Spawning and Larval Development Dog Conch (Strombus Turturella)

Dog conch (Strombus turturella) is considered one of fishery commodities in Bangka Belitung Islands. This conch is often exploited and result in their populations are increasingly threatened. The aim of study to observe the reproduction and larval development of dog conch were studied under laboratory conditions. For the treatment of spawning the dog conch were placed in spawning tanks with a capacity of 1 ton. Stimulation of spawning is done by replacing the water in the tank as much as 90% every 24 hours until the eggs released by females. Spawning was preceded by copulation and fertilization occurs inside the female\u27s body.The results showed that the first egg cell divides into two cells after two hours of spawning. Then each cell continues to divide into four cells to become multicellular and reach the gastrula stage after 48 hours. Free swimming larval phase for four days and then settle down along with the formation of the first shell. The larvae will grow up to 5 mm shell length for 20 days

UJI COBA PENERAPAN TEKNOLOGI BUDIDAYA KERANG MUTIARA (Pinctada maxima) DI PERAIRAN TERNATE SELATAN, MALUKU UTARA

Usaha budidaya kerang mutiara di beberapa tempat di wilayah Indonesia umumnya hanya dapat dilakukan oleh badan usaha yang telah menguasai teknologi budidaya dari hulu sampai ke hilir dengan dukungan modal usaha yang relatif besar. Melalui sistem kemitraan,segmentasi pembesaran anakan kerang mutiara hingga mencapai ukuran layak jual dapat dijadikan sebagai peluang usaha bagi masyarakat. Penelitian ini bertujuan untuk mengetahui laju pertumbuhan dan tingkat kelolosan hidup anakan (spat) kerang mutiara di perairan Ternate Selatan, Maluku Utara. Informasi yang didapatkan dari hasil penelitian ini sebagai langkah awal untuk pelaksanaan kegiatan budidaya sistem kemitraan antara lembaga riset (LIPI) dan kelompok nelayan pelaksana budidaya serta para pemangku kepentingan (stake holder) di Maluku Utara.Larva kerang mutiara yang telah menempel pada lembaran spat kolektor dipelihara pad kolom air di laut, kemudian dilakukan penjarangan setelah anakan kerang mutiara mencapai ukuran rata-rata15 mm.Pemeliharaan selanjutnya menggunakan metoda tali rentang (long line method)dan pengamatan pertumbuhannya dilakukan setiap bulan. Hasil pengamatan menunjukkan bahwa bahwa pertumbuhan mutlak dan pertumbuhan harianterpanjang terjadi kelompok kerang yang dipelihara pada kedalaman 9 m yakni 28,41 mm dan 0,49 mm/hari. Sintasan terpanjang yang dihasilkan selama pemeliharaan mencapai 72.5 % pada kelompok kerang yang dipelihara pada kedalaman 3 m dan 9 m. Nilai rata-rata parameter perairan setempat berupa suhu adalah 29 oC, salinitas adalah 31o/oo, oksigen terlarut 6,0 ml/l dan pH 7.8.Kata kunci: Kerang mutiara, pembesaran, Maluku Utar

Zooplankton Sebagai Bioindikator Lingkungan Perairan: Studi Kasus Perairan Teluk Doreri Manokwari, Provinsi Papua Barat

The zooplankton ecological index which includes diversity, uniformity and dominance is one approach used to determine the condition of the aquatic environment. This study aims to determine the environmental status of the waters based on zooplankton ecological index which includes diversity, uniformity, and dominance in Doreri Bay water, Manokwari. This study was conducted in September 2020 at two 5- and 10-meter stations depth from the water's surface. Water quality measurements and water sampling were carried out at both stations thrice for 1 week. Water sampling to determine individual zooplankton used a 5 L volume Van Dorn. Temperature, salinity, and pH of the waters were measured successively using a rod-type thermometer with a 50 °C scale, a handheld refractometer RHSN-10ATC, and a pH meter of Orion A215 type. The measurement results obtained the temperature, salinity, and pH values ranging from 29.1 – 29.9 °C with an average of 29.5 °C, 30 – 35 ppt with an average of 33.2 ppt, and 7.9 – 8.3 with an average of 8.1, respectively. The diversity, uniformity, and dominance indexes ranged from 1.5 – 2.2, 0.7 – 1.0, and 0.1 – 0.4, respectively. The ecological status of Doreri Bay waters based on the diversity, uniformity, and dominance indexes show that the components of the food chain are still complete, including the producer and consumer groups and reducers. The effect of liquid waste from land activities around the bay has not disturbed the zooplankton

Studi Kualitas Air Kolam Ikan Air Tawar di Balai Benih Ikan Sentral Masni, Kabupaten Manokwari, Provinsi Papua Barat

Water quality parameters in pond include ammonia, nitrite, nitrate, phosphate, BOD, DO, turbidity, temperature, and pH. It is important to know the concentration of each component to properly minimize the negative impacts of their disturbances for the overall water quality and the biota in it. This study aims to determine the concentration of ammonia, nitrite, nitrate, phosphate, BOD, DO, turbidity, temperature, and pH in freshwater fish ponds at the Central Fish Seed Office (BBIS) of Masni, Manokwari Regency, West Papua Province. The study was conducted in May 2017, representing the rainy season, and August 2017, representing the dry season. Water samples were taken from settling, rearing, hatchery, and brood ponds. Meanwhile, standard method was implemented in the component measurements. The study results show that the concentrations of ammonia, nitrite, nitrate, and phosphate were 0.02-0.18 mg/L, 0.00-2.00 mg/L, 0.40-1.00 mg/L, and 1.01-21.83 mg/L, respectively. Furthermore, the concentrations of BOD and DO were 6.12-8.19 mg/L and 7.30-12.00 mg/L, respectively. Finally, the values ​​of turbidity, temperature, and pH were 0.40-9.99 NTU, 26-30°C and 7.7-8.5, respectively

SPATIAL VARIATION IN POPULATION CHARACTERISTICS OF VENUS CLAM GAFRARIUM TUMIDUM RÖDING, 1798 (BIVALVIA: VENERIDAE) IN AMBON BAY, MALUKU

Ambon Bay consists of two regions i.e. Inner and Outer Ambon Bay that was separated by Galala-Poka sill. Consequently these waters have different local environmental conditions that leads to the bivalve populations differences, one of them is venus clam Gafrarium tumidum. In this study, the distribution and spatial variation in population characteristics of of venus clam was quantified based on the analysis of their twelve shell dimensions from different populations. Fieldwork and analyses were conducted on April – Juni 2013. Total of 585 individuals of venus clam were found and could be divided into ten size-classes and three size categories i.e. small (< 23.11 mm), medium (23.12–32.05 mm) and large size (> 32.06 mm). The highest size-class density was found at medium size. Spatial distribution was related to the characteristics of sediment and other potential factors. Result of discriminant analysis showed that shell-width (SW) was the variable with the highest discriminating power and distinguishing between Inner and Outer Ambon Bay populations