Keragaman, Distribusi dan Kelimpahan Chaetognatha di Kawasan Pesisir Kota Dumai Provinsi Riau

Chaetognatha or arrow worms are one of the holoplankton groups whose distribution and diversity is quite high in waters. Chaetognatha has important role in the food chain and also functions as a bioindicator of oceanographic conditions. The abundance of Chaetognatha in the waters can affect the abundance of fish larvae and other zooplankton, so that information on its existence is very important in fisheries management. The aims of study to determine the diversity, distribution and abundance of Chaetognatha in the coastal waters of Dumai City, Riau Province. This research was conducted from April to September 2021 in the coastal waters of Dumai City. The number of sampling stations are three points and the number of samplings twice at each station. The number of Chaetognatha species in the coastal waters of Dumai City is relatively low, only 2 species were found, namely Eukronia calliops and Sagitta megalopthalmus. The distribution of Chaetognatha in the waters of Dumai City was quite even and found in three sites, although the abundances were relatively different. The abundance of Chaetognatha ranges from 19-322 ind/1000 m 3 , it is very low compare to other research.