엽상자어(Leptocephalus)는 뱀장어목(Anguiliformes)에 속하는 어류의 자어로 5~6월에 우리나라 남해안 일대의 정치망에서 멸치와 함께 어획 후 방류하지만 대부분 폐사하는 실정이다. 따라 서 본 연구의 목적은 멸치어업을 하는 정치망에서 무분별하게 포획되는 엽상자어의 종을 구명 하여 수산자원보호 및 이들 자치어 생태 연구를 위한 기초 생물학적 자료를 제시하고자 수행 하였다. 실험에 사용된 엽상자어는 5~6월에 남해의 정치망에서 채집하였으며, 외부형태와 유 전학적 특성을 붕장어(Conger myriaster), 갯장어(Muraenesox cinereus) 및 뱀장어속(Anguilla) 4종의 성어와 비교하였다. 유전학적 분석은 추출한 DNA를 12s rRNA, 16s rRNA 부분단편을 PCR로 증폭하여 염기배열을 분석한 후 분자계통수를 작성하여 장어류 유생이 붕장어, 갯장어 및 뱀장어속 4종 중 어느 쪽의 성체와 클러스터 그룹화를 이루는지 계통학적 유연관계를 확 인하였다. 엽상자어의 외부형태 계수 및 계측결과 엽상자어의 전장에 대한 머리길이의 백분비 와 뒷지느러미 기점거리의 백분비는 붕장어와 가장 유사한 비율을 보였고, 척추골수 역시 붕 장어와 가장 유사하였다. 또한 엽상자어의 유전자 분석결과는 모두 붕장어 성체와 클러스터 그룹화를 이루는 것을 확인함으로서 남해안에서 5~6월에 어획되는 엽상자어는 모두 붕장어의 자어임을 할 수 있었다.

본 연구는 붉바리 어미의 사육환경에 따른 난질의 변화를 난의 생화학적 분석을 통하여 난질 에 영향을 미칠 수 있는 요소를 구명하기 위하여 수행하였다. 그 결과 육상수조에서 사육하는 것보다 해상가두리에서 사육할 때 부상률, 수정률, 난 발생 생존율 및 부화율이 우수하였다. 그 리고 해상가두리에서 생산한 수정란의 유리아미노산의 함량이 높았다. 즉, 해상가두리에서 사 육관리할 때 난질이 우수한 수정란을 생산할 수 있고, 난질이 우수할수록 유리아미노산의 함 량이 높았다.

말쥐치는 북서태평양 해역에 분포하는 군집성 어류로 수산식품으로 이용되는 경제적 가치가 높은 어종이다. 본 연구에서는 서남해에 서식하는 국내산 말쥐치 (Thamnaconus modestus)와 기존에 보고된 유사종 (Thamnaconus septentrionalis) 과의 형태적-유전적 특징을 비교-분석하였다. 이를 위해 서남해에서 채집한 말쥐치의 외부 형태와 골격을 관찰하고, 미토콘드리아 DNA의 cytochrome c oxidase subunit I (COI) 유전자 염기서열을 비교하여 유사종 (T. septentrionalis)과의 계통진화적 연관관계를 분석하였다. 서남해안 말쥐치의 외부 형태는 회갈색 바탕에 몸 전체에 흑갈색 무늬가 불규칙하게 산재된 패턴을 가지며 청록빛의 지느러미가 관찰되었다. 채집한 말쥐치에서 추출한 미토콘드리아DNA의 COI 유전자 분석결과 7종류의 염기서열 변이가 나타났으나 상동성이 전체적으로 98.8% 이상으로 유사 성이 높게 나타났다. 또한 형태적으로 말쥐치 유사종인 T. septentrionalis COI 염기서열 비교와 계통유전학적 분석 결과, 보고된 시퀀스 중 상동성이 99%로 유전적으로 말쥐치로 보여지는 두 종 (JN813099, MW485059)과 상동성 95%로 유사종으로 보이는 두 종 (EF607583, KP267619)이 확인되었다. 말쥐치와 유사종은 계통유전적 분석결과 말쥐치와 유사종의 차이를 확인하였으나 형태적 특징으로 종 분류는 어 려운 상태이다. 따라서 본 연구는 말쥐치의 외부 형태와 내부 골격 및 계통유전학적 정보를 제공함으로 말쥐치와 유사종 (T. septentrionalis)의 분류학적 재검토를 진행하는 데 주요한 정보가 될 것이다.

Monthly fluctuation in abundance and species composition of fish in coastal waters off Oenaro island, Goheung were investigated using seasonal samples collected by a shrimp beam trawl in 2018. A total of 5,981 fishes were sampled and classified into 48 species, 32 families, and 9 orders. The dominant species was Engraulis japonicus (993 individuals, 16.60%), Amblychaeturichthys hexanema (844 individuals, 14.11%), and Thryssa kammalensis (674 individuals, 11.27%). The highest number of individuals was found in August (958 individuals), while the lowest number of individuals was found in January (136 individuals). The diversity index was the highest in November (H’ = 2.37) and the lowest in January (H’ = 1.77).

본 연구는 붉바리 배란유도를 위해 다양한 호르몬과(ovaprim, pimozide, LHRHa, HCG)과 LHRHa 의 농도별 효과를 조사하였다. LHRHa는 50 μgkg-1, 100 μgkg-1, 150 μgkg-1, 200 μgkg-1의 농 도로 처리하였다. 호르몬은 등 근육에 주사하였으며, 조사 결과 LHRHa 단독, 그리고 LHRHa와 Pimozide를 혼합하여 투여했을 때 가장 효과적이었으며, 두 실험구 사이의 차이는 거의 없는 것으로 나타났다. 따라서 LHRHa를 단독으로 사용하는 것이 가장 효율적인 것으로 판단된다. 그리고 LHRHa를 다양한 농도로 처리하여 배란유도 효과를 조사한 결과 100 μgkg-1의 농도로 투여했을 때 가장 우수한 것으로 조사되었다.

The ichthyoplanktons were sampled by Bongo net to study the distribution of the eggs and larvae in the West coastal waters of Korea during the study period (February, May, August and October of 2017). Collected fish eggs were divided into Engraulis japonicus and unidentified species. The most dominant species, Engraulis japonicus accounted for 79.52% of the total fish egg, which was followed by unidentified species (20.48%). The total of 36 taxa in fish larvae were identified based on morphological and molecular characteristics. Fish larvae were dominant by Gobiidae species. 48.30% of the total catch in abundance, which was followed by Engraulis japonicus (31.86%). These two taxa composed 80.16% of the total collected fish larvae. The seasonal diversity index of species from the collected fish larvae in the West coastal waters in 2017 was 0.625-1.883 and the evenness index was 0.380-0.865. In addition, dominance index was 0.618-0.920 and richness was 0.573-3.189.

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.

The ichthyoplanktons were sampled to study distribution of the ichthyoplankton in coastal waters of Nanji-Island in August and November 2015 and January and May 2016. During the study, fish eggs of eight different species were collected. Engraulis japonicus was the most dominant species which accounted 44.80%. Sebastes schlegeli comprised 31.39% of the total larvae and juveniles. The diversity index of species per month of the collected juveniles at Nanji Island from 2015 to 2016 was 0.598-1.770 and the evenness index was 0.432-0.761. In case of dominance index was 0.619-0.897 against the evenness index. The analyzed species diversity index by the each station was 0.818-1.945 and the dominance index was 0.492-0.897 against the species diversity index. The months of August and May exhibited similar results. In addition, the community structure was very similar in state 2 and state 3.

The fluctuation in the abundance and species composition of fish was investigated using gape net in Dolsan District of Yeosu Korea from July 2015 to April 2016. A total of 1,331 fishes were sampled and classified into 30 orders, 42 families, and 53 species. The dominant orders are Perciformes including 21 famailies and 24 species, followed by Scorpaeniformes including 7 families and 13 species, and Clueiformes including 6 families and 6 species. Among the 53 fish species collected, Engraulis japonicus was the most frequent species occupying 43.5%, followed by Argyrosomus argentatus (23.8%), and Leiognathus nuchalis (22.4%). The monthly diversity, evenness, and richness index were 1.83-2.90, 0.76-0.95 and 3.06-6.40.

The purpose of this study is to compare the ichthyofauna between the eelgrass bed waters located in the open sea and the nearby sea free of eelgrass, and this study collected a total of 26 species. Comparing the fish collected on the eelgrass bed (St.2) of Geomun–do coast with the fish collected on the coastal waters (St.1) void of the nearby eelgrass bed, the fish collected from the eelgrass bed included 19 species, 413 individual with 16,110.6g in weight while the fish collected from the coastal waters void of the eelgrass bed included 19 species, 290 individuals with 12,961.5g in weight. Accordingly, it was found that the population size and biomass of the fish collected from the eelgrass bed were higher than the coastal waters void of the eelgrass. This study could identify that diversity, richness, evenness index except dominance were also much higher even in the result of cluster analysis.

Monthly variation in abundance and species composition of the fishes were investigated based on specimens collected by gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010. The collected fishes were 1,529 individuals (183,840g) of the total, identified into 6 orders, 16 families and 24 species. The most dominant order fish was Perciformes comprised 9 species, 7 families, and followed Pleuronectiformes comprised 5 species, 3 families, Scorpaeniformes comprised 5 species, 2 families. These 3 orders constituted 81.1% of the total collected fish. During the study, most dominant species was Hexagrammos otakii accounted for 189 individuals (12.4%) of the total, followed by Lateolabrax japonicus 165 individuals (10.8%), Hexagrammos agrammus 154 individuals (10.0%). The fish was collected by a gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010, the diversity index of the fishes was 2.09~2.66, which was the highest in August, 2010 and the lowest in February, 2010. The evenness index of them was 0.84~0.89, which was the highest in August, 2010 and the lowest in February, 2010 and the richness index of them was 2.02~3.14, which was the highest in October, 2009 and the lowest in February, 2010. The analyzed species diversity index by the each stations was 2.47~2.66 and the evenness index was 0.84~0.90 and the richness index 2.99~3.37. The similarity of community structure per season was very high which was the least in spring and fall. In addition, the community structure was very similar in state 3 and 2 out of each stations.