An ecological study for species composition and abundance of the fish assemblages in the coastal waters of Gujora and Mangchi of Geoje, Korea was conducted using monthly larval collection by an RN80 net from June, 2018 to May, 2019. A total of the 5 Orders, 15 Families, 21 species were collected. The dominant species were Ammodytes japonicus and Engraulis japonicas. Gobiidae was the most dominant species in June, Spratelloides gracilis in July, Chelidonichthys sp. in August, Gobiidae in September, Repomucenus beniteguri in October, Sebastiscus marmoratus in November, Sebastiscus marmoratus and Hexagrammos otakii in December of 2018, Pleuronectes yokohamae in January, Ammodytes japonicus in Febraury, Engraulis japonicus in March, Sebastes sp. and Gobiidae in April and Engraulis japonicus in May of 2019. The highest number of species and individuals were found in July and the smallest in August. Thus, the diversity index was the highest in July and the lowest in August. As a result of the similarity by month was divided into Group I in January and February and Group II in April, June and September. The most dominant species in the Group I were the Ammodytes japonicus and Sebastes inermis, and the most dominant species in the Group II was Gobiidae.

• 강다연(경상대학교 해양식품생명의학과/해양산업연구소/해양생물교육연구센터) | Da-Yeon KANG (Department of Seafood & Aquaculture Science/Institute of Marine Industry/Marine Bio-Education & Research Center, College of Marine Science, Gyeongsang National University)
• 남기문(부경해양생물연구소) | Ki-Mun NAM (Pukyong Marine Life Institute)
• 최옥인(한국수산자원관리공단 남해본부) | Ok-In CHOI (Korea Fisheries Resources Agency, South Sea Branch)
• 김병섭(한국수산자원관리공단 남해본부) | Byeong Seop KIM (Korea Fisheries Resources Agency, South Sea Branch)
• 연인호(한국수산자원관리공단 남해본부) | In-Ho YEON (Korea Fisheries Resources Agency, South Sea Branch)
• 김기둥(한국수산자원관리공단 남해본부) | Ki-Doong KIM (Korea Fisheries Resources Agency, South Sea Branch)
• 백근욱(경상대학교 해양식품생명의학과/해양산업연구소/해양생물교육연구센터) Corresponding author