Jurnal Ilmu dan Teknologi Kelautan Tropis
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WATER QUALITY AND ITS EFFECT ON GROWTH AND SURVIVAL RATE OF LOBSTER REARED IN FLOATING NET CAGE IN EKAS BAY, WEST NUSA TENGGARA PROVINCE
Get PDFABSTRACT The development of lobster farming in floating net cage in Ekas Bay caused an environmental degradation such as decrease water quality due to some aquaculture wastes. The purposes of this study were to determine the status of water quality and their effect on growth and survival rate of lobster reared in floating net cages (FNC) in the Ekas Bay, West Nusa Tenggara Province. Water sample collection and handling referred to the APHA (1992). Analyses of water quality data were conducted using Principal Component Analysis. Determination of the water quality status of Ekas Bay was performed with STORET system. Multivariate analyses were used to determine the relationship between water quality, growth, and survival rate of lobster reared in FNC. Results showed that Ekas Bay water quality status was categorized in class C (medium contaminated), which exceeded some quality standard parameters such as ammonia (0.3 mg/l), nitrate (0.008 mg/l), and phosphate (0.015 mg/l). During lobster farming activities feeding with trash fish for 270 days, we obtained daily growth rate of 0.74% (lower than normal growth rate of 0.86%), survival rate of 66% (lower than normal survival rate of 86.7%), and feed conversion ratio of 11.15. Ammonia was found as a dominant factor reducing growth and survival rate of lobster reared in FNC. Keywords: water quality, lobsters, growth, survival, Ekas Ba
A NUMERICAL MODELING STUDY ON UPWELLING MECHANISM IN SOUTHERN MAKASSAR STRAIT
Get PDFABSTRACT While it has been well documented in the previous studies that upwelling events in the southern Makassar Strait (MAK) during the Southeast Monsoon (SEM) period are associated with low sea surface temperature (SST) and high chlorophyll-a (Chl-a) concentrations in the seawater, the dynamic and physical processes that trigger these upwelling events are still less well understood. In the present study we proposed a mechanism of the upwelling event using a numerical model of the Regional Ocean Modeling System (ROMS). Model validations showed a high correlation of SST climatology between the model and the NOAA-AVHRR satellite data. Moreover, velocity fields of the Indonesian Throughflow (ITF) Makassar in Libani Channel was well reproduced by proposed model, revealing an intensification of the flow centered near 120 m depth, which is in good agreement with the observation data. The model demonstrated that during the SEM period strong southeasterly winds that blow over southern Sulawesi Island can increase high vertical diffusivity and heat loss through heat flux. Hence, these physical processes lead to increased vertical mixing that, in turn, generates low SST, as a proxy of upwelling event. Furthermore, the upwelling process is enhanced by the ITF Makassar jet that creates large circular eddies flow due to complex topographic within the triangle area of southern Makassar - eastern Java Sea - western Flores Sea. The eddies generate the area of convergence offshore along the ITF pathways and divergence area in the coastal waters close to southern Sulawesi Island. Model experiment with closing/opening Selayar Strait revealed a change of intensity and area of upwelling, suggesting that the Selayar Island forms a barrier for the outflow from MAK to northern part of Flores Sea. Keywords: Upwelling, ITF Makassar, SE monsoon winds, ROMS-AGRIF, Makassar Strait
ANTIOXIDANT ACTIVITY OF SELECTED FORMULA Spirulina platensis TROCHES BASED ON PYSICAL CHARACTERISTICS
Get PDFABSTRACT Spirulina contains complete nutrition and bioactive components as a source of antioxidants. The aims of this research were to determine a formula of troche from Spirulina platensis according to the physical characteristic standard of the Indonesian Health Ministry, and to determine the antioxidant activity of the selected troche from Spirulina platensis. This research was conducted in three stages. The first stage was troches formulation. The second stage was troches physical analyses, including weight uniformity, friability, hardnes, and disintegration time. The third stage was to determine the antioxidant activity of the selected formula of troche from Spirulina platensis. There were five formulas of troches i.e., FTS 1, FTS 2, FTS 3, FTS 4, and FTS 5. The troche consisted of Spirulina platensis powder, carrageenan, gelatin, corn flour, sugarleaf, and mint powder. Based on the weight uniformity of the troche, all formulas met the standard. However, according to friability aspect, the best formula was FTS 1 with rate of 1.7%. The hardness of five formula ranged from 0.65 to 2.3 Kp, and none met the standard. The best formula based on disintegration time measurement was FTS 1 (24:47 minutes). Based on the physical characteristics of the troches, the selected formula was FTS 1. The antioxidant activity (IC50 of the selected formula (FTS 1) was 288,68 ppm. Keywords: antioxidant, troches, physical characteristics of troches, Spirulina platensi
TOPOGRAPHICALLY INDUCED TURBULENCE ON CONTINENTAL SHELF OFF JOGASHIMA, SAGAMI BAY, JAPAN
Get PDFABSTRACT Direct turbulence measurements using TurboMAP over a “small ridge” on the continental shelf off Jogashima, Sagami Bay, Japan revealed an active layer of topographically induced turbulence. The active layer ( = 10-7 - 10-6 W kg-1) located at mid-depth of 200 – 250 m, occurred on alternate side of “small ridge” depending on the direction of the tidal current. This active layer was accompanied by rebounded-isopycnal surfaces 26.0 - 26.1 σθ , in which all in qualitative manner showed an internal hydraulic flow control on the shelf. The turbulence friction velocity was two order of magnitude lower than observed- in this active layer explaining a less role of bottom friction than hydraulic flow to the high turbulence layer. Keywords: topographically induced turbulence, continental shelf, internal hydraulic flo
GROWTH RESPONSE OF WHITE SHRIMP (Litopenaeus vannamei) REARED IN LOW SALINITY MEDIUM, FED DIFFERENT PROTEIN AND CALCIUM LEVELS
Get PDFThe white shrimp (Litopenaeus vannamei) has been an important commercial shrimp species in Indonesia. This species is tolerance to low salinity therefore, it is important to develop its aquaculture. The purpose of this study was to study the effect of protein and calcium levels in diet on growth performance of the white shrimp post larvae. A factorial experiment at three levels of dietary protein (25, 35, 45%) and three levels of calcium (0, 2, 4%) with three replicates were used in this experiment. Fifteen shrimps (PL25) were placed in triplicate 45-l glasses aquarium. Salinity in shrimp aquarium was 2 ppt. The shrimps were fed of about 8% of body weight four times per day for 28 days. Measured parameters were daily growth rate, feed efficiency, RNA/DNA ratio, frequency of moulting, calcium and protein retentions. Results showed that shrimp fed on diet 45% protein and 2% calcium levels produce higher daily growth rate, feed efficiency, RNA/DNA ratio, protein retention, compared to the other treatments. It was concluded that the white shrimp post larvae required 45% protein and 2% calcium for the shrimp maintenance in a low salinity condition. Keywords: protein, calcium, RNA/DNA ratio, moulting, Litopenaeus vanname
WATER MASSES CHARACTERISTICS AT THE SANGHIE TALAUD ENTRY PASSAGE OF INDONESIAN THROUGHFLOW USING INDEX SATAL DATA 2010
Get PDFABSTRACT Measurement of ocean physical parameters using the CTD was conducted by deep water expedition INDEX-SATAL 2010 (Indonesian Expedition Sangihe-Talaud) in July-August 2010. The aim of this study was to determine the characteristics of water masses around the Sangihe Talaud Water where there was an entry passage of Indonesian throughflow (ITF) at the west pathway that passed through the primary pathway i.e., the Sulawesi Sea and Makassar Strait and the secondary pathway (east pathway) that passed through the Halmahera Sea. The analyses were performed by the method of the core layer and was processed with software Ocean Data View (ODV). The results showed that in the Sangihe Talaud waters there was a meeting water masses from the North Pacific and the South Pacific. The water mass characteristics in main pathway through the Sulawesi Sea was dominated by surface and intermediate North Pacific water masses and carried by the Mindanao Currents. While the Halmahera Sea water mass was dominated by surface and intermediate South Pacific water masses carried by the New Guinea Coastal Current that moved along the Papua New Guinea and Papua coast enters to the Halmahera Sea. Keywords: Index-Satal 2010, Northern Pacific Water Masses, Southern Pacific Water Masses, Sangihe Talau
DISTRIBUTION OF GASTROPODA AND ITS RELATION WITH ENVIRONMENTAL CHARACTERISTICS IN COASTAL WATERS OF NUSALAUT ISLAND, CENTRAL MALUKU
Get PDFNusalaut Island is one of the small islands in Maluku waters that is influenced by the dynamics of Banda Sea. The aim of this study was to investigate the density and spatial distribution of gastropods and its relation with environmental characteristics using multivariate analysis i.e., Principal Component Analysis (PCA) and Correspondence Analysis (CA). This study was conducted in Nusalaut Island as a part of Marine Resources Inventory Programme in Nusalaut Island in 2009. Fieldwork was conducted in northern Nusalaut Island using systematic random sampling method. Results showed that the highest density was Nassariidae family and other low density were from the familes of Cerithiidae, Buccinidae, Terebridae, and Conidae, respectively. The environmental characteristics affected species composition and density of gastropods. Distribution of environmental characteristics and spatial distribution of gastropods at each station was influenced by a combination of several parameters. Microhabitat pattern, predatory, and human activities also affected the distribution of gastropods. Keywords: gastropoda, spatial distribution, environmental characteristics, Nusalaut Islan
COMMUNITY SOCIAL-ECOLOGY DYNAMICS ON MADAK CULTURE OF COASTAL REGION, WEST SUMBAWA
Get PDFABSTRACT Madak activity is a local word for the people of Sumbawa to collect marine biota in tidal area during the low tide. The purpose of this study was to determine social change in communities of West Sumbawa for doing Madak culture. The study was conducted for 2 months in West Sumbawa. Data were collected through observation, questionnaire, and interviewing the Madak people. It seemed that Madak culture changed totally, especially in daily actvities. In the past, they used tools that were environmentally friendly. However, during this study, they tended to damage coastal environment by flipping the reef. Keywords: Social, ecology, Madak culture, west Sumbaw
TIDAL RANGE CALCULATION BASED ON THE LOCAL KNOWLEDGE OF THE SAMA ETHNIC GROUP IN THE EASTERN INDONESIA
Get PDFThe Sama ethnic group (Bajo) is well known as “Indonesian marine people” that dominantly spreaded in coastal region of eastern Indonesian region. Their activities have been adapting with the territorial water as shown in the determination of their home floor height to prevent from the tidal flood. The purpose of this study was to examine the accuracy of the tidal range calculation by local knowledge of the Sama ethnic group (Sama Ethnic Method, SEM). The analysis was done by comparing tidal range result calculated by the Sama Ethnic Method (SEM) with the standardized tidal harmonic constituents. The result showed that the 2nd tidal peaks (DLB-s) in the 15th “Sya’ban” date was the best date to do measurement of a tidal range. In this case, the “Likkas Silapas” (LS) value at the above date was above the mean height water level (MHWL). Meanwhile, in other dates, the LS value was under MHWL value. The result also showed a strong correlation (R2> 90%) between rasio of tidal high on 1st and 2ndpeaks (DLB-s/DLB-m) on 15th Sya’ban date and LS-s value. The local knowledge of the Sama Ethnic Method to determine the tidal range was effective and scientifically proven. Keywords: the Sama Ethnic group, tidal range, Likkas Boe, Likkas Silapas, Sya’ba
TURBULENT MIXING IN OMBAI STRAIT
Get PDFOmbai Strait is one of the exit passages of Indonesian Throughflow (ITF) which conveys hotspot of strong internal tidal energy. Internal tide is the one of main energy which causes mixing processes in the oceans and could lead to changes in water mass characteristics. The purpose of this research was to estimate the turbulent mixing by using Thorpe analysis. Nine CTD cast were obtained for one tidal cycle (24 hours) in Ombai Strait. The results showed the average value of the turbulent mixing is 833.5 x 10-4 m2s-1, the highest found in deep homogeneous layer (2383.4x 10-4 m2s-1), followed by mixed surface layer (103.0 x 10-4 m2s-1) and thermocline (14.2 x 10-4 m2s-1). This Turbulent mixing value is much higher than the previous measurement in Indonesian Sea. This is presumably due to the strong internal tidal energy and its interaction with existing deep sill in Ombai Strait. Keywords: Indonesian throughflow (ITF), Ombai Strait, turbulent mixin