Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity (AL50), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

Changes in ecosystem risks were evaluated using the ecosystem-based fisheries assessment (EBFA) approach of Zhang et al. (2009, 2010) and the comprehensive ecosystem-based fisheries management (EBFM) plan was made for the southern sea of Korea in this study. The risk assessment of the southern sea ecosystem was conducted by establishing ecosystem management objectives and by estimating risk scores (RS) for indicators. To conduct this analysis a number of indicators and their reference points for assessing these risk scores were developed in this study. The number of indicators in the risk analysis was 28 for the quantitative tier 1 analysis and 30 for the qualitative tier 2 analysis. The objective risk index (ORI), species risk index (SRI) and fisheries risk index (FRI) were calculated from the risk scores. Comparing the past (1988) and the current (2008) status of fisheries resources, management implications were discussed. The fishery risk index (FRI) of large purse seine fishery in the southern sea of Korea decreased substantially from 0.972 in 1988 to 0.883 in 2008, and improvement in the management of fisheries operated in the southern sea of Korea.

Species composition of fishes and the recruitment properties of jack mackerel, Trachurus japonicus, in the waters around the Geumo Islands in the mid-South Sea were investigated by using both sides fyke nets every month from February to December 2010. During study period, a total of 30,503 fishes (1,380.4 kg) were collected and classified into 2 classes, 16 orders, 61 families and 121 species. The dominant species was jack mackerel occupying 80.5% of total individuals and 44.4% of total biomass. The fork length range of jack mackerel was 5.5-26.8 cm and individuals about 6 cm was appeared only in the middle and southern area of the Geumo Islands in May. The new recruitment of jack mackerel appeared from May in the waters around the Geumo Islands is probably caused by the warm water intrusion associated with the development of stratification due to the extinction of seasonal coastal cold waters by the increase of solar radiation heat. Furthermore, the jack mackerels less than 6 cm recruiting in the mid-South Sea in spring were considered as mixed ones by individuals spawned in the East China Sea and in the waters around the Jeju Island considering the collected time, migration period and spawning time of them.

Maturation and spawning of the Shotted halibut, Eopsetta grigorjewi was investigated based on the samples captured in South Korean waters from January 2008 to December 2009. Gonadosomatic index began to increase in December, and reached maximum between January to March. After spawning it began to decrease from May. Reproductive season was estimated to January-April, with peak in February. Fecundity was proportional to the size of the female, with the clutch size varying from 170,000 eggs in the smallest female (total length, 28.9cm) to 1,300,000 eggs in the largest (total length, 41.5cm). Size at 50% sexual maturity (TL50), determined from mature females, was 28.8cm. Annual reproductive cycles of this species could be divided into six successive stages; immature stage (May-October), nucleolus stage (November-January), yolk vesicle stage (January-February), vitellogenic and ripe stage (January-April) and spent stage (April-May).

Maturation and spawning of the Blackthroat seaperch, Doderleinia berycoides were investigated based on the samples captured in Korean waters from January 2008 to December 2009. Gonadosomatic index began to increase in June, and reached maximum between July to September. After spawning it began to decrease from October. Reproductive season was estimated to July-September, with peak in August. Fecundity was proportional to the size of the female, with the clutch size varying from 115,500 eggs in the smallest female (TL〓28.2cm) to 652,000 eggs in the largest (TL〓33.5cm). Size at 50% sexual maturity (TL50), determined from mature females, was 29.6cm. Annual reproductive cycles of this species could be divided into six successive stages; immature stage (October-May), nucleolus stage (June-July), yolk vesicle stage (July-August), vitellogenic stage (June-September), ripe and spent stage (August-October).

Characteristics of age and growth of the black rockfish, Sebastes inermis sampled in the Jeonnam Marine Ranching Area (JMRA) around Geumo Islands south of Yeosu were investigated using 642 otoliths from March 2009 to February 2010. The opaque zone was formed in September once a year and hence it was used as an annulus. The parturient period was December to January, and therefore the duration from fertilization to the complete formation of the opaque zone was nineteen months. From the parameters calculated using the average length when the year ring was formed, growth of S. inermis were expressed by von Bertalanffy growth equation as Lt=23.267 (1-e-0.4406(t+1.1971)) for females and Lt=22.030 (1-e-0.5312(t+0.6834)) for males when is total length in age t. Through the growth equations, the maximum length was determined as 23.27cm for females and 22.03cm for males and the growth factor as 0.4406/yr and 0.5312/yr, respectively. Finally, the growth of female S. inermis is larger than the one of male S. inermis.

Species composition and seasonal variation of fish assemblage in Sacheon marine ranching, Korea were examined. Sampling was seasonally made by a shrimp trawl from February 2009 to November 2009. A total of 55 species were collected. Of these, five species was dominant species comprising 51.1% of the total number of individuals. Nine species represented 57.3% of the total biomass. While total abundance (number of individuals) was high in spring, total biomass and species richness (number of species) and diversity were high in autumn. Cluster analysis, based on seasonally abundance data of the 21 most common species, showed that the species were separated into 4 different groups. Group A composed of Pholis nebulosa, Pleuronectes yokohamae, Hypodytes rubripinnis, Hexagrammos otakii, Tridentiger trigonocephalus and Paracercis sexfasciata, which were year round residents, group B Congr myriaster, Leiognathus nuchalis, and Platycephalus indicus, which were abundant in autumn, group C Sillago japonica, Pseudaesopia japonica, Zoarces gilli, Pholis fangi, and Pleuronichthys cornutus which were abundant in spring, and group D Sillago sihama, Cociella sp., Johnius grypotus, Cynoglossus joyneri, Cynoglossus robustus, and Pennahia argentata, which were abundant in summer. Principal component analysis revealed that seasonal variation in the fish assemblage was attributed to the abundance of temporal species such as conger and sand smelt fishes, which were abundant in summer, due to seasonal variation of water temperature.

This study monitored a variety of marine fish communities in artificial reefs unit of the total 5 types (Dice type, Octagonal turtle type, Two-stage tube type, Gazebo type, Tetrapod type) which are located in the marine ranching at Jeju island by scuba diving in May, July, October and December 2009. Underwater photographing was accomplished at total 3 phases (condition of artificial reefs photographing, concentric circle movement photographing and line transect photographing). The preservation condition of artificial reefs facility was very good, and the dominant species were Chromis notatus, Sebastes thompsoni, Oplegnathus fasciatus and Halichoeres poecilopterus. Fish abundance was high in May and June, and low in October and December, 2009. Chromis notatus was dominant at the all types of artificial reefs, Halichoeres poecilopterus for Gazebo type and Tetrapod type of artificial reefs, and Sebastes thompsoni for Dice type, Octagonal turtle type and Two-stage tube type of artificial reefs.

To investigate seasonal variation of fisheries resources composition and their correlationships with environmental factors in the coastal ecosystem of the middle Yellow Sea of Korea, shrimp beam trawl were carried out for the fisheries survey. Fisheries resources of 81 species, 57 families, and 6 taxa totally were collected by shrimp beam trawl in the middle coastal ecosystem of Yellow Sea of Korea. Species were included 6 species in Bivalvia, 6 in Cephalopoda, 22 in Crustacea, 2 in Echinodermata, 5 in Gastropoda, and 40 in Pisces. Diversity indices (Shannon index, H') showed seasonal variation with low value of 2.14 in winter, and high value of 2.67 in spring. Main dominant species were Oratosquilla oratoria, Octopus ocellatus, Acanthogobius lactipes, Cynoglossus joyneri, Rapana venosa venosa, Loligo beka, Chaeturichthys stigmatias, Raja kenojei, Microstomus achne and Paralichthys olivaceus, that were occupied over 58% of total individuals, and 55% of wet weight. Fisheries organism made four coordinative seasonal groups by the principal component analysis (PCA), showing stronger seasonal variation than spatial variation. PC from PCA showed statistically significant cross-correlationships with seawater temperature, NH4-N, TP and chlorophyll a (P 〈 0.05).

Maturation and spawning of the jack mackerel, Trachurus japonicus was investigated based on the samples captured in the coastal waters around Jeju Island from January 2007 to December 2008. Gonadosomatic index began to increase in March, and reached a maximum between April to June. After spawning it began to decrease from August. Reproductive season was estimated to March-July, with peak in April. Fecundity was proportional to the size of the female, with the clutch size varying from 33,493 eggs in the smallest female(FL=27.0cm) to 627,061 eggs in the largest(FL=40.6cm). Size at 50% sexual maturity(FL50), determined from mature females, was 26.6cm FL. Annual reproductive cycles of this species could be divided into six successive stages; immature stage(September-December), nucleolus stage(January-February), yolk vesicle stage(February-March), vitellogenic stage(March-April), ripe stage(April-July) and spent stage(July-September).

To develop the artificial spawning seaweeds of the sandfish, Arctoscopus japonicus, the effects by the material type of artificial spawning seaweeds were investigated at Dongsan port in Gangwon-do from December 2006 to March 2007. Sargassum fulvellum, S. horneri, rope and net were used as materials for artificial spawning seaweeds, and the most effective thing among them was S. fulvellum. A. japonicus began to attach the egg mass to artificial spawning seaweeds when sea temperature dropped below 10℃ in December, spawned heavily when it was around 8℃ in January, and completed the behavior when it started to increase over 10℃ in February. The hatching period of eggs was estimated to be about 60 days. The middle position in artificial spawning seaweed had the highest number of egg masses and the diameter of the egg mass ranged from 25mm to 62mm. Based on the result for the effects, the artificial spawning seaweeds of A. japonicus were developed and it is possible to use them to form seaweed forests or spawning grounds of other species.

To examine species composition, abundance and biomass of demersal organisms in the East Sea, bottom trawl survey was conducted at 7 sea areas from 2005 to 2007. A total of 107 species were collected and were composed of 54 fish species, 16 crustacea, and 37 mollusks in the East Sea from 2005 to 2007. Yearly abundance per area which caught by trawl survey in the East Sea from 2005 to 2007 ranged from a high of 292,234inds./km2 in 2005 to a low of 192,092inds./km2 in 2006. The abundance by sea area showed a peak in 76 sea area, and the lowest in 63 sea area. The abundance per area by season showed a peak in summer, and the lowest in spring. The most dominant species in abundance were Clupea pallasii, Neocrangon communis, Chionoecetes opilio. Yearly biomass per area which caught by trawl survey in the East Sea from 2005 to 2007 ranged from a high of 10,322kg/km2 in 2006 to a low of 7,096kg/km2 in 2005. The most dominant species in biomass were Chionoecetes opilio, Clupea pallasii, Dasycottus setiger. The biomass by sea area also showed a peak in 76 sea area, and the lowest in 93 sea area. The abundance by season also showed a peak in summer, and the lowest in spring. As a result of cluster analysis, demersal organisms community of 76 sea area showed a large difference with other sea area, and that of summer showed a large difference with other season.

The age and growth of the sandfish, Arctoscopus japonicus were investigated from samples of the eastern sea danish seine and gill net fishery in the East Sea of Korea from February, 2004 to December, 2007. Ages were determined from annuli in otoliths and annuli were formed between December and February once a year. Also, the main spawning period was estimated to be between December and January, thus rings were considered to be annual marks. For the relationship between fork length and total weight, a multiplicative error structure was assumed because variability in growth increased as a function of the length. The relationship between fork length and total weight were TW=0.0083FL3.01(R2=0.966) for female and TW=0.0079FL3.04(R2=0.969) for male. The variability in growth was constant as a function of age, revealing an additive error structure. The von Bertalanffy growth parameters estimated by a non-linear method were L∞=31.6cm, K=0.266/year, t0=-0.835 years for female and L∞=27.7cm, K=0.273/year, t0=-0.806 years for male. Growth at age between male and female had a significant difference(P〈0.001).

Maturation and spawning of the Pacific cod, Gadus macrocephalus was investigated based on the samples captured in East Sea of Korea from April 2006 to July 2007. Gonadosomatic index began to increase in November, and reached maximum between December and January. After spawning it began to decrease from March. Reproductive season was estimated to November-February, with peak in January. Fecundity was proportional to the size of the female, with the clutch size varying from 753,985 eggs in the smallest female(TL＝58.6cm) to 9,311,520 eggs in the largest(TL＝101.0cm). Size at 50% sexual maturity(TL50%) determined from mature females was 56.3cm of TL. Annual reproductive cycles of this species could be divided into six successive stages; immature stage(March-September), nucleolus stage(September-October), yolk vesicle stage(October-November), vitellogenic stage (November-December), ripe stage and spent stage(December-February).

우리나라의 서해와 남해 연안에 분포하는 민새우는 서해 북쪽으로는 영광에서 남쪽으로 거제도까지 널리 분포한다. 거문도 인근해역에서 채집된 민새우의 암 · 수 성비는 암컷이 48.6% 로 나타났고, 이 개체군은 7월과 8월에 성숙하고, 년 1 회 신생 가입군이 발생되었다. 교미한 개체는 7월과 8월에 출현하기 시작하였고, 갑각정 13mm 이상의 전 출현 암컷의 50% 이상이 교미한 것으로 나타났고, 성숙도지수는 7-8월에 최고치를 나타내었다. 암컷의 최소 성숙개체는 갑각장 11mm이고, 성 성숙과 교미율에 의한 군성숙도 (CL50) 는 각각 갑각장 12.53mm와 12.28mm로 나타났다. 체장 빈도 자료에 의해 추정된 민새우의 수명은 암컷이 14-15개월로 나타났다. 변형된 von Bertalanffy 성장식에 의해 추정된 성장계수(K)는 암 · 수 각각 1.22/년과 2.00/년이고, 최대 갑각장 (L∞)은 암 · 수 각각 21.99mm와 15.00mm이였으며, 암컷이 수컷보다 성장이 빠르고, 큰 것으로 나타났다.

우리 나라의 서해와 남해 연안을 분포하는 꽃새우는 북쪽으로는 강화도에서 남쪽으로 사랑도까지 널리 분포한다. 본 연구에서 대상으로 한 거문도 인근해역 꽃새우의 암ㆍ수 성비는 암컷이 48.6%로 나타났고, 이 개체군은 7월과 8월에 성숙하고, 년 1회 신생 개체군이 발생되었다. 교미한 개체는 7월과 8월에 출현하기 시작하고, 갑각장 19 ㎜ 이상의 암컷에서는 반 이상이 교미한 것으로 나타났으며, 숙도지수는 7-8월에 최고치를 나타내었다. 암컷의 최소 성숙개체는 갑각장 18 ㎜이고, CL<SUB>50</SUB> 성 성숙체장과 교미체장은 각각 갑각장 18.89 ㎜와 19.19 ㎜로 나타났다. 체장 빈도 변화에 의해 추정된 거문도 개체군의 수명은 암컷 14-15개월이고, 수컷은 13-147개월 나났다. 변형된 von Bertalanffy 성장식에 추정된 성장계수(K)는 암ㆍ수 각각 1.40/년과 2.00/년이고, 최대 갑각장(L<SUB>∞</SUB>)은 암ㆍ수 각각 29.54 ㎜와 18.95 ㎜이었으며, 암컷이 수컷 보다 성장이 빠르고, 큰 것으로 나타났다.

전라남도 여수시의 거문도, 초도, 손죽도 주변해역에서 1998년 11월부터 1999년 10월까지 12회 걸쳐 새우조망에 어획된 새우류의 종조성과 계절변동을 조사하였다. 조사해역의 수심은 20∼80m이고, 이 해역의 저층 수온의 연중범위는 8.3∼21.3℃이며, 저질은 니질대 또는 사니질이었다. 조사기간 동안 채집된 새우류는 총 11과 26속 37종 702,681개체가 출현하고 우점종은 그라비새우 48.52%, 긴줄꼬마도화새우 21.83%, 민새우 11.25%, 대롱수염새우 7.24%로 나타났다. 꽃새우, 민새우, 그라비새우는 15개 전 정점에서 골고루 출현하였으며, 대롱수염새우, 산모양깔깔새우, 긴줄꼬마도화새우는 거문도 주변해역(C구역)에서 출현하였으며, 중하, 긴발딱총새우는 초도, 손죽도 주변해역(A, B구역)에서만 출현하였다. 군집구조를 나타내는 종다양도 지수, 균등도 지수, 우점도지수는 정점 13에서 0.73과 0.61로 다양성 지수와 균등도 지수 가장 높게 나타내었고, 정점 4에서 0.14, 0.11로 가장 낮은 다양성 지수와 균등도 지수를 나타내었다. 정점별 군집의 유사도에 의하면 같은 수역인 정점 1, 7에서 0.673으로 가장 유사하고, 유사도 0.25 수준에서 거문도수역 집단(정점 10, 11)과 초도, 손죽도수역집단(정점 1∼9)으로 구분되는 것으로 나타났다.

This paper focuses on the impacts of waste dumping on inorganic nutrients in the dumping area of the Yellow Sea, and the effect of an governmental regulation of pollution in dumping areas. The environmental variables and parameters of the dumping and reference areas in the Yellow Sea were measured during July 2009 and analyzed. In addition, the analyzed data for inorganic nutrients over the last 10 years were obtained from the Korea Coast Guard (KCG) and the National Fisheries Research and Development Institute (NFRDI). The chemical environment of the study area revealed increases in concentrations of inorganic nutrients, Chemical Oxygen Demand (COD), and Volatile Suspended Solids (VSS) in the bottom layer. On the contrary, the pH level was decreased. Most notably, the time series data of inorganic nutrients showed gradual increase over time in the dumping area, and thus, the oligotrophic waters trend toward eutrophic waters. The increases appears to be due to the disposal of large amounts of organic waste . In recent times, the wastes disposed at the area were largely comprised of livestock wastewater, and food processing waste water. The liquefied waste, which contains an abundance of nutrients, causes a sharp increase in concentrations of inorganic nitrogen in the dumping area. On the one hand, the dumping sites have been deteriorated to such an extent that pollution has become a social problem. Consequentially, the government had a regulatory policy for improvement of marine environmental since 2007 in the dumping area. Hence, the quality of marine water in the dumping site has improved.

The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 ㎎ O2/g·dry, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.