• Fisheries and Aquatic Sciences
• /
• 제14권1호
• /
• pp.55-61
• /
• 2011

Fish larvae were collected monthly with an ichthyoplankton net from 18 stations (including four stations located in eelgrass beds) in Gamak Bay and Yeoja Bay, southern Korea, in 2007. In total, 33 species of fish larvae were collected, of which Engraulis japonicus (48.5%), Tridentiger trigonocephalus (21.5%), and Omobranchus elegans (9.2%) were dominant. Dominant species varied seasonally: Hexagrammos otakii during December and January, Pholis nebulosa during January and March, Acanthogobius flavimanus in April, T. trigonocephalus in May, E. japonicus during June, July, September, and November, and Sillago japonica in August. Dominant species also differed between sites inside and outside the bays. Leiognathus nuchalis, O. elegans, and T. trigonocephalus were more abundant inside, while H. otakii was more abundant outside. From cluster analysis, three groups were identified according to sampling months (January-April, May-September, and October-December) and two groups according to station (inside and outside bays). The occurrence of small larvae of almost all major fish species indicated that the bays were used as spawning and nursery grounds. An exception was Lateolabrax japonicus, whose specimens were relatively large (>19 mm TL), suggesting that this fish may spawn offshore, with its juveniles approaching the bays with growth.

• 한국농공학회논문집
• /
• 제52권3호
• /
• pp.1-7
• /
• 2010

The ichthyofauna and passing efficiency of fishways were surveyed in Geumgang estuary from May to October in 2009. The fishes collected were classified into 24 species, 23 genera belonging to 8 families. These 24 species consist of 17 freshwater fish species, 3 migration fish species and 4 peripheral freshwater fish species. Seasonal function of fishways showed the migration from May to June and returning to the reservoir of fishes be washed out to sea when sluice gate open by rainfall in July and August. Most of the fishes catched in fishways moved from middle tide to high tide except for July. Fishes ascended fishways between the middle ebb tide and the ebb tide only July, because small freshwater swim against the fishway for leaching the reservoir through the newly formed flow when the water level at the fishway kept dropping. Small fishes that body length less than 200 mm mainly used gabion type fishways and fishes over 200 mm utilized a cascade type fishways. Based on the total individuals collected, the efficiency of the fishway was 1 % for the anadromous fish and over 80 % for freshwater fish. Therefore, it is concluded that ecological function of the fishway in the Geumgang estuary dike be very important not only for fish migration but also freshwater fishes's returning.

• 한국농공학회:학술대회논문집
• /
• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
• /
• pp.721-726
• /
• 1999

The fishways on Namdae-cheon and Osib-cheon and the use of migratory fishes were investifated from July 1998 through Jung 1999. There are three types of fishways on these rivers. Those are baffled fishways, fish ladder, and fish ladder with gabion. Namdae-cheon has 7 baffled fishways and 19 fish ladder, and Osib-cheon has only fish ladder with gaboin. On Namdae-cheon 1,195 fishes of 24 species were collected. Amog these fishes 241 fishes of 9 species were anadromous fishes occupying 38% in species and 19% in number. On Osib-cheon 1,015 fishes of 24 species were collected. Among these fishes 240 fishes of 5 species were anadromous fishes occupying 21% in species and 24% in number. On Namdae-cheon the species number and auundance decreased gradually upstream. The poor structure of fishways seems to have worked as an obstacle to the upstream migration of fishes on Namdae-cheon. On Osib-cheon all the observed fish species except three -spined stickleback(Gasterosteus aculeatus aculeatus) which stay and spawn around downstream of river could migrate upstream. The good structure of fishways on this river is thought to have helped upstream fish migration.

• 한국수산과학회지
• /
• 제54권4호
• /
• pp.498-507
• /
• 2021

Ichthyoplankton (fish eggs and larvae) were collected seasonally collected from 2017 to 2019 to clarify whether Dokdo serves as a fish spawning and/or nursery ground. Fish eggs were identified and classified into 16 species. The dominant fish egg species were Engraulis japonicus, Maurolicus japonicus, and Parajulis poecilepterus. Fish larvae were identified and classified into 15 species. The dominant fish larvae species were E. japonicus, M. japonicus, and Sebastes owstoni. A cluster analysis similarity percentages revealed two distinct groupings according to sample location (stations) with E. japonicus and M. japonicus as the main group influencers. E. japonicus was the dominant species off Dokdo. The species diversity and abundance peaked in summer. The diversity index, richness index, and evenness index fluctuated seasonally. There were no predominant species variations among the years. Sedentary species such as P. poecilepterus, Semicossyphus reticulatus, and Glyptocephalus stelleri occurred in the inshore stations. E. japonicus, M. japonicus, and Trachipterus trachypterus occurred in the offshore stations. Our results show these species use Dokdo as spawning and nursery grounds.

• 한국물환경학회지
• /
• 제25권6호
• /
• pp.951-963
• /
• 2009

The community structure and ecological characteristics of fish community in Lake Paldang were investigated from May to September 2008. During the survey period, 53 species belonging to 13 families were collected. Dominant species was Squalidus japonicus coreanus representing 81.8% of total number and 25.7% of total biomass of collected fish and subdominant species was Lepomis macrochirus representing 3.3% of total number and 18.9% of total biomass of collected fish. There were 20 Korean endemic species (38% of collected species number) including Cottus koreanus and 4 exotic species (7.5%) including Micropterus salmoides. The similarity analysis of fish communities among water areas of Lake Paldang using UPGMA showed that fish community of North-Han River was similar to that of South-Han River area and was different from that of Gyeongan River area. Long-term variation of fish community from 1972 to present study in Lake Paldang showed decrease of the species numbers after dam construction until 1994, and gradual increase from 1996 to present study indicating the disturbance of lentic system by dam construction in the 1980s. The increase of species number in the late 2000s may results in part from the increase of survey sites of successive studies. L. macrochirus which was designated as a domestic ecosystem-disturbing alien species with wide food niche have shown more than 20% of relative abundance since 1996 indicating the adverse effect on not only fish community but also aquatic ecosystem food web of Lake Paldang.

• 한국수산과학회지
• /
• 제43권6호
• /
• pp.693-704
• /
• 2010

Seasonal variation in species composition around Dokdo, East Sea of Korea, was investigated using trammel-net catches, from 2006 to 2009. A total of 53 fish species belonging to 23 families in 12 orders were captured; the orders Perciformes (12 families, 22 species) and Scorpaeniformes (four families, 22 species) were dominant. Between 2008 and 2009, 43 species were collected by trammel net. The number of species was highest in August 2009 (25 species) and lowest in February 2009 (11 species). The number of individuals and total biomass peaked in November 2009. Diversity indices for fish catches were highest in August 2008 (2.4368) and lowest in November 2009 (0.4253). The dominant species were Thamnaconus modestus and Sebastes schlegeli. Hierarchical clustering analysis showed five fish groups, with frequency and number of individuals similar to results of correspondence analysis (CA), which showed a closer relationship to the year term than the season term. CA showed that temperature was an important factor influencing fish species richness and abundance. Three main fish assemblage types coexisted around Dokdo: an East Sea coastal fish assemblage, a subtropical fish assemblage, and a cold water fish assemblage.

• 한국어류학회지
• /
• 제10권1호
• /
• pp.11-23
• /
• 1998

1989년 5월부터 1990년 4월까지 매월 남해도 연안해역에서 소형 otter trawl을 이용하여 어류를 채집하여 종조성 및 계절 변동을 분석하였다. 조사기간 동안 총 64종의 어류가 채집되었다. 줄망둑(Acentrogobius pflaumii), 도화망둑(Chaeturichthys hexanema), 수염문절(Chaeturichthys sciistius), 청멸(Thryssa kammalensis), 실양태(Repomucenus valenciennei)가 많이 채집되었는데, 이들은 전체 개체수의 66.5%, 그리고 생체량의 34.9%를 차지하였다. 그 다음으로 주둥치(Leiognathus nuchalis), 붕장어(Conger myriaster), 병어(Pampus echinogaster), 참서대(Cynoglossus joyneri), 민태(Johnius grypotus), 칠서대(Cynoglossus interruptus), 열동가리돔(Apogon lineatus), 보구치(Argyrosomus argentatus), 밴댕이(Sardinella zunasi) 순으로 채집되었다. 본 조사해역에서 채집된 어류는 대부분이 체장 10cm 이하의 소형 어종이거나 대형 어종의 유어들로 구성되어 있었다. 남해도 연안해역의 어류 군집은 뚜렷한 계절 변동을 보였는데, 채집 어종수는 10 ~1월사이에 많았으며, 2~3월에 적었다. 채집 개체수 및 생체량은 4월과 9월에 높은 값을 보였으며, 수온이 낮은 2~3월에는 채집 어종수, 개체수 및 생체량 모두 낮은 값을 보였다.

• Journal of Nutrition and Health
• /
• 제29권2호
• /
• pp.188-191
• /
• 1996

This study was undertaken to determine the effects of fish oil supplementation with low dose on the lipid content and fatty acid composition of breast milk. Among 18 lactating women who were exclusively breast-fed their babies, 6 were in control group and 12 were in fish lil groups. The subjects in fish oil groups were supplemented with 1.96g/d or 3.92g/d of fish oil for 2 weeks from 10 to 12 weeks of postpartum. All subjects consumed their usual diet at home. Breast milk samples were collected at the final day of experiment. By fish oil supplementation, the concentrations of triglyceride, cholesterol, free fatty acid and phospholipid as well as total lipid in breast milk tended to increase, but not significant. There was no dose-dependent response. The fatty acid composition of breast milk was not changed by fish oil supplementation. These results suggest that low dose of fish oil supplementation may increase of lipid content, but does not affect on the fatty acid composition of breast milk.

• 한국수산과학회지
• /
• 제50권4호
• /
• pp.429-436
• /
• 2017

The seasonal and interannual variations in fish assemblages in the coastal waters off Gijang were examined with an otter trawl from 2015 to 2016. A total of 59 fish species was collected during the study period. The dominant species were Caelorinchus multispinulosus, Clupea pallasii pallasii and Chelidonichthys spinosus. Seasonal changes in fish assemblages appeared to be distinct in the study area. The fish assemblages in summer and autumn were clearly distinguishable from those in other seasons, and the largest numbers of species and individuals were captured in winter and summer, respectively. Because fish assemblages are closely related to changes in water temperature, long-term changes in water temperature can have a significant impact on the productivity of offshore fisheries by changing fish species composition, habitat migration, and growth rate of fish.

• Fisheries and Aquatic Sciences
• /
• 제26권3호
• /
• pp.224-233
• /
• 2023

This research was conducted at Langgur City, Southeast Maluku Regency, Maluku Province, Eastern Indonesia from November 2020 to February 2021 to study biological aspects of roundscads (Decapterus spp.) which consist of species composition, sex ratio, gonad maturation level, size distribution, length-weight relationship and condition factor. Samples were collected at traditional fish market in Langgur City. Fish samples collected at the market were put into cool box and then brought to the laboratory for further examination. Fish samples were identified, separated based on species, dissected to determine their sex and gonad maturation stage and then measured. Totally, there were 290 specimen collected which consist of five species namely Decapterus kurroides, D. macarellus, D. macrosoma, D. muroadsi and D. russelli. Sex ratio between male and female for all species showed 1:1. Gonad maturation level showed that stage I and II have higher percentage than stage III and IV indicates immature fish more dominant compare to mature one. Among five species found, D. macarellus has larger size while the smaller belongs to D. muroadsi. Results of length-weight relationship analysis showed that roundscads inhabiting Southeast Maluku waters have isometric and negative allometric growth pattern with relative condition factor around 1.00.