Rahardjo, MF
Research Center for Biology-Indonesian Institute of Sciences

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PENGARUH PADAT TEBAR IKAN KOAN {Ctenopharyngodon idella) TERHADAP LAJU PERAMBAHAN DAN LUAS TUTUPAN ECENG GONDOK (Eichornia crassipes) DI DANAU LIMBOTO, GORONTALO

BERITA BIOLOGI Vol 10, No 3 (2010)
Publisher : Research Center for Biology-Indonesian Institute of Sciences

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Abstract

Water hyacinth {Eichhornia crassipes) in Lake Limboto was covering the area about 40 to 60% in 2008. It caused a lot of problems on water transportation, fishing activities, reducing water quantity and quality. To manage the number of water hyacinth population, biological control use omnivorous species and such as grasss carp (Ctenopharingodon idella) is a promosing alternative. In this study, effect of different stocking density of grass carp on the population of water hyacinth was observed. The result showed that 200 fish was the most effective compare to other stocking density and enabled to reducing the covering area up to 10 to 20%.

Small Islands and Coral Reef Ichthyofaunas as the Basic Data for the Fisheries Resource Management

Jurnal Iktiologi Indonesia Vol 19, No 1 (2019): February 2019
Publisher : Masyarakat Iktiologi Indonesia (MII )

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Abstract

Indonesia is one of the biggest archipelago country in the world, These islands lined up, stretching from Sabang to Merauke.  Some government institutions studied the number of islands in Indonesia. In March 2nd 2017 President of Republic Indonesia issued Keppres No. 6 2017 about 111 numbers of outer islands. Two of the islands belongs to Bengkulu Province, i.e Enggano and Mega islands. Stretching in an east-west direction embracing nearly 18,000 islands, the Indonesian Archipelago features a seemingly endless array of marine habitats. The country is the global leader with regards to area occupied by coral reef, estimated at 51,090 km2. The total number of coral reef fishes around 2600 species. The highest diversity of coral reef fishes with about 1766 species is Papua Barat. The dominant family is Gobiidae with 405 species, Labridae about 200 species and Pomacentridae with about 176 species. The islands in Indonesia have a unique history and inhabit by numbers of endemic fish species, i.e Muna island, Aru islands, and Enggano island. LIPI conducted an expedition in Enggano in 2015, the result indicated some undescribed species there. The new species found in Indonesia since a long time ago, started on 16 century up to now. The research on freshwater fish in Indonesia found 66 new fish species. Until now there are still a lot of unexplore waters in Indonesia, and there are still awaiting undescribe fish species to be named. Fish conservation in the small islands need to be done, as most of them migrate to the sea. Some aphidromous species growth and reproduction in freshwaters but the juvenile migrate downstream towards the sea, spreading at sea, metamorphosis phase they enter upstream migration and settlement in the freshwater.AbstrakIndonesia merupakan negara kepulauan yang terbesar di dunia, pulau-pulau ini berjajar, membentang dari Sabang sampai Merauke. Kajian jumlah pulau di Indonesia telah diteliti oleh beberapa lembaga di negeri ini. Sebagai negara kepulauan, Indonesia seolah-olah merupakan habitat laut yang tak berujung. Terumbu karang negeri ini sekitar 51.090 km2 merupakan yang terluas di dunia. Jumlah total spesies ikan di perairan terumbu karang Indonesia sekitar 2600 spesies. Wilayah tertinggi keragaman jenisnya adalah perairan Papua Barat dengan 1766 spesies. Famili yang terbesar adalah Gobiidae 405 spesies, selanjutnya Labridae 200 species dan Pomacentridae 176 spesies. Banyak pulau mempunyai riwayat unik dan dihuni oleh spesies-spesies endemik, diantaranya Pulau Muna, Pulau di Kepulauan Aru, juga Pulau Enggano. Hasil penelitian LIPI di P. Enggano mengindikasikan adanya beberapa jenis baru ikan. Penemuan spesies baru telah berlangsung lama, sejak penelitian iktiofauna di Indonesia dimulai pada abad 16 sampai saat ini. Hasil penelitian ikan air tawar di perairan Indonesia telah mendapatkan 66 spesies baru, sampai saat ini masih banyak wilayah perairan  belum diteliti dan kemungkinan besar ada spesies baru yang menanti diungkap keberadaannya. Konservasi spesies ikan di pulau-pulau kecil perlu dilakukan, mengingat banyak diantara-nya yang beruaya ke laut. Beberapa spesies gobiid bersifat amfidromus, memijah dan menetas di perairan tawar namun anakannya bermigrasi ke laut, mengalami metamorphosis dan kembali lagi ke perairan tawar.

Reproductive biology of silurid catfishes Ompok miostoma (Vaillant 1902) in Mahakam River East Kalimantan

Jurnal Iktiologi Indonesia Vol 19, No 1 (2019): February 2019
Publisher : Masyarakat Iktiologi Indonesia (MII )

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Abstract

Reproductive biology of silurid catfish O.miostoma(Vaillant 1902)as one of endemic species in Mahakam River East Kalimantan is not yet known. This study aimed to analysisreproductive aspect related to changing seasons, including sex-ratio, spawning season, spawning location, length at first gonad maturity, gonado-somatic index, and fecundity. Total fish samples (n=1214)were collected monthly from November 2013 to October 2014 at four locations in the Mahakam River, using many fishing gears.The results of this research showthe total length of fish ranged from 132.19 to 227.30 mm and weight ranged from 20.00 to 70.40 g. The overall sex ratio of male and female was1: 1.56, while at gonad maturity stages were1:1.77. The spawning season range from November to January and peak spawning occurs in December. The highest spawning location was found at swamp flood Semayang Lake. The length at first gonad maturity of male ranged of 191.05-202.60 mm, while it was in 179.56-198.50 female. Maximum average gonado-somatic index (GSI) values obtained for male and female were 0.32 and 2.07 respectively during spawning period in November and declined to minimum in February. The total fecundity and eggs diameter rangedfrom 2648 to 12495 eggsind-1and 0.61 to 1.30 mm respectively. There was a positive correlation between fecundity andtotal length and weightof fishes.AbstrakBiologi reproduksi ikan lais O. miostoma (Vaillant 1902)sebagai salah satu spesies endemik di Sungai Mahakam Kalimantan Timur belum pernah diketahui. Tujuan penelitian ini adalah menganalisisaspek reproduksi ikan laisberkaitan dengan perubahan musimyang mencakupnisbah kelamin, musim pemijahan, lokasi pemijahan, ukuran kali pertama matang gonad, indeks kematangan gonad dan fekunditas.Total ikan contoh 1214 ekor telah dikumpulkan setiap bulan mulai dari bulan November 2013 sampai Oktober 2014di empat lokasi perairan Sungai Mahakam, menggunakan berbagai alat tangkap. Hasil penelitian menunjukkanukuran panjang total ikan berkisar dari 132,19-227,30 mm dan bobot berkisar dari  20,00-70,40 gram.Nisbah kelamin seluruh ikan jantan dan betina yang diamati 1 : 1,56, sedangkanpada tahap kematangan gonad 1:1,77. Musim pemijahan terjadi mulai dari bulan November sampai Januari dan puncak pemijahan pada bulan Desember. Lokasi pemijahan tertinggi ditemukan di rawa banjiran Danau Semayang. Ukuran ikan pertamamatang gonad pada jantan berkisar dari 191,05-202,60 mm dan betina berkisar dari 179,56-198,50 mm. Rata-rata indeks kematangan gonad (IKG)  tertinggi ditemukan pada jantan dan  betina berturut turut 0,32  dan 2,07 selama musim pemijahanpada bulan November dan menurun hingga terendah pada bulan Februari. Fekunditas total berkisar dari 2.648-12.495 butir telur per individu.Ada korelasi positif antara fekunditas dengan panjang total dan bobot ikan.