• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.2
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• pp.118-127
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• 2011

This study was investigated seasonal variation and species composition of fish species at artificial reefs (octangle three-stage compartment type and dice type)and natural rock in the Shinyang-Ri coastal waters off Jeju Island with visual census method in January 2009, April 2009, July 2009, September 2009, December 2009, March 2010, June 2010, and September 2010. A total of 44 fish species was occurred, and the dominant fish species were Apogon semilineatus, Chromis notata, Trachurus japonicus, Sebastes thompsoni and Apogon doederleini. The number of individuals of fishes was higher at April 2009 and March 2010, however, lower at June 2010 and September 2010. The number of fish speices was higher at artificial reefs than those of at natural rock. Apogon semilineatus was dominant at octangle three-stage compartment type and the dice type artificial reefs, whereas Chromis notata was for natural rock. These results indicated that artificial reefs were good habitats for a variety of fish species in the Shinyang-Ri coastal waters off Jeju Island.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.3
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• pp.233-242
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• 2019

Species composition and yearly variation of fish eggs and larval fishes were investigated from 2014 to 2016. During the study period, the fish eggs were identified as belonging to 14 taxa. The dominant species of fish eggs were Leiognathus nuchalis, Engraulis japonicus, and Konosirus punctatus. These three species accounted for 97.4% of the total number of individuals collected. The collected larval fishes were identified into 37 taxa, 22 families, and seven orders. The dominant species of larval fish were Leiognathus nuchalis, and Gobiidae fishes. These three species accounted for 85.4% of the total number of individuals collected. The diversity index of the larval fishes was the highest in 2014 (H' = 1.60) and the lowest in 2015 (H' = 1.15). The evenness index was the highest in 2016 (J = 0.51) and the lowest in 2015 (J = 0.39). The dominance index was the highest in 2015 (D = 83.5%) and the lowest in 2016 (D = 70.9%). In addition, the economically important species in this area were Engraulis japonicus, Konosirus punctatus, Hippocampus coronatus, Sebastes schlegelii, Acanthopagrus schlegeli, and Cynoglossus joyneri.

• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.106-118
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• 2013

Monthly variation in species composition of shallow water fish in Cheonsu Bay were determined using samples collected by a beach seine in the shallow water at Namdang beach from April 2010 to March 2011. The species composition were compared to the data obtained in 1885~86 and in 1993, and factors affecting the long-term change in species composition were analyzed. Fish collected during the study were 25 species, 2,194 individuals and 16,762 g. Chelon haematocheilus were predominated in abundance, accounting 68.5% in the number of individuals. A few number of fish were collected during the cold months from November to April. Abundance was high from July to September by a large catch of juveniles of pelagic fish. Species composition in 1993 did not differ significantly from that in 1985~86 although Fabonigobius gymnauchen living in the fine sediments were increased in abundance. Abundance increase of this gobiid fish was considered to be related to the sedimentation of fine particles due to weakened water circulation after dike construction. The number of species and catch amount in 2010~11 were significantly decreased comparing to those of the former periods; especially in pelagic fish and benthic fish, but C. haematocheilus were greatly increased in abundance. C. haematocheilus is an estuarine fish being able to survive in relatively poor quality of water. This increase seems to be related to fish larvae from the culture net cages recently installed in the inner bay. Recent decrease in abundance of shallow water fish suggested that water quality has been gradually getting poor and recently attained over a critical level for the nursery function of fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.512-519
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• 1999

Seasonal variation in species composition and abundance of demersal fish in Yongil Bay were determined by analyzing samples collected using an otter trawl from January to October 1991. Of 59 species identified, Repomucenus lunatus, Tridentiger trigonocephalus, Repomucenus heguenini, Ammodytes personatus and Sillago japonica were dominated in abundance. Number of spiecies and biomass were low in winter and high in spring and summer. Species composition did not show spatial variation but showed seasonal variation. Number of spicies, abundance in number of individuals ($630 inds./10^3\;m^2$) and in biomass ($13,131g/10^3\;m^2$), and species diversity (2.00-2.54) of fish in Yongil Bay were higher than those of the coastal waters in the Yellow Sea or in the South Sea of Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.619-625
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• 2013

We investigated yearly fluctuation of the fish species composition of beam trawls off Maemuldo in the east southern sea of Korea, from March 2007 to November 2009. A total of 75 fish species were collected during the period. The number of fish species accumulated amounted to 54, 64 and 75 species in 2007, 2008 and 2009, respectively. The number of newly occurring species increased with time. The number of expected resident species in Maemuldo was estimated as 9 species including Conger myrister, Okamejei kenojei and Pholis nebulosa, each of which appeared more than 14 out of a total 27 times. Cluster analysis showed that the years 2007 and 2008 were closely clustered, while the year 2009 was distantly clustered with 2007 and 2008. This may be due to the high catch ratio of Clidoderma asperrimum in 2009 alone, when a low water temperature phenomenon was observed unlike the situation in 2007 and 2008.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.424-430
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• 2014

Two major temperature fronts, the Subpolar (Gosung, Gang-won-do; $38^{\circ}-41^{\circ}N$) and Thermal (Jukbyun, Gyeong-sang-buk-do; $36^{\circ}-37^{\circ}N$) fronts, are found in the East Sea along the east coast of Korea. These are located roughly where the Tsushima Warm Current and North Korea Cold Current intersect. To clarify the effect of the Thermal Front, we investigated seasonal variation in fish species composition using set nets in two areas located north (Jangho, Gang-won-do) and south (Hupo, Gyeong-sang-buk-do) of Jukbyun, Gyeong-sang-buk-do, and compared the sea water temperature and salinity. We collected a total of 38 fish species in Hupo and 25 in Jangho. Trachurus japonicus was the most common species at both sites, but the subdominant species differed. At Hupo, the subdominant species were Konosirus punctatus and Diodon holocanthus, whereas Clupea pallasii and Scomber japonicus were subdominant at Jangho. Based on Froese and Pauly (2014), subtropical fishes accounted for 55% of fish in Hupo but only for 33% in Jangho. The difference in fish species composition was most obvious in May and August. According to the Korea Hydrographic and Oceanographic Administration, sea surface temperature and salinity were slightly higher at Hupo than at Jangho. Our findings suggest that the oceanographic boundary resulting from the Thermal Front near Jukbyun, Gyeong-sang-bukdo may have a major effect on the distribution of migratory fish species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.353-362
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• 2008

The fish species composition and variation in the Youngil Bay, East Sea of Korea, were investigated every month from January, 2001, to December, 2002, using gill nets for sample collection. A total of 63 fish species belonging to 31 families under 10 orders, and a total of 40 species belonging to 26 families under 8 orders, were identified in 2001 and 2002, respectively. Of these, the families Pleuronectidae (9 species), Scorpaenidae (8 species) and Cottidae (5 species) were dominant in 2001, whereas Pleuronectidae (4 species), Cottidae (3 species) and Hexagrammidae (3 species) were dominant in 2002. The number of species recovered was the highest in August, 2001 (34 species) and January and September, 2002 (14 species each), and lowest in May, 2001 (6 species) and December, 2002 (5 species). The principal component analysis for each year showed that fish species composition differed over time even within the same sample area. In addition, the relationship between PC scores and temperature showed a positive relationship in 2001, but a negative relationship in 2002.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.883-888
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• 2016

We investigated fish species composition seasonally at the intake and discharge of Weolseong Nuclear Power Plant (WS-NPP) from February to November 2008 using a trammel net. At the intake, 121 individuals belonging to 28 species were collected, and 157 fish from 34 species were sampled at the WS-NPP discharge. Dominant species at the intake were Chelidonichthys spinosus (17.2%), Scomber japonicus (11.5%) and Ditrema temminckii (8.2%) at the intake, while Sillago japonica (18.5%), Chelidonichthys spinosus (13.4%) and Konosirus punctatus (8.3%) dominated at the discharge. The species count and diversity index at the discharge were highest during winter, whereas those at the intake were highest during spring, perhaps due to warm seawater at the discharge site. This study is the first to reveal an effect of effluent water on the aggregation of warm water fish species during winter.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.546-552
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• 2007

The objectives of this study were to analyze fish compositions, based on trophic guilds and tolerance guilds and determine community characteristics structure at five sampling sites of Yeongsan Lake during July 2006-May 2007. Total number of species sampled was 30 species and the number was 1350. Cyprinidae (77%) and Centrarchidae (15.7%) dominated the community and then followed by Cobitidae(2.7%), Gobiidae(2.4%), Mugilidae (0.5%), and others (0.1%). The relative abundance of tolerant and omnivore species at all sites was 63% and 77% of the total, respectively, suggesting an ecological degradations in the Lake. Exotics species such as large mouth bass (Micropterus salmoides), which is a top-carnivore in the water distributed at all sampling sites, implying that ecological disturbance was severe based on previous reference of US EPA (1991). Also, we found external anomalies such as external deformities, bleeding and tumors and not found migratory fish. Analysis of fish community structure showed that species diversity index and richness index was the highest in Site 1 and the dominance index was the highest in Site 2. In this study, high proportions of tolerant species and omnivore species, widespread exotic species, and frequent observations of abnormal fish. Such problems may be directly or indirectly associated with high nutrient enrichments and the reduced flow velocity by the dam construction. The ecosystem restoration by dam removal or removal of exotic top-carnivore fish may be one of the best strategies for better lak management.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.129-140
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• 2006

To find out the seasonal variation of species composition and distribution of fish eggs and larvae in the western part of Jeju Island, investigations were carried out with plankton net during five different months from September 2004 to August 2005. The mean abundance of fish eggs and larvae showed a maximum values in summer (August). During the survey period, total 59 species (51 genus, 26 families and 10 orders) of fish larvae were identified. Among the 10 orders, Perciformes (41 species, 15 families), Scorpaeniformes (7 species, 2 families) and Gasterosteiformes (2 species, 2 families) were the dominant species in this study area. The number of species was higher in high water temperature period than in low one, showing a peak in August as 25 species, and the lowest in May as 6 species. Engraulis japonicus, Scomber japonicus and Scombridae spp. which were migratory fish species occurred abundantly in summer. On the other hand, Sebastiscus marmoratus and Sebastes inermis which were sedentary fish species occurred abundantly in winter.