Chairulwan Umar’s scientific contributions

Fishing activity in Malahayu Reservoir has been done since long time. Unlimited fishing may impact to the decresing of fish resources of those waters. This study presents an assessment of fishing practices in Malahayu reservoir between 2008-2016 periods. Data of potential fish production and catch per unit effort were estimated by using different estimate models, catch per unit effort was analyzed annually, while potential fish production was analyzed by using five models namely model by Henderson & Welcome (1974), Teows & Griffith (1979), Marshal (1984), Moreau & De Silva (1991) and Crul (1992). The results show that changes of fish composition has accured, which was originally dominated by native fish while for now it is dominated by 72,05% of tilapia (Oreochromis niloticus) as an introduced fish. Furthermore, the average catch per unit effort (CPUE) in Malahayu reservoir is about 11,82 kg / fisherman, while the average potential production is about 198,55 kg / year. CPUE value and potential production indicate that exploitation rate in Malahayu Reservoir are in fully-exploited or perhaps over-exploited condition. Related to those conditions, not to increase the number of efforts (fishermen) as a management option towards sustainable fisheries.

Mass mortality events (MMEs) on fish tend to increase recently both for cultured and wild fish both in coastal and inland waters. The MMEs on wild fish are mostly unknown. Mass mortality events on wild fishes of Mimika estuary, Papua have been recorded since long time ago and limited information was provided due to its remote area. A rapid appraisal study of mass mortality event (MME) of wild fishes chronology and cause was conducted in Yamaima river to Tifuka Estuary, Papua Province a week after the MME in April 2016. Seven sampling sites were selected. Two activities were conducted during the field survey: interview with the local people to get information on the chronology of the MME and collecting primary data on aquatic environment quality and fish samples. The occurance of goldstripe sardine inYamaima river and Tifuka estuary were triggered by the present of strong El Nino with ONI value more than 0.5oC in the ocean and atmosphere above Equator Pasific. Water quality at MME site was similar with remaining schooling fish and Tifuka estuary sites. Concentration of heavy metals in the sediment tend to decreased along with the distance from the MME site. Mass mortality of goldstripe sardinella could relate to oxygen suffocation as a result of disorentation movement of the fish shoals inaccordance with low tide and new moon phase. The number of the death goldstripe sardinella was estimated 200,000 fish with the weight of 18 tons. To mitigate MMEs in the future, efforts should be done such as: routine early detection of El Nino pattern and its effect on salinity and water temperature raising by placing key water quality parameter buoy in the mouth river of Papua and to set net or stack of logs in the cape area of west tailing levee Yamaima river to prevent the entrapment of migrating small pelagic fish specialy in the closed water area.

Ikan bandeng (Chanos chanos) di Waduk Sempor diintroduksi pada tahun 2014 melalui penerapan teknologi perikanan tangkap berbasis budidaya (Culture Based Fisheries, CBF). Penelitian ini bertujuan untuk mengevaluasi pertumbuhan bandeng melalui pengamatan parameter pertumbuhan dan biologi populasinya di Waduk Sempor, Jawa Tengah. Data yang dianalisis diperoleh dari hasil pencatatan enumerator periode September 2014 sampai– Desember 2015. Kajian dinamika populasi ikan bandeng yang meliputi laju pertumbuhan, laju kematian dan tingkat pemanfaatan mengacu pada persamaan Von Bertalanffy dan turunannya. Aspek biologi meliputi hubungan panjang berat mengacu pada model logistik, serta faktor kondisi, keseluruhan analisis dilakukan secara manual dengan program excel 2007. Hasil penelitian menunjukan bahwa parameter pertumbuhan panjang-asimtotik L∞ = 55,97 cm TL dan K= 0,38 per tahun. Laju kematian total (Z) = 1,17 per tahun, kematian alami (M) = 0,56 per tahun, kematian akibat penangkapan (F) = 0,61 per tahun serta laju eksploitasi (E) = 0,5. Pertumbuhan populasi dan laju pemanfaatan menunjukkan bahwa bandeng sudah dimanfaatkan secara optimal oleh masyarakat di sekitar Waduk Sempor. Milkfish (Chanos chanos) was introduced at 2014 in Sempor Reservoir through culture based fisheries (CBF) technology. This study aims to evaluate population growth of the milkfish in Sempor Reservoir. Data were collected from September 2015 to December 2016, and were analyzed using excel 2007 programe manually. Analysis of length-weight relationship is refers to logistic model, population dynamic like growth rate, mortality and mortality rate are refers to Von Bertalanffy and differentiate of it. Biology of population like length-weight relationship are refers to logistic model, and condition factor. The results showed that growth parameters were L∞ = 55.97 cm TL and K = 0.38 year-1. Total mortality (Z) = 1.17 year-1; M = 0.56 year-1; F = 0.61 year-1; and E=0.5. The growth rate and exploitation rate of Milkfish (Chanos chanos) in Sempor Reservoir has been utilized optimally.

Provinsi Nusa Tenggara Timur (NTT) memiliki sekitar 680 buah embung dan bendung berukuran antara 0,5-155 ha, dengan luas total 1.630 ha. Potensi sumber daya perairan tersebut belum dimanfaatkan untuk pengembangan perikanan. Dewasa ini, badan air tersebut hanya berfungsi sebagai penampung air untuk keperluan irigasi pertanian dan minum ternak serta kebutuhan air rumah tangga. Tulisan ini bertujuan untuk merumuskan upaya pengelolaan dan pemanfaatan embung serta bendung yang berbasis budidaya (culture-based fisheries/CBF) di Provinsi Nusa Tenggara Timur. Metodologi pengumpulan data dan informasi dilakukan dengan studi literatur yang dianalisis secara deskriptif. Potensi produksi ikan di embung dan bendung di NTT diperkirakan berkisar antara 34.3-55.8kg/ha/th dengan kondisi kualitas air yang masih baik dan mampu mendukung kehidupan organisme terutama ikan. Beberapa perairan embung dan bendung memiliki tingkat kesuburan sedang (mesotrof) hingga sangat tinggi (hypereutrof) dengan jenis plankton yang mendominasi yaitu kelas Cyanophyceae (genera Anabaena dan Oscilatoria) dan Dynophyceaea (Peridinium). Kelembagaan pengelola sumber daya ikan belum terbentuk, namun kelompok tani yang terlibat dalam pengelolaan badan air dengan struktur organisasi yang jelas sudah ada. Agar kegiatan CBF dapat berjalan dengan baik maka pemerintah daerah harus mengoptimalkan produksi benih di hatchery ikan bandeng dan menyusun regulasi yang mengatur penebaran ikan dan penerapan CBF.In East Nusa Tenggara Province there are 680 small reservoirs and dams (range from 0.5 to 155 ha/unit), with the total waters area of around 1,630 ha. Its high potential resources have not been utilized yet for fisheries. Nowadays, NTT’s dams and reservoirs are only be utilized for agricultural irrigation, livestock and household needs. Culture-based fisheries (CBF) is a technology that is suitable and recommended to be applied and developed in reservoirs or dams, because it does not alter the function ofthe reservoir. This paper aims to formulate cultured based fisheries management and utilization efforts of dams and small reservoirs in East Nusa Tenggara. Desk study was used to collect data and information, and analized and descriptively.The results show that the fish production potential of dams and reservoirs in NTT province was around 34.3-55.8 kg/ha/year. Most of the dams and reservoirs have clear water and able to support aquatic organism particulalrly for fish as the main exploited resources.Productivity levels varied from mesotrof to hypereutrof, inhabited by plankton group dominated by Cyanophyceae (Anabaena dan Oscilatoria) and Dynophyceae (Peridinium). The formal agency responsible to manage the resources was not established yet; however, some groups of fishers who directly utilized the resources have been developed. The local government of NTT should optimally increased the productivity of their owned hatchery to produce milk fish fry and able to arrange the regulation which guides the restocking and CBF implementation.

Kualitas air kolam tadah hujan yang cepat memburuk mengakibatkan penurunan lajupertumbuhan ikan yang dipelihara. Untuk mengatasi hal tersebut, penelitian pemacuanpertumbuhan ikan nila di kolam tadah hujan telah dilakeanakan di Balai Penelitian Perikanan Air Tawar, Sukamandi.

Usaha budi daya ikan di Keramba Jaring Apung (KJA) di perairan umum menunjukkan tendensi penurunan mutu perairan akibat akumulasi sisa hasil metabolisme.

Dalam rangka meningkatkan nilai tambah pada ikan mas, telah dilakukan penelitian mengetahui pengaruh tingkat salinitas terhadap kualitas daging ikan mas. Tingkat salinitas uynatnugk dipakaiadalah 0,6, 8, dan 10 ppt. lkan yang digunakan ukurln 100 g, berasaldari kolam air deras dan keramba jaring apung. Kualitas daging ikin mas ditentukan dengan menggunakan param- eter tekstur daging dan rasa.

Penelitian dilaksanakan pada bulan April sampai Juli 2002 di sekitar dan di luar lokasi budi daya ikan dalam keramba jaring apung (KJA) di Waduk lr. H. Juanda Jatiluhur. Adapun tujuan penelitian ini untuk mengetahui struktur komunitas dan kelimpahan fitoplankton serta mempelajari keterkaitan antara struktur komunitas dan kelimpahan fitoplankton dengan kandungan unsur hara di lokasi KJA dan di luar lokasi KJA.

Pembendungan sungai citarum meniadi waduk k. H. Diuanda, Jatiluhur telah merubah ekosistem perairan mengaril menjadi ekosistem plrairan tergenang. Perubahan tersebut diduga berpengaruh terhadap habitat ikan dan pada akhirya berdampak terhadap hasil tangkapan ikan.

Waduk Djuanda dengan luas permukaan air maksimum 8.300 ha termasuk perairan yeng subur (eutrolik) dan sebagian besar (80%) dari luas tersebut merupakan wilayah limnetik. Studi struktur, makanan, dan kebiasaan makan komunitas ikan di wilayah limnetik Waduk Djuanda telah dilakukan selama 1 tahun dari bulan April 2003 sampai dengan Maret 2004. Penelitian ini bertujuan untuk mempelajad stalus struktur komunitas ikan dan peranan dalam memanfaatkan sumber daya pakan yang tersedia.