GENETIC DIVERSITY EEL Anguilla marmorata BY RAPD IN THUA THIEN HUE PROVINCE, VIETNAM

Anguilla marmorata is a species with high economic value and increasingly interested by organizations and scientists. So far, many of the eel's biological characteristics remain mysterious, and they are often classified according to morphological features such as pigmentation patches, number of vertebrae, ... It is even difficult to distinguish one individual from another in some species, especially in the larval stage. In this study, the Random amplification of polymorphic DNA (RAPD) molecular marker was used to evaluate the genetic diversity of 48 eels collected in Thua Thien Hue province. Results showed that the genetic diversity of individuals in the Eel population studied is quite high. With 8 random primers via PCR, 77 DNA tapes with 76 polymorphic tapes were obtained, the tape size ranged from 170-2,500 bp, in which primer S10 showed the highest diversity with an average Ho value of 0.563, followed by primer S8 (Ho = 0.558). The lowest diversity was in the OPD5 primer (Ho = 0.300). The OPG17 primer is the primer that produces the most polymorphic tapes (13/13 tapes) and the S3 primer for the least amplified tapes polymorphism (9/10 DNA tapes). The diversity coefficient in each random primer ranged from about 0.300 to 0.563, with an average of 0.433. The genetic variation in the Eel population is random. Genetic variation can be attributed mainly to different eel breeding conditions and origins. Genetic similarity coefficients among the Eels varied from 0.660 to 0.910 and were divided into two main groups in genetic similarity coefficient 0.660.

KERAGAMAN IKAN SIDAT (Anguilla sp.) FASE BENIH DAN DEWASA DI SUNGAI DUMOGA, SULAWESI UTARA

Sungai Dumoga di Sulawesi Utara memiliki potensi benih sidat yang melimpah karena dekat dengan lokasi pemijahan. Lokasi pemijahan Anguilla borneensis dan Anguilla celebesensis berada di laut lepas Sulawesi dan Teluk Tomini. Lokasi pemijahan Anguilla marmorata dan Anguilla bicolor pacifica berada di bagian barat Pasifik Utara. Kegiatan ini bertujuan untuk memberikan informasi penting bagi langkah penelitian ikan sidat di Indonesia sehingga dapat berkontribusi untuk pengembangan strategi pengelolaannya. Spesies sidat diperoleh di muara Sungai Dumoga terdiri dari A. marmorata sebanyak 1.106 ekor, A. bic. pacifica sebanyak 854 ekor dan Anguilla spp sebanyak 291 ekor. Nilai anodorsal terbagi dalam tiga kelompok yaitu ±15,57% (A. marmorata); ±1,18% (A. bicolor pacifica) dan ±7,09% (Anguilla spp.). Nilai meristik A. marmorata untuk Tulang Belakang (TB) total 104-106 buah, pre-dorsal TB 17-19 buah, pre-anal TB 36-39 buah dan ano-dorsal TB 18-20 buah. Nilai meristik A. bicolor pacifica untuk tulang belakang (TB) total 108-112 buah, pre-dorsal TB 32-36 buah, pre-anal TB 32-39 buah dan ano-dorsal TB 0-3 buah. Nilai meristik Anguilla spp untuk tulang belakang (TB) total 100-106 buah, pre-dorsal TB 27-29 buah, pre-anal TB 30-33 buah dan ano-dorsal TB 6-12 buah. Pola pertumbuhan sidat dewasa bersifat allometrik negatif, yakni pertambahan panjang tubuh lebih cepat dibandingkan dengan pertambahan berat tubuh yang lebih lambat. Kondisi sidat dewasa di Sungai Dumoga tidak gemuk karena faktor kondisinya berkisar antara 0,0024-0,0036. Panjang rata-rata sidat dewasa 58.92cm pada Anguilla marmorata (IKG 1,57–2,90%); 54,2cm pada A. bicolor pacifica (IKG 1,27–2,79%) dan 52,32cm pada Anguilla spp (IKG 0,97-2,50%).

Influence of environmental parameters on habitat use by sympatric freshwater eels, Anguilla marmorata and A. japonica on Yakushima Island, Japan

It is known that environmental parameters, such as water depth, size of substrate material, and current velocity influence the organization of stream fish communities. However, few studies have investigated the effects of these parameters on sympatric freshwater eels. Here, the habitat use of two anguillid eels, Anguilla marmorata Quoy and Gaimard, 1824 and A. japonica Temminck and Schlegel, 1846, coexisting in the same river systems in Japan was investigated. It was found that the tropical species A. marmorata exclusively utilized habitats with larger substrate materials, fewer fallen leaves and less leaf detritus, higher current velocity, and lower turbidity than the temperate species A. japonica, and the distributions of the two anguillid eels were clearly segregated. Thus, when both species co-occur in the same river systems, clear flowing mainstems and tributaries are preferred habitats for A. marmorata, while stagnant muddy estuaries, backwater areas, irrigation channels, and reservoirs are preferred habitats for A. japonica. These habitat segregations were consistent through body-size increases and life-stage developments from elver to yellow eel and did not show ontogenetic shifts. The findings indicated that both species had strong habitat preferences, and these environmental parameters must be considered in the conservation of anguillid eels in sympatric zones.

Species of Fish in rivers in the Northern Peninsula of Sulawesi Island

This study aims to determine the species of fish found in the Poigar River, Ranoyapo River, Maruasey River, Talawaan River, and Likupang River in the northern peninsula of Sulawesi Island. These five rivers empty into the Sulawesi Sea. Sampling was carried out in the upstream, middle and downstream parts of the river, all sampling areas were freshwater areas, estuary areas with brackish water types were not included in this study. Sampling was carried out using cast nets and electric shocks. There are 58 species (16 orders, 21 families, 40 genera). Families Gobidae (9 genera, 19 species) and Eleotridae (8 genera 13 species), 19 other families have only 3 or 2 or 1 species. There are 28 species of Ranoyapo River, 25 species of Maruasey River, 23 species of Poigar River, 15 species of Likupang River, and 9 species of Talawaan River. Eel Anguilla marmorata widely distributed in five rivers, and Eleotris melanosoma (Eleotridae) Osteochilus hasseltii (Cyprinidae) in four rivers. The other species are only found in 3, 2, and 1 rivers. There are 27 species found in only one river.Keywords: Freshwater; River; Species; Fish.AbstrakPenelitian ini bertujuan untuk mengetahui spesies ikan yang terdapat di Sungai Poigar, Sungai Ranoyapo, Sungai Maruasey, Sungai Talawaan dan Sungai Likupang di semenanjung utara Pulau Sulawesi. Lima sungai ini bermuara di Laut Sulawesi. Pengambilan sampel dilakukan pada bagian hulu, tengah dan bagian hilir sungai, seluruh wilayah pengambilan sampel adalah wilayah air tawar, daerah muara dengan tipe air payau tidak termasuk dalam penelitian ini. Pengambilan sampel dilakukan dengan menggunakan jaring lempar dan kejutan listrik. Terdapat 58 spesies (16 ordo, 21 famili, 40 genus). Famili Gobidae (9 genus, 19 spesiies) dan Eleotridae (8 genus 13 spesies), 19 Famili yang lain hanya memiliki 3 atau 2 atau 1 spesies. Sungai Ranoyapo terdapat 28 spesies, Sungai Maruasey 25 spesies, Sungai Poigar 23 spesies, Sungai Likupang 15 spesies dan Sungai Talawaan 9 spesies. Ikan sidat Anguilla marmorata menyebar luas pada lima sungai, dan Eleotris melanosoma (Eleotridae) Osteochilus hasseltii (Cyprinidae) pada empat sungai. Spesies yang lain hanya ditemukan pada 3, 2 dan 1 sungai. Terdapat 27 spesies yang ditemukan hanya pada satu sungai.Keywords: Freshwater; River; Species; Fish.