Lobster merupakan hasil produk utama perikanan di indonesia dengan kategori potensial dan memiliki ekonomis penting untuk ekspor. tujuan penelitian ini adalah untuk mengetahui struktur ukuran dan tingkat kematangan gonad lobster pakistan (panulirus polyphagus) dan lobster mutiara (panulirus ornatus) hasil tangkapan jaring insang di perairan tarakan. penelitian ini menggunakan metode deskriptif kuantitatif dan kualitatif dengan pengambilan sampel selama 2 bulan dalam 3 kali sampling perminggu. hasil penelitian didapatkan sampel sebanyak 27 pakistan dan 8 mutiara. hasil analisa struktur ukuran panjang total lobster pakistan ditemukan kisaran 8.7 - 30.4 cm dan lobster mutiara ditemukan panjang total kisaran 16 - 27.6 cm. hasil analisa ukuran panjang karapas dari lobster pakistan didapatkan kisaran 5.9 – 12 cm dan lobster mutiara didapatkan panjang karapas kisaran 6.7 - 10.9 cm. hasil analisa dari ukuran panjang abdomen lobster pakistan didapatkan kisaran 6.3 - 13 cm dan lobster mutiara ditemukan panjang abdomen kisaran 6.5 - 10.7 cm. hasil penelitian dari berat lobster pakistan didapatkan kisaran 108 - 928 gram dan lobster mutiara ditemukan berat kisaran 147 - 583 gram. kata kunci: lobster pakistan, lobster mutiara, struktur ukuran

Lobster is the main product of fisheries in indonesia with potential category and is economically important for export. the purpose of this study was to determine the size structure and gonad maturity level of pakistan lobster (panulirus polyphagus) and mutiara lobster (panulirus ornatus) caught by gillnet in tarakan waters. this study applied quantitative and qualitative descriptive methods with sampling for 2 months in 3 sampling times per week. the results of the study obtained a sample of 27 pakistanis and 8 mutiaras. the results of the structural analysis of the total length of pakistan lobster were found in the range of 8.7-30 4 cm and mutiara lobsters were in the range of 16-27 6 cm. the results of the analysis of the carapace length of pakistan lobsters were in the range of 5 9-12 cm and mutiara lobsters were in 67 10.9 cm. the results of the analysis of the abdominal length of the pakistani lobster were found in the range of 6 3-13 cm and the mutiara lobster was in the range of 6 5 - 107 cm. the results of the research on the weight of the pakistan lobster were found in the range of 108-928 grams and the mutiara lobsters were in the range of 147-583 grams. keywords: panulirus polyphagus, panulirus ornatus, size structure