The diet composition of Takifugu niphobles was studied with 587 specimens collected in the eelgrass bed of Jangpyeong-ri, Tongyeong, Korea, using a seine net, monthly from May 2016 to April 2017. The standard length (SL) of the specimens ranged from 0.7 to 9.0 cm. The stomach contents analysis indicated that T. niphobles consumed mainly amphipods (%IRI: 91.0 %). In addition, T. niphobles fed on small quantities of copepods, polychaetes, insects, bivalves and crabs. T. niphobles consumed mainly amphipods over all size class. Smaller individuals (less than 4 cm SL) fed mainly on amphipods and copepods. The proportion of copepods decreased, as body size increased, whereas the consumption of polychaetes increased gradually. The seasonal variation in the diet composition of T. niphobles was significant. Amphipods were most common prey in all seasons. Copepods decreased from summer to spring gradually whereas the consumption of polychaetes increased in autumn.
The feeding habits of juvenile Chaenogobius annularis were examined based on gut content analysis of 281 individuals, collected from May to June 2011 in the coastal water of Geoje, Korea. Copepods were the main source of food for C. annularis, which constituted 61.6% in IRI. Barnacle larvae was the second largest dietary component. Graphical analysis of the diet composition showed that C. annularis was a specialized predator characterized by strong individual feeding specialization. Both small and large size class of C. annularis mainly consumed harpacticoida and cirripedia cypris.
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.
가시망둑(1.80~10.01 cm TL)의 성장과 생산량에 대한 연구를 동대만 잘피밭에서 2006년도에 실시하였다. 가시망둑 시료는 소형 빔트롤로 총 702개체를 채집하였다. 본 연구 결과, 가시망둑에 대한 전장(TL)의 성장식은 TL=0.0539 d0.9105, 전장과 체중의 관계식은 W=0.0079 TL3.1103 이었다. 가시망둑의 단위면적당 밀도, 생체량, 일일생산량, 연간생산량은 각각 0.06±0.062/m2, 0.10±0.144 g/m2, 0.0005±0.0006 g AFDW/m2/day, 0.1833 g AFDW/m2/year이었으며, P/B의 비율은 1.813이었다. 가시망둑 생산량은 생체량의 높았던 5월과 7월 9월에 가장 높았으며(0.0029, 0.0031, 0.0019 g AFDW/m2/day), 생체량이 낮았던 12월에 가장 낮았다(0.00004 g AFDW/m2/day). 가시망둑의 월별 생산량의 변화에서 양의 상관관계를 보인 것은 생체량과 수온이었다.
A total of 164 individuals of Hippocampus coronatus were collected from an eelgrass bed in Dongdae Bay, Korea from September 2006 to August 2007. The number of individuals of H. coronatus was higher in September 2006. The size of H. coronatus ranged from 2.4 to 9.3cm in height (Ht), and most of individuals were small size below 5cm (Ht). H. coronatus was a carnivore which consumed mainly gammarid amphipods and copepods. Its diets also included a small amount ofmysids, ostracods, brachiopods, caprellid amphipods, bathynellaceas, isopods, tanaids, and ascothoracids. The diets of H. coronatus underwent size-related changes; smaller individuals consumed copepods, while larger individuals ate gammarid amphipods and mysids. The dietary breadth index of H. coronatus was increased with increasing of their size.
실비늘치(6.70~5.32 cm TL)의 성장과 생산량에 대한 연구는 동대만 잘피밭에서 2006년도에 실시하였다. 실비늘치 시료는 소형 빔트롤에 의해서 총 888개체가 채집되었다. Bertalanffy 성장식을 이용하여 구한 전장의 성장식은 Lt=24.8257(1-e-0.5583(t+0.4816))이었다. 실비늘치의 밀도, 생체량, 일일생산량, 연간생산량, 그리고 P/B ratio는 각각 0.01±0.009/m2, 0.17±0.16g/m2, 0.00006±0.00006g AFDW/m2/day, 0.02g AFDW/m2/yr, 그리고 0.12이었다. 실비늘치 생산량의 월변화는 컸으며, 7월(0.000182g AFDW/m2/day), 9월(0.000127g AFDW/m2/day) 그리고 11월(0.000123g AFDW/m2/day)에 높았으며, 4월과 5월(0.000003g AFDW/m2/day)에 가장 낮았다. 실비늘치의 생산량의 월변화는 개체수와 생체량, 그리고 성장률과 양의 상관관계를 보였다.
진동만 잘피밭에서 서식하는 대형 부착해조류는 총 3종이었으며, 출현종은 갈조류의 Scytosiphon lomentaria, Colpomenia sp., 그리고 홍조류의 Gracilaria sp., 으로 구성되어 있었다. 한편 미세 부착해조류는 Cocconeis scutellum와 Cocconeis placentula가 우점하였다. 잘피에 부착하여 서식하는 부착해조류의 현존량은 계절 변동이 뚜렷하게 나타났다. 대형 부착해조류는 2003년 11월에 3.3 g DW/m2, 미세 부착해조류는 2003년 6월에 43,153 cells/m2를 보이며 가장 높게 나타났다. 다른 해역의 잘피밭(광양만, 동대만 및 앵강만)과 비교해보면, 본 조사해역의 잘피밭에서 서식하는 부착해조류의 종 다양성 및 현존량이 매우 낮게 나타나 특이하였다. 이와 같은 결과는 잘피밭의 물리학적인 환경특성(예를 들면 조류 및 유속), 잘피 자체의 생물학적인 특성, 그리고 수질의 악화에 기인하였다.