Milkfish is one of the important economical fish species that usually lives and cultivated in estuarine areas. However, milkfish can adapt to habitat with salinity ranging from 0 - 40 ppt. Therefore, milkfish is a potential choice of introduced fish in freshwaters. This study aims to determine the survival rate and growth rate of milkfish seed in the waters of Ir. H. Djuanda Reservoir. H. Djuanda. The study was conducted experimentally in November – December 2017, every week for five weeks in floating net cages with a size of 7 x 3 m and depth 0.75 m at Ir. H. Djuanda Reservoir with three treatments of densities that are 4,000; 6,000 and 10,000 seeds. The size of milkfish seeds used was 3-5 cm because it was able to adapt in freshwaters. The milkfish was cultivated by the extensive system without a commercial feed so they only use natural food. The results showed that the number of dead milkfish increased with increasing density and the highest mortality occurred on the day 7th in 10,000 density treatment. The milkfish seed mortality began to decrease on the day 9th of the trial and the deaths did not occur again on the day 19th-21st. The highest survival rate was 79.21% for 6,000 densities. The highest length growth rate was 0.93 mm/day for 6,000 densities. The smallest estimated investment was 10,000 densities, but it has the largest losses due to seed death. Because the condition was dense, there was competition for food, oxygen, and space. Therefore, seed acclimation is carried out in stages.

The eutrophication in Jatiluhur Reservoir had continued due to organic pollution. The high eutrophication negatively impacted reservoir sustainability and some activities there, such as fisheries. This study aimed to determine the level of eutrophication and provide some alternative recommendations for its control. The research was conducted by sampling method in 2017 on nine representing stations. A stratified sampling method took samples of water and phytoplankton. The results showed that based on the TSI index value (>4), Trix index (>50), the eutrophication status of the Jatiluhur reservoir was in eutrophic-hypertrophic level. Some alternative control which could recommend were: (1) utilizing macrophyte as a nutrient absorbing agent, (2) stocking of planktivorous fish, and (3) implementing an environmental friendly of fish culture in floating cage system.

Ikan bilih (Mystacoleucus padangensis) merupakan ikan endemik dan mempunyai nilai ekonomi penting di Danau Singkarak. Ekploitasi berlebih dengan menggunakan alat tangkap yang tidak selektif telah menyebabkan penurunan populasi. Hal ini berdampak pada penurunan pendapatan nelayan sehingga perlu suatu upaya konservasi yang dapat dilakukan dengan penentapan ukuran tangkap serta penetapan suaka. Penulisan ini bertujuan untuk menentukan ukuran layak tangkap dan penetapan suaka alahan sebagai upaya konservasi ikan bilih di Danau Singkarak. Penelitian dilakukan pada bulan Juli dan September 2019 pada dua lokasi yaitu Aripan dan Sumpur. Contoh ikan bilih diperoleh dengan percobaan penangkapan menggunakan jaring insang dengan ukuran mata jaring 5/8; ¾ dan 1,0 inci; jala, serta Alahan. Hasil penelitian menunjukkan bahwa ikan Bilih boleh dieksploitasi pada ukuran ≥ 9,0 cm dengan menggunakan jaring insang ukuran mata jaring 1,0 inci. Penetapan alahan di Sungai Sumpur sebagai suaka akan memberikan benih ikan bilih sebanyak 1,29 juta ekor dengan ikan dewasa yang layak tangkap dan siap memijah sebanyak 182 ribu ekor. Penetapan ukuran layak tangkap serta suaka alahan memberikan dampak pada keberlanjutan sumberdaya ikan serta peningkatan pendapatan nelayan di Danau Singkarak.

Floating net cages culture (FCC) activity is growing rapidly and becoming one of the largest national freshwater fish producers. Most of the lake/reservoir in Indonesia has been utilized for aquaculture in the FCC system. The positive impact of the FCC includes opening up employment opportunities and increasing the income of farmers and labourers leading to the economic improvement of local community. However, there are negative impacts caused by uneaten feed such as water quality degradation, blooming of macrophytes and algae, hydropower turbine damage due to corrosion, a decreased in the abundance of fish species and others. For this reason, environmentally friendly FCC might offer a solution to control or reduce the release of uneaten feed. One of these technologies is SMART FCC that integrates fish culture and hydroponic or called aquaponics systems applied in open waters of reservoirs/lakes. The main advantage of SMART FCC is its ability to reduce FCC waste because the uneaten feed is not dispersed into the waters, rather it is collected and settles in SMART FCC. The deposited wasted feed can be used as liquid organic fertilizer for the hydroponic plants. At the end, the fish farmers get not only harvested fish but also gain additional benefits and profits from organic plant production.

Salah satu kriteria penting untuk menentukan suatu lokasi menjadi suaka perikanan agar dapat berfungsi sebagai sumber benih untuk meningkatkan produksi ikan adalah ketersediaan pakan alami seperti plantkon. Tujuan dari penelitian ini untuk mengetahui komposisi, keanekaragaman, dan dominansi fitoplankton sebagai pakan alami ikan pada perairan calon suaka perikanan di Waduk Koto Panjang, Riau. Contoh diambil pada lima stasiun pengamatan pada bulan Maret, Juni, dan Desember 2007. Parameter yang dianalisis adalah komposisi dan kelimpahan, keanekaragaman, serta dominansi fitoplankton. Hasil pengamatan menunjukkan bahwa di Waduk Koto Panjang, Riau ditemukan lima kelas fitoplankton yaitu Chlorophyceae (21 marga), Cyanophyceae (tiga marga), Bacillariophyceae (tujuh marga), Dinophyceae (tiga marga), dan Euglenophyceae (dua marga) dengan total kelimpahan fitoplankton 6,6x105 ind. per L. Total nilai Indeks Keanekaragaman selama pengamatan adalah 2,97, berarti bahwa kondisi lingkungan di Waduk Koto Panjang sangat baik dan tidak tercemar. Terdapat tiga marga fitoplankton yang mendominansi yaitu Cosmarium, Staurastrum, dan Peridinium dengan nilai dominansi kumulatif masing-masing sebesar 26,54: 23,92; dan 13,37%. One important criteria for selecting a site to be inland fishery reserve to increase fish seed production is the availability of natural food such as plankton.The objective of this study was to elucidate the composition, diversity, and dominancy of phytoplankton as natural food of fish in proposed site of inland fishery reserve of Koto Panjang Reservoir. The phytoplankton sample was taken in five stations at March, June, and December 2007. The Koto Panjang Reservoir had five classes of phytoplankton, namely Chlorophyceae (21 genus), Cyanophyceae (three genus), Bacillariophyceae (seven genus), Dinophyceae (three genus), and Euglenophyceae (two genus) with the total abundance of 6,6x105 ind. per L. Total index of diversity of phytoplankton was 2.97, meaning that the Koto Panjang Reservoir was still in a good condition and unpolluted yet. There were three genera of phytoplankton dominating in the Koto Panjang Reservoir, namely Cosmarium, Staurastrum, and Peridinium at a respective dominancy cumulative index value of 26.54%; 23.93; and 13.37.