Catfish is a species of freshwater fish that contains a source of protein and it has economic value and has become one of the famous commodities in Indonesia. Biofloc can be one alternative waste fixers intensive cultivation for reduce the waste of inorganic nitrogen and also provide additional protein for increase growth and feed efficiency. This study was to determine the effect of high stocking densities on the growth performance of african catfish in biofloc system. This study used completely randomized design (CRD) with different stocking densities in the system biofloc T1.(1000/m3), T2.(1500/m3), T3.(2000/m3), and T4.(2500/m3). Animal trials were using jouvenile african catfish with an average weight of 1.06±0.3g, which maintained in a pool tarpoulin cage with water volume ±2000L for 50 days with feeding ratio 3% of the weight biomass. The results showed a significantly different effect (P<0.05) against the value of hepatosomatic index, absolute growth and daily growth rate, but the result not significant at spesific growth rate. The second treatment (T2) showed the best results than others in the growth rate and daily growth rate with a value of 6.45±3.1g for absolute growth and 0.13±0.06g for daily growth rate. The four treatment showed the best results than others in the hepatosomatic index with value 4.7 ± 1.8%. These findings demonstrate a role of biofloc technology in catfish aquaculture.

Ikan-ikan dari Famili Bagridae di Indonesia mencapai 60 jenis dan salah satunya dari genus Msytus. Metode yang digunakan untuk identifikasi ikan yang sangat cepat dan akurat sangat diperlukan. DNA barcoding adalah teknik identifikasi baru dengan pendekatan molekular. Gen CO1 diamplifikasi dan produk PCR disekuensing serta dianalisis dengan menggunakan software bioinformatika. Pengeditan hasil sekuensing dan penentuan komposisi nukleotida dianalisis dengan software Mega5. Urutan DNA disejajarkan dengan ClustalW vers. 1.4. Sekuens dibandingkan dengan data GenBank menggunakan BLAST (Basic Local Aligment Search Tools) dan BOLDSystems. Pohon filogenetik dibuat dengan menggunakan metode Neighbor_Joining. Salah satu contoh identifikasi ikan dari genus Mystus yang telah dikonfirmasi adalah Mystus nigriceps menjadi Mystus singaringan.

This study was aimed to analyze the growth performance of African catfish Clarias gariepinus cultured in the biofloc system at high stocking density. African catfish with an average weight of 1.85±0.09 g were cultured in four units of tarpaulin tank at a diameter of 1.72 m and a height of 1.05 m with a volume of ±2,000 L at the different density of 1,000 fish/m 3 ; 1,500 fish/m 3 ; 2,000 fish/m 3 ; 2,500 fish/m 3 . During rearing period, fish were given the artificial feed with protein contents of 28.75% with the frequency of twice a day, as much as 3% of the body weight. The results showed that different treatment of high stocking density in the biofloc system had a significant effect on the absolute growth rate, lipid retention and energy retention (P<0.05) but not significant effect on daily growth rate. The results showed that the highest lipid retention and energy retention were found in the group of fish treated at a stocking density of 2,500 fish/m 3 but declining protein retention and growth in fish occurred. The highest absolute growth rate and daily growth rate were shown by treatment with a stocking density of 1,500 fish/m 3 .Keywords: growth, stocking density, biofloc ABSTRAKPenelitian ini bertujuan untuk menganalisis performa pertumbuhan ikan lele dumbo Clarias gariepinus yang dipelihara pada sistem bioflok dengan padat penebaran tinggi. Ikan uji memiliki berat rata-rata 1,85±0,09 g yang dipelihara pada kolam terpolin berdiameter 1,72 m dan tinggi 1,05 m dengan volume air ±2.000 L sebanyak empat unit dengan kepadatan yang berbeda yaitu 1.000 ekor/m 3 , 1.500 ekor/m 3 , 2.000 ekor/m 3 , 2.500 ekor/m 3 . Selama 40 hari masa pemeliharaan, ikan diberi pakan buatan berkadar protein 28,75% dengan frekwensi dua kali sehari, sebanyak 3% dari berat tubuh. Hasil penelitian menunjukkan bahwa perlakuan perbedaan padat penebaran tinggi pada sistem bioflok memberikan pengaruh yang nyata terhadap pertumbuhan mutlak, retensi lemak dan retensi energi (P<0,05) namun tidak memberikan pengaruh nyata terhadap laju pertmbuhan harian. Hasil penelitian menunjukkan bahwa semakin tinggi padat penebaran terjadinya peningkatan retensi lemak dan retensi energi yaitu pada perlakuan padat penebaran 2.500 ekor/m 3 tetapi terjadi penurunan nilai retensi protein dan pertumbuhan pada ikan. Nilai pertumbuhan mutlak tertinggi ditunjukkan oleh perlakuan dengan padat penebaran 1.500 ekor/m 3 .

Masalah utama yang dihadapi oleh para pembudi daya ikan lele dumbo saat ini adalah inefisiensi input produksi yaitu pemanfaatan pakan. Produktivitas dan margin keuntungan yang dihasilkannya sangat rendah. Permasalahan lain dari inefisiensi pakan yang muncul yaitu sisa pakan di dasar kolam dan pada akhirnya dapat menyebabkan racun bahkan Kematian pada ikan dan kegagalan produksi. Salah satu upaya yang perlu dilakukan adalah merekayasa dengan teknologi bioflok. Teknologi Bioflok pada budi daya ikan lele sangat penting ditransfer kepada masyarakat pembudi daya ikan. Tujuan kegiatan ini adalah untuk meningkatkan pengetahuan, keterampilan dan pendapatan masyarakat pembudi daya ikan. Metode yang dilakukan yaitu dengan alih teknologi, demonstrasi plot dan penerapan IPTEK. Hasil menunjukkan dengan masyarakat pembudi daya antusias dan terampil dalam penguasaan teknologi bioflok. Produktivitasnya mencapai 568 Kg dengan kepadatan tinggi dan FCR mencapai 0,7 serta keuntungan bersih mencapai Rp. 2.850.000,-. Kata kunci: lele, bioflok, teknologi

The status and potential of ichtyofauna resources in freshwaters, especially downstream of the river, must be monitored and evaluated frequently. Land use along the downstream river is often used as mining and industrial activities. The purpose of this study was to find out ichtyofauna in down stream of the Klawing Purbalingga River in Central Java. The study was conducted in January-March 2017 with descriptive exploratory method. Sampling using gill nets with the help of local fishermen. The fish obtained were identified and grouped by family to the species level. The results showed that in the down stream of the Klawing River there were species diversity consisting of 13 species, 7 families and 13 genera. Ichtyofauna from Cyprinidae family dominate as many as 6 species followed by Bagridae family 2 species. One introduced species of Osphronemus gouramy and one invasive alien fish species Hypostomus plecostomus and other species were indigenous species.

This study was aimed to analyze the growth performance of African catfish Clarias gariepinus cultured in the biofloc system at high stocking density. African catfish with an average weight of 1.85±0.09 g were cultured in four units of tarpaulin tank at a diameter of 1.72 m and a height of 1.05 m with a volume of ±2,000 L at the different density of 1,000 fish/m 3 ; 1,500 fish/m 3 ; 2,000 fish/m 3 ; 2,500 fish/m 3 . During rearing period, fish were given the artificial feed with protein contents of 28.75% with the frequency of twice a day, as much as 3% of the body weight. The results showed that different treatment of high stocking density in the biofloc system had a significant effect on the absolute growth rate, lipid retention and energy retention (P<0.05) but not significant effect on daily growth rate. The results showed that the highest lipid retention and energy retention were found in the group of fish treated at a stocking density of 2,500 fish/m 3 but declining protein retention and growth in fish occurred. The highest absolute growth rate and daily growth rate were shown by treatment with a stocking density of 1,500 fish/m 3 .Keywords: growth, stocking density, biofloc ABSTRAKPenelitian ini bertujuan untuk menganalisis performa pertumbuhan ikan lele dumbo Clarias gariepinus yang dipelihara pada sistem bioflok dengan padat penebaran tinggi. Ikan uji memiliki berat rata-rata 1,85±0,09 g yang dipelihara pada kolam terpolin berdiameter 1,72 m dan tinggi 1,05 m dengan volume air ±2.000 L sebanyak empat unit dengan kepadatan yang berbeda yaitu 1.000 ekor/m 3 , 1.500 ekor/m 3 , 2.000 ekor/m 3 , 2.500 ekor/m 3 . Selama 40 hari masa pemeliharaan, ikan diberi pakan buatan berkadar protein 28,75% dengan frekwensi dua kali sehari, sebanyak 3% dari berat tubuh. Hasil penelitian menunjukkan bahwa perlakuan perbedaan padat penebaran tinggi pada sistem bioflok memberikan pengaruh yang nyata terhadap pertumbuhan mutlak, retensi lemak dan retensi energi (P<0,05) namun tidak memberikan pengaruh nyata terhadap laju pertmbuhan harian. Hasil penelitian menunjukkan bahwa semakin tinggi padat penebaran terjadinya peningkatan retensi lemak dan retensi energi yaitu pada perlakuan padat penebaran 2.500 ekor/m 3 tetapi terjadi penurunan nilai retensi protein dan pertumbuhan pada ikan. Nilai pertumbuhan mutlak tertinggi ditunjukkan oleh perlakuan dengan padat penebaran 1.500 ekor/m 3 .

This study aims to find out the status and management of Senggaringan fish as resources in the Klawing River, Purbalingga District, Central Java, Indonesia. Research method employed was in-depth interview method using open questionnaires related to the use of aquatic and fish resources. The results have showed that there was a conflict of interest in the utilization and management of the Klawing River by various parties including farmers, fishermen, industry, and local/central government. Conflicts of interests that are not managed properly are a threat to existing aquatic ecosystems and fish resources. Senggaringan fish has potential of benefits for the surrounding community, both for the economic benefit and nutrients benefit. However, senggaringan fish are often exploited by unsustainable and environmentally unfriendly consumption. Various activities on the Klawing River are thought to cause water conditions and the senggaringan fish population to deteriorate. Considering the status and the potential of senggaringan fish, various co-management efforts, monitoring water quality, fishing method at regular intervals, restocking, and domestication need to be done.

<p class="BasicParagraph" align="center"><strong>ABSTRACT</strong></p><p class="BasicParagraph" align="center"><strong> </strong></p><p class="Pa2">The objective of the research was to evaluate nutritional values of microencapsulated diet made from single cell protein of microalgae. Complete randomized design was applied using three different types of microalgae for inclusion trials i.e. (A) <em>Nannochloropsis </em>sp., (B) <em>Chlorella </em>sp., and (C) <em>Spirulina </em>sp. with five replications respectively. Microencapsulated diet was produced by a modification method based on thermal cross-linking with stable temperature. Phytoplankton was cultured in sea water for which fertilized by a modification of Walne and Guillard fertilizer. The results showed that the highest value of nutrition content was <em>Spirulina </em>sp. and the average composition of protein, crude lipid, carbohydrate, ash, nitrogen free extract, and water content was 34.80%, 0.30%, 18.53%, 20.09%, 26.29%, and 13.32%, respectively. Organoleptically, microcapsule showed that the color of capsule was dark green and smell fresh phytoplankton.</p><p class="Default"> </p>Keywords: microcapsule, single-cell protein, thermal cross-linking, microalgae, phytoplankton<br /><p class="BasicParagraph"> </p><p class="BasicParagraph"> </p><p class="BasicParagraph" align="center"><strong>ABSTRAK</strong></p><p class="BasicParagraph"><strong> </strong></p><p class="Pa2">Tujuan penelitian adalah mengevaluasi kandungan nutrisi pakan mikrokapsul protein sel tunggal (<em>single cell protein</em>) yang berasal dari berbagai jenis mikroalga (fitoplankton). Rancangan percobaan yang digunakan adalah rancangan acak lengkap, dengan perlakuan inklusi mikrokapsul dari jenis fitoplankton (A) <em>Nannochloropsis </em>sp., (B) <em>Chlorella </em>sp., dan (C) <em>Spirulina </em>sp., masing-masing diulang lima kali. Pembuatan mikrokapsul dilakukan dengan menggunakan modifikasi metode dasar <em>thermal cross-linking</em>, serta menerapkan teknik pengeringan suhu konstan. Proses pembuatan mikrokapsul protein diawali dengan kultur fitoplankton jenis <em>Nannochloropsis </em>sp., <em>Chlorella </em>sp., dan <em>Spirulina </em>sp. Kultur dilakukan di dalam laboratorium menggunakan media air laut dan modifikasi pupuk Walne dan Guillard. Hasil penelitian menunjukkan bahwa kandungan nutrisi tertinggi terdapat pada jenis mikrokapsul protein sel tunggal yang berasal dari <em>Spirulina </em>sp., dengan rata-rata komposisi kandungan protein 34,80%, lemak 0,30%, karbohidrat 18,53%, abu 20,09%, dan BETN 26,29%. Mikrokapsul berwarna hijau tua dan aroma fitoplankton segar.</p><p class="Default"> </p>Kata kunci: mikrokapsul, protein sel tunggal, <em>thermal cross-linking</em>, mikroalga, fitoplankton