Penelitian ini dilaksanakan pada bulan April-Juli 2015 di Rumah Akuakultur Laboratorium Biologi Kelautan, FMIPA UI dan bertujuan : (1) Mengetahui pengaruh perbedaan persentase Sargassum sp. pada komposisi pakan buatan terhadap pertambahan biomassa, panjang dan kelangsungan hidup ikan bandeng (Chanos chanos) dalam akuaponik air laut. (2) Mengetahui pertambahan biomassa Gracilaria sp. dalam akuaponik air laut. Ikan bandeng yang diteliti berukuran 3,57-4,13 cm dengan kepadatan 20 ekor/bak dan Gracilaria sp. yang ditanam memiliki biomassa 30 gram/bak. Penelitian ini berlangsung 60 hari dengan 3 perlakuan berbeda, yaitu : perlakuan pakan komposisi (0% Sargassum sp., 6% Sargassum sp. dan 12% Sargassum sp.). Setiap perlakuan dilakukan 3 ulangan. Hasil penelitian menunjukkan pengaruh perbedaan persentase Sargassum sp. dalam pakan buatan. Komposisi 12% Sargassum sp. yang paling berpengaruh nyata terhadap pertambahan biomassa dan panjang ikan bandeng, sedangkan untuk kelangsungan hidup ikan bandeng tidak berpengaruh. Pertambahan biomassa Gracilaria sp. paling berpengaruh terjadi di bak kultur yang perairannya bersumber dari sisa konsentrasi pakan komposisi 12% Sargassum sp. dalam sistem akuaponik air laut.

---

This research was conducted in April to July, 2015 in Aquaculture House of Marine Biology Laboratory of FMIPA, UI. The aims of this research are : (1) Discover the impact of different Sargassum sp. percentage in artificial feed composition to biomass growth, length, and survival of milkfish. (2) Discover biomass growth of Gracilaria sp. in Marine Aquaponic. The objects of this research are 3,57-4,13 cm of milkfish (Chanos chanos) which are placed in a pond (each pond consists of 20 milkfish) and Gracilaria sp. whose biomass is 30 gram/in each pond. This research was conducted in 60 days, by giving 3 different feed compositions to the fish 3 times (0% Sargassum sp., 6% Sargassum sp. and 12% Sargassum sp.). This research found the impact of different Sargassum sp. percentage in artificial feed. 12% composition of Sargassum sp. shows the best impact to the growth of biomass and milkfish length. However, it does not show any impact to the survival of milkfish. The Gracilaria sp. biomass growth is most visible in culture pond. The water of the pond sourced from the concentrate of 12% feed composition of Sargassum sp. in marine aquaponic system.