Totok Hestirianoto

Sound characteristics of Terapon Fish (Terapon jorbua) as a response to temperature changes

The change in water temperature has a potential impact on the behavior of aquatic animal including fish which was generated by their sound productivity and characteristics. This research aimed to study the response of sound productivity and characteristics of Terapon jorbua to temperature change. As a response to temperature increases, Terapon jorbua have decreased the number of sound productivity. Two characteristic parameters of fish sound, i.e., intensity and frequency were quadratically increased during the water temperature rises. In contrast, pulse duration was quadratically decreased.

ANALISIS DAN KLASIFIKASI SEDIMEN PERMUKAAN DASAR LAUT MENGGUNAKAN SUB-BOTTOM PROFILER

Peningkatan aktivitas manusia di bidang kelautan seperti operasi pengerukan ( dredging ), eksplorasi minyak dan gas, penambangan pasir mineral, dan berbagai penelitian kelautan telah mengakibatkan permintaan yang mendesak terhadap peta dasar laut yang akurat. Sub-bottom Profiler (SBP) adalah sistem akustik tradisional yang digunakan untuk menggambarkan lapisan sedimen dan batuan di bawah dasar laut, serta memberikan informasi tentang ketebalan sedimen dan stratigrafinya. Oleh karena itu, tujuan dari penelitian ini yaitu menentukan profil lapisan sedimen dasar laut ( near-surface sediment ) dan memperoleh nilai koefisien refleksi dari lapisan tersebut. Proses akuisisi data dilakukan menggunakan SBP jenis sparker single channel oleh BPPT, yaitu survei pemeliharaan pipa migas dan kabel listrik Pertaminatahun 2010 yang berada di sebelah timur pantai Balongan, Indramayu. Pengambilan sampel sedimen dasar laut menggunakan gravity corer. Hasil dari pengolahan data mentah SBP dengan Matlab di dekat lokasi B19 diperoleh profil 2D dari lapisan sedimen dimana terlihat jelas dasar laut dan reflektornya serta memiliki nilai koefisien refleksi berkisar 0 hingga 0.2955. Selain itu teknik analitis untuk estimasi parameter sedimen dari data laboratorium ditunjukkan sebagai pembanding. Hasil sedimennya berupa silt/ lanau dengan nilai koefisien refleksinya adalah 0.2807.

Bioacoustic Spectral Whistle Sound and Behaviour of Male Dolphin BottleNose (Tursiops aduncus) at Safari Park Indonesia, Cisarua Bogor

Whistle sound is generally used for echolocation purposes, while the sound of the blast-beat and whistles play a major role in internal and inter-group communication. The purpose of this research is to know the power spectral patterns and fluctuations in sound based on frequency and Power Spectral Density (PSD) of the sounds produced by dolphins and observing the position of dolphins, Noisy Time Domain (NTD) and behavior using underwater camera, and also comparing between time and sound spectrum. Data recording was taken at the Safari Park of Cisarua Bogor in Indonesia, by taking data in show pool and show pool. The results showed that salinity before feeding time in the show pool with replication 1,2, and 3 has salinity value that is equal to 30%. Data at the show pool before feeding with replications 1,2, and 3 has a salinity of 29%. Power Spectral Density (PSD) of the whistle sound before feeding was different from one another, but it has the same frequency range. The highest intensity values is at sound whistle 3 before feeding time at the show pool with an intensity value of 28.03 dB/Hz with frequency interval of 14642-16000 Hz. F-test at the show pool before meals has heterogeneous value. Treat before meals at the show pool has a value of P < 0.001 and P < 0.001. Value Noisy Time Domain has differences with each other and has a lot of different sound patterns. In general, there are real differences are evidenced by F test on a range of time at each whistle on physiotherapy and swimming pool show in the time before meals. The position of dolphins in a pool show more dominant and often in the bottom of the pool, the position of the dolphins affects the frequency.

THE DETECTION OF PELAGIC FISH USING HYDROACOUSTIC IN PALU BAY, CENTRAL SULAWESI

Data potensi dan hasil tangkapan yang bersumber dari data statistik perikanan ataupun perikanan komersial sebagian besar belum lengkap dan akurat. Oleh sebab itu, upaya peningkatan akurasi data dan metode survey yang sesuai diperlukan untuk menjamin ketepatan sasaran pendugaan potensi sumberdaya ikan di Indonesia. Tujuan deteksi schooling ikan pelagis dengan hidroakustik ialah agar dapat memberikan gambaran akurat tentang kondisi insitu potensi sumberdaya ikan pelagis di Perairan Teluk Palu. Hasil penelitian menunjukkan bahwa schooling ikan pelagis dominan berada pada interval TS -70 dB s/d -40 dB sebanyak 23 schooling ikan. Berdasarkan strata kedalaman, schooling ikan lebih banyak berada pada kedalaman 100 s/d 150 m sebanyak 12 schooling disusul pada kedalaman 0 s/d 50 m sebanyak 9 schooling dan kedalaman 50 s/d 100 m sebanyak 2 schooling. Nilai TS tersebut merupakan kisaran nilai dari jenis pelagis besar. Hal tersebut sejalan dengan hasil tangkapan ikan di perairan Teluk Palu yang didaratkan di Pelabuhan Perikanan Labuan Bajo, Kabupaten Donggala yang didominasi jenis ikan pelagis besar. Ukuran terpanjang ikan cakalang senilai 74 cm di kedalaman 142 m. Ukuran terkecil senilai 5 cm di kedalaman 57 m dengan rata-rata ukuran 27.80 cm.Yield and catch data obtained from statistic and fisheries commercial data are incomplete and inaccurate. Effort to increase the accurate data and survey method become necessary to estimate the yield potential in Indonesia. The aim of this study is to detect the pelagic schooling (target strength/TS approach) by using hydroacoustic. Those detection are used to describe insitu condition of pelagic fishes in Palu Bay, Central Celebes. Result of this study showed that the range of TS interval of pelagic schooling are between -70dB to -40dB, found about 23 schools. Based on depth strata, dominant schooling (12 schools) found in 100 to 150 m, then followed by 9 schools in 0 to 50 m and 2 schools in 50 to 100 m. fish caught in Palu Bay that landed in Labuan Bajo fishing port dominate by large pelagic. Those information are relevant with the TS data. The longest size of skipjack is 74 cm in depth of 142 m. Medium size of the smallest value of 5 cm in depth 57 m with an average size of 27.8 cm.

Computation of Single Beam Echo Sounder Signal for Underwater Objects Detection and Quantification

Underwater Acoustic methods have been extensively used to locate and identify marine objects. These applications include locating underwater vehicles, finding shipwrecks, imaging sediments and imaging bubble fields. Ocean is fairly transparent to sound and opaque to all other sources of radiation. Acoustics technology is the most effective tool for monitoring this environment because of the sounds ability to propagate long distance in water. We used single beam echo sounder to discriminate underwater objects. Development of the algorithm and applied it to detect and quantify underwater object such as fish, sea grass, and seabed. We found the detected target has different backscatter value.