한국 섬진강 하구 어류 종조성의 계절변동 및 주요우점종의 생식생태

Abstract

Seasonal variation of fish species composition and reproduction of six dominant species (Clupea pallasii, Konosirus punctatus, Leiognathus nuchalis, Mugil cephalus, Pleurnectes yokohamea, Sillago japonica) were investigated at the three stations (St. 1: upstream, St. 2: entrance of river, St. 3: coast) in the Seomjin River estuary from May 2009 to February 2010. During the study period, thermocline was weakly developed at St. 2 and in November; halocline was strongly developed at St. 2 and in August. A total of 36 species of 24 families under 8 orders were indentified. The number of species was the highest in August (19 species) and at St. 3 (30 species); the lowest in February (14 species) and at St. 2 (8 species). The dominant species were Leiognathus nuchalis (19.4%), Trachurus japonicus (19%), Tribolodon hakonensis (13.5%), Lateolabrax maculatus (5.3%) and Mugil cephalus (5.1%). The dominant species at each station were Tribolodon hakonensis (67.7%), Mugil cephalus (11.7%) and Chelon haematocheilus (4.5%) at St. 1, Tribolodon hakonensis (20%), Acanthogobius hasta (13.3%) and Konosirus punctatus (13.3%) at St. 2 and Leiognathus nuchalis (24.3%), Trachurus japonicus (24%) and Lateolabrax maculatus (6.1%) at St. 3. The principal component analysis (PCA) based on species composition showed that the three groups were identified; the first group included spring, summer, fall and winter of both St. 1 and St. 2, the second group included spring and summer of St. 3 and the third group included fall and winter of St. 3. The regression analysis between PCA scores and environmental factors suggest three grouping phenomenon may be related to salinity. As a result of histological observation of gonadal tissue, the Seomjin River estuary may be available as a spawning area for some species such as Clupea pallasii and Pleuronectes yokohamae even in a temporary investigation.