Gut contents analysis is essential to predict the impact of organisms on food source changes due to variations of the habitat environment. Previous studies of gut content analysis have been conducted using traditional methods, such as visual observation. However, these studies are limited in analyzing food sources because of the digestive process in gut organ. DNA metabarcoding analysis is a useful method to analyze food sources by supplementing these limitations. We sampled marine fish of Pennahia argentata, Larimichthys polyactis, Crangon affinis, Loligo beka and Sepia officinalis from Gwangyang Bay and Yeosu fisheries market for analyzing gut contents by applying DNA metabarcoding analysis. 18S rRNA v9 primer was used for analyzing food source by DNA metabarcoding. Network and two-way clustering analyses characterized the relationship between organisms and food sources. As a result of comparing metabarcoding of gut contents for P. argentata between sampled from Gwangyang Bay and the fisheries market, fish and Copepoda were analyzed as common food sources. In addition, Decapoda and Copepoda were analyzed as common food sources for L. polyactis and C. affinis, respectively. Copepoda was analyzed as the primary food source for L. beka and S. officinalis. These study results demonstrated that gut contents analysis using DNA metabarcoding reflects diverse and detailed information of biological food sources in the aquatic environment. In addition, it will be possible to provide biological information in the gut to identify key food sources by applying it to the research on the food web in the ecosystem.

To investigate the trophic relationship between the fresh water fishes and aquatic invertebrates, the research of their prey is important. However, the morphological identification of the prey in the fish intestine is very difficult due to the process of digestion. Thus, we conducted the DNA barcoding methods for aquatic insect samples from the gut of fresh water fishes for identifying hardly recognizable species. All benthic macroinvetebrates and manchurian trouts were collected from the upper streams of Inje-gun, Korea, in spring and summer, 2013. A total of 27 unique taxa were recognized, among which 23 species were identified by morphology, and 4 unrecognizable individuals were identified based on mitochondrial cytochrome C oxidase I (Mt-COI). As the results of this study, Ephemerella sp., Neophylax sp., Neophylax sp., and Pteronarcys sp. are verified to the genus level by DNA barcoding.