Penelitian mengenai struktur komunitas Polychaeta di lima muara sungai Teluk Jakarta (Muara Karang, Muara Baru, Muara Sunda Kelapa, Muara Tiram, dan Muara Tawar) telah dilakukan. Sampel diambil menggunakan Peterson Grab Sampler dari tiga stasiun di masing-masing lokasi pengambilan sampel. Berdasarkan hasil identifikasi dan pencacahan sampel diperoleh 29 marga yang terdiri dari 16 marga berasal dari subkelas Errantia dan 13 marga lainnya berasal dari subkelas Sedentaria. Kapadatan Polychaeta di perairan Teluk Jakarta berkisar antara 194,22?296,30 individu/m2. Terdapat dominasi marga Capitella di Muara Tawar, dan dominasi marga Nereis di Muara Karang. Indeks keanekaragaman Polychaeta berkisar antara 0,69--2,71 dan indeks kemerataan berkisar antara 0,09- -0,97. Kesamaan marga Polychaeta antar muara bervariasi yang berkisar antara 0- -1. Sebaran Polychaeta di perairan Teluk Jakarta menunjukkan pola mengelompok.

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Research on community structure of Polychaeta in five rivermouths of Jakarta Bay (Muara Karang, Muara Baru, Muara Sunda Kelapa, Muara Tiram, and Muara Tawar) have been performed. Samples were taken by Peterson Grab Sampler from three stations at each sampling sites. Based on the identification and enumeration of samples obtained, there were 29 genera comprising, 16 genera from subclasses Errantia and 13 other genera from subclasses Sedentaria. Density of Polychaeta in Jakarta Bay ranged from 194,22 to 296,30 individu/m2. Polychaeta in Muara Tawar are dominated by the Capitella, and then Polychaeta in Muara Karang are dominated by the Nereis. Polychaeta diversity index ranged from 0,69 to 2,71 and evenness index ranged from 0,09 to 0, 97. The similarity index at Jakarta Bay ranged from 0--1. Distribution of Polychaeta in Jakarta Bay waters showed clumped patterns.