Preliminary Findings on Distribution of Bali Sardinella (Sardinella lemuru) in Relation to Oceanographic Conditions during Southeast Monsoon in Bali Strait Using Remotely Sensed Data

Bali sardinella (Sardinella lemuru) is the main fishing catches in Bali Strait. The distribution of S. lemuru and its preferred oceanographic condition were investigated from remotely sensed data. The objectives of this study were to elucidate the distribution of S. lemuru and the preferred oceanographic condition of S. lemuru in Bali Strait using remotely sensed data. Sea surface temperature (SST) and sea surface chlorophyll-a (chl-a) were downloaded from ocean colour website meanwhile the fishing location generated from daily Visible Infrared Imaging Radiometer Suite (VIIRS) boat detection (VDB), downloaded from NOAA website. The results showed that at the beginning of southeast monsoon (April), most of the fishing location appeared in the north part of Bali Strait, and moved to south part of Bali Strait at the end of the southeast monsoon (September). The results also revealed that most of fishing location of S. lemuru located in SST value of 26 – 30 °C and chl-a value of 0.3 – 0.8 mg/m3. Integration VDB data and oceanographic condition generated from remotely sensed data could form the basis for fisheries management and information system, such as S. lemuru in Bali Strait, in the future.

Hydro-oceanographic condition (Tide, Sea Current, and Waves) of Nongsa Batam Sea

Tanjung Bemban is one of the seas found in the Nongsa sub-district, Batam city which is currently developed as a tourist attraction. This research aims to find out the hydro-oceanographic component, which consists of tide and the current and wave pattern in the sea of Tanjung Bemban Nongsa. To collect the data regarding tide, Tide Pole method, using measuring sign, is used, To collect data of sea current, Float Tracking (Lagrangian) method, by measuring distance and displacement of floating objects in the sea, is utilized, To collect the data of the wave, Wave Pole method, by measuring wave height, is employed. Based on the result of the research, it is clear that the tide of the sea is categorized as the semi diurnal, since there are two tides in one day with identical height, which occur sequentially and regularly. The highest flow reaches 260 cm and the lowest ebb 19 cm in the 4 days of observation, with 15 minutes interval. The measuring of ocean current is carried out for every 30-second intervals. Current velocity in Nongsa sea ranges from 0.02 m/s to 0.26 m/s. The current moves from east to southwest and west, even though some move northwest and north. Wave height is quite low, between 18 cm and 23 cm. Hydro-oceanographically, the Tanjung Bemban Nongsa area can be developed into a strategic tourism area

ANALISIS KERENTANAN JENIS IKAN PELAGIS KECIL DI PERAIRAN SELAT BALI DAN SELAT MAKASSAR TERHADAP DINAMIKA SUHU PERMUKAAN LAUT

<p>Kondisi oseanografi Indonesia dipengaruhi oleh dinamika proses oseanografi global. Salah satu proses tersebut adalah Arlindo yang menghantarkan massa air bersuhu hangat dari Samudera Pasifik ke Samudera Hindia melalui Selat Makassar. Dinamika suhu perairan akan mempengaruhi kondisi sumberdaya ikan di perairan tersebut. Penelitian bertujuan untuk menganalisis dampak dinamika suhu permukaan laut terhadap empat jenis ikan pelagis yaitu ikan layang biru (Decapterus macarellus), kembung (Ratrelliger kanagurta), lemuru (Sardinella lemuru) dan tongkol (Auxis thazard). Penelitian dilakukan pada tahun 2015 dengan membuat profil biologis setiap jenis ikan, kemudian dilakukan penilaian oleh para ahli mengenai kerentanan setiap jenis ikan terhadap paparan dinamika SPL. Hasil penilaian para ahli kemudian dianalisis menggunakan metode kerentanan jenis yang digunakan oleh NOAA. Hasil analisis menunjukkan bahwa empat jenis ikan pelagis yang dianalisis mempunyai tingkat kerentanan yang rendah terhadap paparan dinamika suhu permukaan laut. Tingkat kerentanan ikan pelagis kecil di perairan Selat Bali lebih tinggi bila dibandingkan dengan Selat Makassar.</p><p> </p><p><em>Oceanographic condition of Indonesian waters is highly influenced by global oceanographic processes. Indonesian through flow is one of the global oceanographic processes that affect the oceanographic condition in Indonesia waters, it delivers warm water from Pacific Ocean to Indian Ocean through the strait of Makassar. Therefore, the dynamic of sea water temperature will affect the fish resources condition. The objective of this study is to analyze the impact of the dynamic of sea surface temperature to pelagic fishes such as mackerel scad (Decapterus macarellus), Indian mackerel (Ratrelliger. kanagurta), Bali sardine (Sardinella. lemuru) and frigate tuna (Auxis. thazard). The study was conducted in 2015 consists of three phases of process, describing biological profile of the species, then scoring based on expert adjustment, and analyzed the expert scores using NOAA’s standard method of species vulnerability to climate change. The result showed that all of species analyzed have low vulnerability to the expose of the dynamic of sea surface temperature. The rank of vulnerability of all species is higher in Bali Strait than Makassar Strait. </em></p>