, China from August 2006 to September 2007. The collected fishes were composed of 28 species, belonging to 21 genera, 14 families and 6 orders. Among them, the family Gobiidae was most abundant in both the number of species and individuals, while two species including Hexagrammos agrammus and Sebastes schlegelii were caught in large quantities of young fishes. In this study, Sebastes koreanus and Porocottus leptosomus known as Korean endemic species so far were collected in the Shandong Peninsula, therefore it should be revised that these two species were distributed on the North Yellow Sea and owned by both China and Korea.

• Journal of Korea Society of Industrial Information Systems
• /
• v.27 no.6
• /
• pp.105-114
• /
• 2022

We examine berth allocation problems in tidal bulk ports with an objective of minimizing the demurrage and dispatch associated berthing cost. In the proposed optimization model inventory (or stock) level constraints are considered so as to satisfy the service level requirements in bulk terminals. It is shown that the mathematical programming formulation of this research provides improved schedule resolution and solution accuracy. We also show that the conventional big-M method of standard resource allocation models can be exempted in tidal bulk ports, and thus the computational efficiency can be significantly improved.

• Korean Journal of Ichthyology
• /
• v.17 no.2
• /
• pp.142-147
• /
• 2005

To research changes in the fish community of intertidal zones in relation to the construction of the Saemangeum tidal embankment, fishes were collected in the tide pools of Naechodo, Gunsan-si, and of Haechang, Buan-gun in Jeollabuk-do, every month from December 2002 to October 2004. Based on the fishes collected and data from previous studies show that in the tide pools of Haechang, the number of species decreased, and the dominant species is Tridentiger trigonocephalus, as before. However, in the tide pools of Naechodo, the number of species decreased, and the dominant species changed from T. trigonocephalus to Synechogobius hasta. Favonigobius gymnauchen, which inhabits sand-beds, decreased remarkably. Meanwhile, in the intertidal zone of Haechang, young black porgy were caught in large quantities, while in the intertidal zone of Naechodo, young Acanthopagrus schlegelii and Lateolabrax japonicus, which had been caught in a large amounts between 1994 and 2000, were not caught. The results are thought to show that the intertidal zone of Naechodo, Gunsan-si, had more deposits by tide flats than that of Haechang, Buan-gun, which drastically changed the habitat of its fish community.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.35 no.2
• /
• pp.117-121
• /
• 1990

A sweet corn hybrid, Golden Cross Bantam 70, was grown at 5 plant populations (5,000, 6,000, 7,000, 8,000, and 9,000 plants/10a) under the transparent P .E. film mulch to find the best yield evaluation method. Plant population did not affect early plant growth, culm length, ear height, and silking date. However, number of tillers at harvest decreased but leaf area index increased with increased plant population. Marketable ears were divided into two classes; the first grade of which husked ear weight over l50g (unhusked ear weight 230g) and the second grade of which husked ear weight between 100 and 150g (unhusked ear weight between 180 and 230g) according to the whole sale market price. Average length, thickness, and weight of marketable ears over 100g of husked ears decreased with increased plant population. The proportion of ears over 150g decreased with increased plant population. However, total number and weight of marketable ears and gross income per 10a calculated considering weight and number of ears increased with plant population. There were highly positive correlations between gross income and ear number or ear weight per unit area. At high plant populations the number of marketable ears was overestimated but ear weight underestimated compared with gross income. Dry matter yield of stover increased with increased plant population and ranged 755-944kg/10a with 20.7-24.5% dry matter content. Rice black-streaked dwarf virus infection rate was 10.6-14.9%, but it was not related to plant population.

• Korean Journal of Ichthyology
• /
• v.36 no.3
• /
• pp.273-281
• /
• 2024

In June and July 2023, a total of 101 Thryssa kammalensis larvae and juveniles were collected during an ichthyoplankton survey using RN80 in the waters around the southwest coasts of Korea. When pre-flexion larval stage (3.77~10.20 mm NL, n=22), some individuals have pterygiophores of dorsal and anal fins, but no apparent fin rays were formed. Line-shaped melanophores were distributed in a row from below the opercle to the anal fin base. When flexion larval stage (12.13~16.69 mm SL, n=14), the number of dorsal and anal fin rays were 13~15 and 18~23. Dot and line-shaped melanophores were distributed in a row in the ventral portion of the abdominal cavity, and melanophores appeared on the caudal fin. When post-flexion larval stage (17.23~21.73 mm SL, n=20), all fin rays appeared, and the number of pectoral, pelvic, anal and dorsal fin rays were 7~9, 4~5, 29~31 and 14~15, respectively. Dot and line-shaped melanophores were distributed in a row from the posterior of the preopercle to the ventral portion of the abdominal cavity, oval-shaped melanophores were distributed along the anal fin base, and melanophores concentrated lower lobe of the caudal fin. When juvenile stage (18.43~25.98 mm SL, n=45), the number of pectoral, pelvic, anal and dorsal fin rays were completed as 12~15, 7~8, 30~33 and 14~15, respectively. Point-shaped melanophores of the ventral position of the abdominal cavity disappeared, it continued in a row along the anal fin base to the lower caudal peduncle. Our results suggest that Thryssa kammalensis may use the sea around Chilsan-do Island as spawning and/or nursery ground between June and July.

• 월간산업보건
• /
• s.24
• /
• pp.4-10
• /
• 1990

• 월간산업보건
• /
• s.40
• /
• pp.11-13
• /
• 1991