Penelitian terkait reproduksi ikan khususnya tentang Lm dan Lc pada hasil tangkapan rawai dasar yang ada di Pulau Tarakan perlu dilakukan pengkajian, guna menjaga kelestarian dan keberadaan populasi ikan yang ada di perairan. Tujuan penelitian untuk mendapatkan data ukuran panjang total dan standar serta berat ikan, mendapatkan data karakteristik dan tingkat kematangan gonad ikan, serta menjelaskan ukuran pertama kali matang gonad dan ukuran pertama kali tertangkap ikan hasil tangkapan utama perikanan rawai dasar yang didaratkan di Kota Tarakan. Metode penelitian menggunakan metode observasi dengan pengamatan dan pengukuran ikan hasil tangkapan rawai dasar. Penelitian dilaksanakan pada bulan Januari-Maret 2021. Hasil pengukuran sampel ikan Arut (Pomadasys sp) diperoleh kisaran panjang total 24,7-51,9 cm, berat berkisar 237-2150 gram dan panjang standar 18,8-40,3 cm. Sampel ikan Kakap Merah (Lutjanus sp) diperoleh kisaran panjang total 32,0-50,8 cm, panjang standar 25,8-45,2 cm dan berat berkisar 509-2640 gram. Hasil pengamatan karakteristik Tingkat Kematangan Gonad (TKG) sampel ikan Arut (Pomadasys sp) berada pada TKG I-V dan sampel ikan Kakap Merah (Lutjanus sp) diperoleh TKG I-III. Hasil pengukuran Lm dan Lc sampel ikan Arut (Pomadasys sp) diperoleh nilai Lm > Lc (Lm = 30,17 cm; Lc = 25,98 cm) dan nilai Lm dan Lc pada sampel ikan kakap merah (Lutjanus sp) menunjukan Lm > Lc (Lm = 41,51 cm; Lc = 36,39 cm).
Kata Kunci: Ikan Arut, Ikan Kakap Merah, Panjang Pertama Matang Gonad dan Tertangkap, Perairan Tarakan

Research related to fish reproduction, Lm and Lc in bottom longline catches on Tarakan Island needs to be studied to sustain the fish populations’ sustainability and continuation in the waters. The purpose of the study was to obtain data on the total and standard length and weight of fish, obtain data on the characteristics and maturity level of fish, as well as explain the size of the first gonad maturity and the size of the first caught fish from the main catch of the basic longline fishery landed in Tarakan City. The research method used the observation method by observing and measuring the fish caught in the bottom longline. The study was conducted from january to march 2021. The samples measurement result of arut fish (Pomadasys sp) obtained a total length range of 24,7-51,9 cm; weight ranged from 237-2150 grams and standard length 18,8-40,3 cm. while red snapper (Lutjanus sp) took a total length range of 32,0-50,8 cm, standard length 25,8-45,2 cm, and weight ranged from 509-2640 grams. The characteristic observation results on the gonad maturity level of arut fish (pomadasys sp) were at gonad maturity level I-V and Red snapper (Lutjanus sp) was only at Gonad Maturity Level I-III. The Lm and Lc measurement result showed Arut Fish resched (Lm= 30,17 cm; Lc= 25,98 cm) and red snapper recorded Lm > Lc (=41,51 cm; Lc = 36.39 cm). Keywords: Arut Fish, Red Snapper, First Length of Gonad Ripe and Caught, Tarakan Waters