Determination of spatial and individual variations in the dietary composition of Pennahia argentata in coastal waters of South Korea using metabarcoding and morphological analyses

Abstract

Understanding the feeding ecology of dominant fish species can be accomplished by considering on spatial and individual variations in prey composition. This study aimed to characterize the diet and feeding habits of Pennahia argentata (silver croaker, a common sciaenid fish in the southern coastal seas of Korea) by analyzing the gut contents of individuals. Morphological and metabarcoding identifications were applied to 92 and 94 gut samples collected from four stations in Gwangyang Bay in September 2018, respectively. P. argentata was the dominant species at all stations. The most common prey species was shrimp, as determined by both morphological (38.8%F) and metabarcoding (233.3%F) analyses. The phylum-level dietary profiles were similar among the individuals at different sites, but the species-level dietary profiles varied among the individuals at different sites and were distinguished by the read abundance of Oratosquilla oratoria (mantis shrimp) and Aliaporcellana sp. (crab). P. argentata is mostly generalized and mixed in its feeding habit, with varying frequencies of occurrence of two important prey items, O. oratoria and Aliaporcellana sp., and degrees of specialization on several items among the sites and size groups. Regardless of the relatively small spatial scale, the DNA metabarcoding analyses identified compositional variations in the gut contents of P. argentata. These variations appeared to be associated with water quality variables (total organic carbon, total nitrogen, and total phosphorus) and individual characteristics (body length and weight), but not with fish community traits (diversity, dominance, and evenness). Our results demonstrate the usefulness of gut content eDNA analyses for evaluating biodiversity in fish diets and the describing feeding strategies of fish.