Perairan timur kota tarakan memiliki potensi sumberdaya perikanan yang sangat berlimpah. salah satu sumberdaya perikanan yang ada yaitu kepiting bakau (scylla serrata). penelitian ini bertujuan mengetahui pertumbuhan allometri, indeks kondisi dan rasio kelamin di perairan timur kota tarakan. metode yang digunakan dalam penelitian ini adalah metode deskritif dengan pendekatan kuantitatif. pengambilan sampel dilakukan pada bulan november 2017. hasil penelitian didapatkan pertumbuhan scylla serrata jantan dan betina berdasarkan (hubungan panjang karapas dan berat total),(hubungan lebar karapas dan berat total) dan (hubungan tebal kepiting dan berat total) bersifat allometri negatif. nilai tertinggi indeks kondisi berdasarkan (hubungan panjang karapas dan berat total) pada scylla serrata jantan bentuk tubuh gemuk 52% dan betina bentuk tubuh gemuk 50%, (hubungan lebar karapas dan berat total) jantan bentuk tubuh kurus 52% dan betina bentuk tubuh gemuk 50% dan berdasarkan (hubungan tebal kepiting dan berat total) jantan memiliki bentuk tubuh kurus 52% dan betina bentuk tubuh gemuk sebesar 50%. rasio kelamin dari scylla serrata jantan 55% dan betina 45% atau 1,3:1. kata kunci: pertumbuhan, indeks kondisi, rasio kelamin, scylla serrata, perairan timur tarakan

The waters of east in tarakan city has abundant fishery resource potential. one of the existing fishery resources is mangrove crab (scylla serrata).the objective of this study to know the growth of allometric,index condition and sex ratio in the water of tarakan city. the method of this study was descriptive method with quantitative approach.the sample was conducted in november 2017.the results showed that growth of male and female scylla serrata was based on (relationship of carapace length and total weight),(relationship of carapace width and total weight) and (relationship of carapace width and total weight) and (relationship of thick crab and total weight) has negative allometri. the highest value of index condition based on (relationship of carapace length and total weight) the male of scyla serrata that has the fat body shape of 52% and female have the fat body shape of 50%. (relationship of carapace width and total weight) male have skinny body shape of 52% and female have the fat body shape of 50%. (relationship of thick crab and total weight) male have a skinny body shape of 52% and female have a fat body shape of 50%. the sex ratio of male scylla serrata were 55% and female 45% or 1,3:1. keywords: growth, index conditions, sex ratio, scylla serrata, the water of east tarakan