PRELIMINARY STUDY OF FISH DIVERSITY IN PABEAN BAY, INDRAMAYU

Pabean Bay is an estuary waters in which salinity fluctuations occur. This fluctuation requires that the fish living in this location have the ability to adapt. This research is a preliminary study that aims to identify the diversity of fish species in these waters. The study was conducted from January to June 2015 with sampling at intervals of one month. Fishing was carried out at three stations, namely the inside which is the estuary of the river, the middle part and the outside of the estuary to get a representative sample. The fishing gear used are sero, and trammel nets. During the study, it was found that 78 species of fish were included in 39 families. The number of species in each sampling varies. Among the fish found were mainly the family Gobiidae (10 species) and the Family Leiognathidae, Lutjanidae, Sciaenidae and Tetraodontidae (four species each). Several fish species were found in the larval, juvenile and adult stages, and these conditions illustrate the importance of estuaries in the survival of the fish life cycle

Musim Pemijahan Ikan Pelangi Arfak (Melanotaenia Arfakensis Allen) Di Sungai Nimbai Dan Sungai Aimasi, Manokwari [Spawning Season of Arfak Rainbowfish (Melanotaenia Arfakensis Allen) in Nimbai and Aimasi Streams, Manokwari]

The study was aimed to describe the spawning season of arfak rainbowfish (Melanotaenia arfakensis) in Nimbai and Aimasi streams, both are located in Prafi river system. Sampling was conducted from June to December 2007 and carried out monthly in four different habitat types using hand net. A total of 752 individual specimens were collected and consisted of five developmental stages, namely egg, larvae, juvenile, young and adult. There was no different proportion in both sexes, either habitat type or time. This species has relatively low fecund, producing approximately 23-1,351 eggs with relatively large diameter (0.5-1.3 mm). Large egg diameter was distributed in posterior of ovaries, with 2-3 modes, and presence of atretic eggs, and was indicated as multiple spawner fish. However, based on gonado somatic index, condition factor, presence of eggs and larva in limited period showed that there were increased reproductive activities in both locations from June to September, with low water flow condition. Concentration of reproduction activity during dry season to ensure that larva was produced relatively stable and in benign physical condition. In order to maintain the population of this species, both of these streams should be reserved as their natural habitats, thereby its life cycles could go on

KUALITAS PERAIRAN DI TELUK DORERI KABUPATEN MANOKWARI

Pasar Sanggeng, pasar Wosi, pelabuhan, PLTD (Pembangkit Listrik Tenaga Disel), perhotelan dan pemukiman penduduk yang terletak di pesisir Teluk Doreri Kota Manokwari, menjadi salah satu pusat aktivitas yang melayani kebutuhan masyarakat. Akibat adanya aktivitas yang tinggi tersebut menyebabkan pembungan sampah-sampah organik dan anorganik tidak terawasi atau terkontrol dengan baik. Kondisi ini berlangsung secara terus menerus setiap hari sehingga dapat menyebabkan terjadi degradasi kualitas perairan. Tujuan Penelitian yaitu untuk mengetahui status kualitas perairan di Teluk Doreri Kabupaten Manokwari. Penelitian dilakukan dari bulan Agustus tahun 2016 bertempat di Laboratorium Kelautan, Ilmu Kelautan Unipa dan Laboratorium Prolink IPB Bogor. Lokasi pengambilan sampel air di sekitar perairan Sawaibu, Wosi, Andai, Sowi dan Perairan Maruni. Data parameter yang diambil melalui pengukuran langsung dan tidak langsung. Pengukuran secara langsung meliputi parameter salinitas, pH, suhu dan oksigen terlarut. Sedangkan pengukuran tidak langsung dengan cara mengambil sampel air. Pengambilan sampel air digunakan untuk penentuan parameter kekeruhan, nitrat, fosfat dan logam berat. Sampel air tersebut langsung dimasukan dalam botol polyetelin dan dikirim ke Prolink IPB Bogor untuk dianalisis. Pengukuran mengacu pada Standard Methods for the Examination of Water and Wastewater (APHA, 1998). Hasil penelitian dari lima lokasi di perairan Teluk Doreri berkisar antara 0,17 – 6,16 NTU untuk kekeruhan, 4,64 – 5,04 untuk pH, 5,1 -6 mg/L untuk oksigen terlarut, 30 – 33 ‰ untuk salinitas, 29, 8 – 30,6 oC untuk suhu air, 0,1 -0,8 mg/L untuk nitrat dan fosfat berkisar 0,08 – 0,16 mg/L. Hasil logam berat cadmium (Cd) menunjukan potensi toksik yang tinggi bagi biota perairan di Teluk Doreri. Parameter logam berat cadmium, nitrat dan fosfat sangat mengkuatirkan serta dapat menyebabkan gangguan terhadap lingkungan khususnya bagi biota perairan. Parameter – parameter tersebut telah melampaui baku mutu yang ditetapkan kementerian lingkungan hidup no 51 tahun 2004.WATER QUALITY IN THE DORERI BAY DISTRICT MANOKWARI. Traditional markets (Pasar Sanggeng and Wosi), port, PLTD (Power Plant), hotels and residential areas are located in the cost of Doreri bay in Manokwari district. Activities in those areas create organic and inorganic wastes that have been used the Doreri bay as a water dump. The waste has been dumped since long time ago and continue up to nowadays.  That cause water quality degradation of Doreri bay. The research objective was to determine the status of water quality in Doreri Bay, Manokwari Regency. The water quality study has been carried out in August 2016 in Marine laboratory of UNIPA and Prolink laboratory in IPB. Water samples collected from Sawaibu, Wosi, Andai, Sowi and Maruni beach.  Data were divided base on the data collection which is directly and indirectly collected. Water salinity, pH, temperature and dissolved oxygen are direct data collection. Turbidity, nitrate, phosphate and heavy metals are indirect data collection that has been analyzed in Prolink IPB. The water has been analyses by using Standard Method for Examination of Water and Wastewater (APHA, 1998). The results show that turbidity of five areas range from 0.17 to 6.16 NTU, pH range from 4.64 to 5.04, dissolved oxygen between 5.1 -6 mg/L, water salinity range from 30-33%, water temperature between 29, 8 - 30.6 oC, 0.1 -0.8 mg/L for nitrate and phosphate between 0.08 - 0.16 mg/L. Heavy metal (cadmium) showed high potential toxic risk on the biota of Doreri bay. Cadmium, nitrate, and phosphate are a heavy metal that categorized as concerned pollutant to the Dorery bay. Those heavy metal have been exceeded the water quality standard base on Ministry of environment number 51-2004.

feeding effectivity of the arfak rainbowfish melanotaenia arfakensis allen 1990 on difference of water turbidity level a laboratory approach

The research on feeding effectivity of arfak rainbowfish conducted at Fisheries Laboratory, Faculty of Fishes and Marine Scince, University of Papua in July to December 2016. The purpose of this research is to describe feeding effectivity of the fish at several levels of water turbidity. The fish samples used in the treatment, collected from Nimbai Stream, Prafi River system, Manokwari were acclimatized for a month in the laboratory. The fish were selected based on the body length and categorized into six size classes. Each individual of the fish was treated with 200 individuals of mosquito larvae (instar IV stage) at seven turbidity levels (2.54, 25.07, 50.52, 100.20, 500.60, and 800.40 Nephelome-tric Turbidity Unit, NTU) using particles with size of <63um. Feeding effectivity was indicated by the level of preda-tion in a period of 15 minutes. The results of the research showed that average level of predation did not differ among size classes at the low level of turbidity (<50,52 NTU). The significant decrease in the average level of predation occurred at the higher level of turbidity (<100,12 NTU) with the values range from 23.2% to 65.9%. This indicated a decrease in the feeding effectivity as the turbidity levels increase. AbstrakPenelitian efektivitas ikan pelangi arfak dalam mencari makan dilaksanakan di Laboratorium Perikanan FPIK Univer-sitas Papua pada bulan Juli sampai Desember 2016. Tujuan penelitian ini untuk mendeskripsikan efektivitas ikan pela-ngi arfak mencari makan pada beberapa tingkat kekeruhan air. Contoh ikan yang digunakan dalam perlakuan dikoleksi dari Sungai Nimbai, sistem Sungai Prafi, Manokwari yang diaklimatisasi selama satu bulan di laboratorium. Individu ikan yang digunakan dalam penelitian ini dipilih berdasarkan panjang tubuh dan dikelompokkan ke dalam enam kelas ukuran. Setiap individu ikan diberi perlakuan pakan berupa larva nyamuk (tahap instar IV) sebanyak 200 individu pada tujuh tingkat kekeruhan yang berbeda (2,54; 25,07; 50,52; 100,20; 200,20; 500,60 dan 800,40 Nephelometric Turbidity Unit, NTU) dengan menggunakan partikel berukuran <63um. Efektivitas mencari makan akan ditunjukkan berdasarkan tingkat pemangsaan dalam periode 15 menit. Tingkat pemangsaan rata-rata tidak berbeda pada tingkat kekeruhan yang rendah (<50,52 NTU) dalam setiap kelas ukuran. Penurunan tingkat pemangsaan rata-rata secara nyata mulai berlang-sung pada tingkat kekeruhan yang lebih tinggi (<100,12 NTU) dengan nilai sebesar 23,2%-65,9%. Kondisi ini menun-jukkan penurunan efektivitas mencari makan seiring dengan semakin meningkatnya tingkat kekeruhan air

Aktivitas Pemijahan, Perkembangan Awal, dan Pertumbuhan Larva Ikan Pelangi Arfak dalam Kondisi Laboratorium: Studi Pendahuluan untuk Penangkarannya

Comprehensive information regarding the reproduction, early development, and growth of larvae is very important in the efforts of captive breeding and reintroduction of endangered fish species. One of the species that is starting to be threatened is the Arfak rainbowfish, Melanotaenia arfakensis which is already in the vulnerable category and its information is still relatively limited. Therefore, this study was conducted to describe the spawning activity, early development, and growth of the larvae of this rainbow fish species under laboratory conditions. Experiments on a laboratory scale were carried out in March-September 2017. The fish used came from the Nimbai Stream. A total of three pairs of individual males and females ranging in size from 46.5 to 60.1 mm were selected for treatment. However, only one pair was successfully observed spawning activity completely. Spawning takes place between morning and noon in three spawning periods. In each period, spawning lasts between 8 and 11 days. Between spawning periods takes 14 to 22 days. After fertilization, the eggs are attached with filaments to the spawning substrate and placed at a depth of 7.3-24.3 cm from the surface of the water. One group of eggs spawned consists of 78-116 eggs with a diameter range between 1.05 and 136 mm. The eggs hatch in a period of 4 to 10 days. The body length of the newly hatched larvae ranges from 4.13-4.40 mm and will reach a size of 7.85 mm with a survival rate of 48.1% after 41 days. The results of this study found several advantages from the characteristics of spawning and growth in the early stages that are useful for captive breeding efforts and reintroduction of this rainbowfish to their natural habitat. Thus, its population in the Prafi River system can be maintained.Informasi yang lengkap mengenai reproduksi, perkembangan awal, dan pertumbuhan larva menjadi sangat penting dalam upaya penangkaran dan reintroduksi spesies ikan yang terancam punah. Salah satu di antara spesies yang mulai terancam adalah ikan elangi Arfak, Melanotaenia arfakensis yang sudah berada dalam kategori rentan dan informasinya masih sangat terbatas. Oleh karena itu, penelitian ini dilakukan dengan tujuan untuk mendeskripsikan aktivitas pemijahan, perkembangan awal, dan pertumbuhan larva spesies ikan elangi ini dalam kondisi laboratorium. Percobaan dalam skala laboratorium dilaksanakan pada bulan Maret-September 2017. Ikan yang digunakan berasal dari Sungai Nimbai. Sebanyak tiga pasang individu jantan dan betina dengan kisaran ukuran 46,5 sampai 60,1 mm dipilih untuk perlakuan. Namun, hanya satu pasangan yang berhasil diamati aktivitas pemijahannya secara lengkap. Pemijahan berlangsung di antara waktu pagi hari sampai siang hari dalam tiga periode pemijahan. Dalam setiap periode, pemijahan berlangsung di antara 8 dan 11 hari. Antarperiode pemijahan membutuhkan waktu 14 sampai 22 hari. Setelah dibuahi, telur dilekatkan dengan filamen pada substrat pemijahan dan diletakkan pada kedalaman 7,3-24,3 cm dari permukaan air. Satu kelompok telur yang dipijahkan terdiri atas 78-116 butir dengan kisaran diameter di antara 1,05 dan 136 mm. Telur menetas dalam periode 4 sampai 10 hari. Panjang tubuh larva yang baru menetas berkisar 4,13-4,40 mm dan akan mencapai ukuran 7,85 mm dengan tingkat sintasan 48,1% setelah 41 hari. Hasil penelitian ini menemukan beberapa kuntungan dari karakteristik pemijahan dan pertumbuhan tahap awal yang bermanfaat untuk upaya penangkaran dan pelepasliaran ikan ini ke habitat aslinya. Dengan demikian, populasinya di sistem Sungai Prafi dapat tetap dilestarikan