AbstrakKeputusan Menteri No.2 2015 telah melarang semua trawl dan pukat tarik. Untuk mengimbangi kerugian tersebut, Kementerian Kelautan dan Perikanan mengeluarkan jaring insang millenium (3,5 inci) dan memberikannya untuk nelayan. Penelitian ini bertujuan untuk mengevaluasi selektivitas alat tangkap jaring insang millenium yang diluncurkan, yang menargetkan ikan kembung (Rastrelliger brachysoma) dalam hasil tangkapannya. Penelitian dilakukan di Selat Madura, dengan membandingkan jaring insang millennium dengan jaring insang biasa (2,0 inci). Hasilnya menunjukkan kedua alat tangkap tersebut memiliki kategori panjang yang sama (18,28 ± 0,707951 untuk jaring insang millenium, dan 18,78 ± 0,92655 untuk jaring insang biasa). Semua ikan kembung (Rastrelliger brachysoma) yang tertangkap ditemukan pada tahap kematangan penuh (tingkat kematangan III atau IV). Jaring insang umum menghasilkan biomassa tangkapan yang jauh lebih tinggi daripada jaring milenium (632 ekor), dikarenakan ukuran jaring yang lebih kecil. Jadi, kedua alat tangkap tersebut dianggap selektif untuk menangkap ikan kembung. Agar dapat diterima, diperlukan pengurangan ukuran jaring untuk jaring insang millenium.Kata kunci : Gillnet millenium, selektivitas, kematangan gonad.

Barbodes binotatus is an endemic species and most dominant freshwater fish in Indonesia. This prelilinary study aimed to calculate genetic differences of the species from three different rivers in Java island. A total of 90 specimens were collected from each river and a total of 26 sequences were analyzed using mitochondrial DNA (mtDNA) region Cytochrome Oxidase Subunit I (COI). BLAST analysis showed > 97 % similarity of B. binotatus with another research. The result of sequence analysis showed that B. binotatus from Central Java were not significantly different from B. binotatus from East Java, and B. binotatus from West Java were significantly different from two others. The genetic differences of B. binotatus from three locations were observed in five basepair (335 bp, 399 bp,449 bp, 497 bp, and 545 bp). The result of population structure analysis showed an FST value of 1.00. It suggested that there was genetic differentiation between populations of Pasuruan, Yogyakarta and Cirebon. Inter-location analysis requires to be done to confirm the genetic differences from another regions.

Ikan kembung perempuan merupakan ikan ekonomis penting bagi masyarakat peisir. Ikan kembung perempuan masuk dalam red-list species berdasarkan IUCN tahun 2017 sehingga pemanfaatan spesies ini harus diperhatikan. Pemanfaatan secara berlebih dan terus menerus menyebabkan spesies ini semakin berkurang. Hasil tangkapan nelayan yang beragam ukuran dan belum diketahui tingkat kematangan gonad dari ikan tersebut mengakibatkan ikan kembung perempuan menjadi semakin sedikit dan dikhawatirkan akan semakin sulit ditemukan diperairan. Penelitian mengenai tingkat kematang gonad perlu dilakukan untuk mengetahui apakah ikan hasil tangkapan tersebut memang sudah layak untuk ditangkap atau belum layak tangkap (dalam hal ini telah mengalami matang gonad). Hasil penelitian menunjukan Rastrelliger brachysoma mengalami matang gonad pertmakali (Length at first mature) pada panjang 17,03 cm dengan nisbah kelamin 238 ± 20,074 untuk ikan betina dan jumlah 179 ± 25,408 untuk ikan jantan. Hasil analisis menunjukan Rastrelliger brachysoma di Perairan Lekok, Pasuruan mengalami pemijahan pada bulan Oktober-Desember dengan pemijahan tertinggi pada bulan Desember. Analisis histologi menunjukan Rastrelliger brachysoma berada pada tingkat kematangan gonad I, II, III, IV dan V sedangkan analisis morfologi menunjukan Rastrelliger brachysoma berada pada tingkat kematangan gonad I, II, III dan IV.

Barbodes binotatus is a group of freshwater fish and this species is an endemic and most dominant category of freshwater species in Indonesia. Morphological examinations at the level of intraspecific populations by involving extensive sampling localities have never been conducted before. Morphological characteristics through truss morphometry analysis of body shape can be used to analyze shape changes during growth, discriminate genera or species as well as identify good quality of population for fish broodstock. This aims of research were to determine the relationship between fluctuating asymmetry and morphological character of B. binotatus across different regions from Java. A total of 650 samples were analyzed and collected from a total of 24 sampling sites around Java Island. Individual specimens for each population were analyzed using thin plate spline (tpsDig) method with a total of 14 anatomical landmarks. The result of this research inform that PCA analysis showed highly significant different of each population. Research with genetic approach is needed to determine population groupings across distribution area.

Morphological variability-based truss morphometry analysis is often used to identify fish population, morphometric asymmetry, and evolutionary changes of fishes. This study aims to analyze the level of symmetry and asymmetry of Barbodes binotatus from several sampling areas in terms of geographic distribution variability in Indonesia, such as Java, Bali, Nusa Tenggara, Sumatera, Kalimantan and Sulawesi. A total of 845 samples were collected from 28 sampling areas. Digital imaging and landmark points were analyzed using the tpsDig.2 program. The parameters including standard landmarks, truss morphometry and geometric-morphometric analysis were completed using SAGE software in order to identify the symmetry-asymmetry level of fishes from each location. Results showed a highly asymmetry level (P<0.0001) in procrustes ANOVA with three factors analyzed: Individual analysis, side identification, and interactions of individual and side. The asymmetry levels of B. binotatus were varied within areas, which recorded at 65.31% for Java Island, 50.16% for Nusa Tenggara, 67.12% for Bali, 67.12% for Sumatera, 30.15% for Kalimantan, and 30.17% for Sulawesi. The asymmetry level of B. binotatus in four major regions (Java, Nusa Tenggara, Bali, and Sumatra) was significantly higher (P<0.0001), while other areas in Kalimantan and Sulawesi tend to be lower than others (P>0.0001). Further research with a genetic approach is needed to identify genetic populations and prove the existence of genetic factors that affect the level of asymmetry in individual body shape.