Dharmadi, Dharmadi
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BIODIVERSITY OF SHARKS AND RAYS IN SOUTH EASTERN INDONESIA Dharmadi, Dharmadi; Fahmi, Fahmi; White, William
Indonesian Fisheries Research Journal Vol 15, No 2 (2009): (December 2009)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (7185.459 KB) | DOI: 10.15578/ifrj.15.2.2009.17-28

Abstract

Indonesia has a very diverse shark and ray fauna and is the largest chondrichthyan fisheries in the world. Most of the sharis are caught by longlines and gillnets and rays are caught both as target, e.g. in the tangle net and demersal gillnet fisheries, and as bycatch in other fisheries such as in demersal and drift gittnet, trammel net a-nd long line fisheries.
SIZE AT FIRST MATURITY OF THE BLUE SPOTTED MASKRAY, Neotrygon kuhli lN INDONESIAN, WATERS Fahmi, Fahmi; Adrim, Mohammad; Dharmadi, Dharmadi
Indonesian Fisheries Research Journal Vol 15, No 2 (2009): (December 2009)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (6457.414 KB) | DOI: 10.15578/ifrj.15.2.2009.29-35

Abstract

The biue spotted maskray, Neotrygon kuhtii is the most common rays occurred in Indonesian waters. This species is often caught as bycatch in trawl fisheries targeting demersal fishes and shrimps.
CATCH COMPOSITION AND SOME BIOLOGICAL ASPECTS OF SHARKS IN WESTERN SUMATERA WATERS OF INDONESIA Dharmadi, Dharmadi; Mahiswara, Mahiswara; Kasim, Kamaluddin
Indonesian Fisheries Research Journal Vol 22, No 2 (2016): (December, 2016)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (412.16 KB) | DOI: 10.15578/ifrj.22.2.2016.99-108

Abstract

This study was conducted in western Sumatera and since October 2013 to June 2014. The sampling locations in Banda Aceh and Sibolga-North Sumatera which were the largest base of fisheries in western Sumatera region. Shark landing recorded by enumerators was used  as sampling data daily . This research aim to describ sex ratio, size composition, catch composition of sharks, and length at first maturity. In Banda Aceh, the sharks as target fish collected by  sorting the bycatch from tuna longlines and tuna handlines. In Sibolga, sharks  is bycatch from fish net, bottom gillnet and purse seine. Overall, there were 20 species of shark caught in west Indian Ocean and landed at those fish landing sites, dominated by Spot tail shark (23%) and Silky shark (13%), whereas Hammerhead shark contributed about 10% and  Oceanic whitetip shark was only less than 1%. Almost of Spot tail shark, Silky shark, and Scalloped hammerhead that caught in that area were  immature, while for the almost part of Tiger shark and Pelagic thresher were  matured. The sex ratios for Spot tail shark, Silky shark, Tiger shark, Pelagic thresher, and Scalloped hammerhead caught and landed at Lampulo and Sibolga fish landing sites were not balance. The length at first maturity for Spot tail shark was Lm=87,1 cm and Lm = 213,2 cm total length for Tiger shark. 
SHARK LONGLINE FISHERY IN TANJUNGLUAR-EAST LOMBOK Dharmadi, Dharmadi; Faizah, Ria; Sadiyah, Lilis
Indonesian Fisheries Research Journal Vol 19, No 1 (2013): (June 2013)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4131.081 KB) | DOI: 10.15578/ifrj.19.1.2013.39-46

Abstract

Studies on artisanal shark fisheries in Tanjungluar - East Lombok were conducted during the year 2001-2011 (except in 2003 and 2007). A sampling method called “rapid market survey” method was employed to collect catch data from surface and bottom longlines fishing, rapidly. Biological data and fisheries data were collected during survey. Catch data for shark were also obtained from daily records filled by TPI officers in Tanjungluar between 2009 and 2010. The results showed that sharklongline fishing was conducted every month. The trend of shark catches relates to the number of fishing vessels, fishing ground, and weather conditions at sea. The period between July and September is a transitional season from East to West seasons. During this season, the wind strength is weakened and a good fishing season for the fishers. The lowest catch occurs in January (1.06 tonnes) and the highest catch in September with the total catch of 24.6 tonnes. Sharks caught by surface longline were dominated by Silky shark, Carcharhinus falciformis (40-90%) with the size range of 100-125 cm. The catch of bottom longline was mostly consisting of fish in mature condition that dominated by Grey reef shark (Carcharhinus amblyrhynchos), Common black tip shark (C. limbatus), Spot tail shark (C. sorrah), and Scalloped hammerhead shark (Sphyrna lewini), with the size range of 125-200 cm, 170- 250 cm, 100-150 cm, and 170-300 cm, respectively. Surface longline fishing occurs in the offshore waters in depth more than 200 m to 3000 m, whereas bottom longline fishing is operated at a depth of 50-100 m around islands.
FREKUENSI PEMUNCULAN, TINGKAH LAKU, DAN DISTRIBUSI MAMALIA LAUT DI LAUT SAWU, NUSA TENGGARA TIMUR Dharmadi, Dharmadi; Faizah, Ria; Wiadnyana, Ngurah Nyoman
BAWAL Widya Riset Perikanan Tangkap Vol 3, No 3 (2010): (Desember 2010)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (619.274 KB) | DOI: 10.15578/bawal.3.3.2010.209-216

Abstract

Penelitian mamalia laut dilakukan pada bulan Juli dan Desember tahun 2005 di perairan Laut Sawu, Nusa Tenggara Timur. Tujuan penelitian ini untuk mengetahui tingkah laku, frekuensi pemunculan, dan pola penyebaran mamalia laut. Metode survei menggunakan garis transek dengan pola zig-zag dan dilengkapi dua pengamat (double observer). Delapan spesies mamalia laut yang terdiri atas paus dan lumba-lumba berhasil diidentifikasi, yaitu ikan paus sperma (Physetermacrocephalus), paus pilot (Globicephala macrorhynchus), paus pembunuh kerdil (Feresa attenuata), paus pembunuh (Pseudorca crasidens), lumba-lumba paruh panjang (Stenella longirostris), lumbalumba botol (Stenella attenuata), lumba-lumba fraser (Lagenodelphis hosei), dan lumba-lumba hidung botol (Tursiop truncatus). Tingkah laku mamalia laut yang teridentifikasi selama pengamatan adalah berburu mangsa, melompat ke atas permukaan air, dan berenang menuju arah tertentu. Frekuensi pemunculan tertinggi dilakukan oleh Stenella longirostris yaitu 245 kali atau 84,1% kehadiran pada bulan Juli dan 994 kali atau 60,8% kehadiran pada bulan Desember 2005. Distribusi mamalia laut di Laut Sawu sebagian besar terkonsentrasi di sekitar perairan Lembata, Pantar, danAlor, Nusa Tenggara Timur yang juga didominansi oleh Stenella longirostris. Study on mamals was conducted in the Sawu Sea, East Nusa Tenggara on July and December 2005. The objectives of these research are to study the sighting frequency and the distribution patterns of marine mammals. Survey was conducted using line transect with zig-zag patern that equiped by two observer. Eight species of cetacean, namely sperm whale (Physetermacrocephalus), short fin pilot whale (Globicephala macrorhynchus), false killer whale (Pseudorca crasidens), pigmy killer whale (Feresa attenuata), spinner dolphin (Stenella longirostris), spotted dolphin (Stenella attenuata), fraser’s dolphin (Lagenodelphis hosei), and bottlenose dolphin (Tursiops truncatus). The cetacean behavior during observation are hunting, forfeed jumping in the air, and travelling to certain direction. Stenella longirostris is the frequent observed species compared to the others, where 245 sightings (84,1%) on July and 994 sightings (60,8%) on December 2005. The cetacean distributed in the Lembata, Pantar, and Alor waters, East Nusa Tenggara was dominated by spinner dolphin (Stenella longirostris).
TINGKAT KEMATANGAN KELAMIN DAN FREKUENSI PANJANG PARI GITAR (Rhinobatus sp.1 dan Rhinobatus sp. 2) Dharmadi, Dharmadi; Fahmi, Fahmi
BAWAL Widya Riset Perikanan Tangkap Vol 1, No 1 (2006): (April 2006)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (767.887 KB) | DOI: 10.15578/bawal.1.1.2006.31-35

Abstract

Pari gitar ( (Rhinobatus sp.) merupakan salah satu jenis pari yang mempunyai nilai ekonomb tinggi. Jenis pari ini sering tertangkap dengan alat tangkap jaring dasar, karena mereka hidup di dasar perairan yang berpasir. Penentuan kematangan jenis kelamin jantan dapat diketahui berdasarkan pada kondisi klasper, yang dikelompokan menjadi 3 tingkatan yaitu 1) klasper dalam kondisi lunak belum atau sedikit berisi zat kapur; 2) klasper berisi zat kapur dalam kondisi agak keras dan 3) klasPEr berisi penuh zat kaPur dalam kondisi keras. Ukuran panjang klasper berhubungan secara linier terhadap panjang tubuh pari gltar Sedangkan trekuensi panjang pari gitar berfluktuasi berdasarkan pada waktu dan Jenis kelamin.
KEMUNCULAN DAN TINGKAH LAKU PESUT (Orcaella brevirostris (Owen in Gray 1866) SEBAGAIMAMALIATERANCAMLANGKA DI PERAIRANKUBU RAYADANKAYONGUTARAKALIMANTAN BARAT Anggawangsa, Regi Fiji; Dharmadi, Dharmadi; Sulistyowati, Nunik
BAWAL Widya Riset Perikanan Tangkap Vol 6, No 2 (2014): (Agustus 2014)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (256.188 KB) | DOI: 10.15578/bawal.6.2.2014.63-68

Abstract

Pesut atau Irrawaddy dolphin (Orcaella brevirostris) merupakan salah satu spesies mamalia air yang populasinya semakin terancam. Sedikitnya informasi keberadaan pesut di Kalimantan Barat, menyebabkan upaya konservasi dan pengelolaannya belum optimal. Tulisan ini bertujuan untuk mengetahui keberadaan dan tingkah laku pesut yang terdapat di perairan Kubu Raya dan Kayong Utara, Kalimantan Barat. Kegiatan pengamatan menggunakan metode jelajah dengan bantuan teropong binokuler dilaksanakan pada bulan April2013. Selama pengamatan hanya diketahui terdapat satu kelompok pesut sebanyak 4-6 individu yang terdiri dari pesut muda dan dewasa. Kelompokan itu dijumpai di muara Sungai Bumbun pada kedalamanan perairan 11 meter. Tingkah laku yang teramati menunjukkan gerombolan pesut umumnya memburu kelompokan ikan dan sesekali menyemburkan air dari blowhole nya. Berdasarkan ciri-ciri morfologi dan tingkah laku yang teramati serta kondisi lingkungan perairan setempat maka perairan di Kabupaten Kubu Raya dan Kabupaten Kayong Utara yang terletak di Provinsi Kalimantan Barat diduga merupakan perairan yang potensial sebagai habitat pesut (Orcaella brevirostris).Irrawaddy dolphins (Orcaella brevirostris (Owen in Gray 1866)) is one of aquatic mammals species who populations are increasingly threatened. The lack information about population of Irrawaddy dolphins in West Kalimantan waters makes the conservation of this species and its management were still not optimized yet. This research aims to identify the characteristics and behavior of dolphins found in Kubu Raya and Kayong Utara waters of West Kalimantan. The observation was held on April 2013, exploring coastal waters and estuaries which are expected to be the habitats of Irrawaddy dolphins using binoculars. There are 4-6 individuals of Irrawaddy dolphin found at the mouth of Bumbun River. A group consist of young and adults dolphins at the depth of 11 meters. The observed behavior is chasing schooling fish and occasionally spitting water from his blowhole. Based on morphological character and fish behavior observed, and environmental condition parameters, indicated that the water surrounding of Kubu Raya and Kayong Utara District were potential habitat for Irrawaddy dolphins.
PEMANTAUAN STATUS POPULASI PESUT (Orcaella brevirostris) DI SUNGAI PELLA (DAERAH ALIRAN SUNGAI MAHAKAM), KALIMANTAN TIMUR Oktaviani, Dian; Aisyah, Aisyah; Dharmadi, Dharmadi
BAWAL Widya Riset Perikanan Tangkap Vol 1, No 6 (2007): (Desember 2007)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (544.889 KB) | DOI: 10.15578/bawal.1.6.2007.209-214

Abstract

Populasi pesut (Orcaella brevirostris) saat ini dikatakan mengalami penurunan setiap tahun dan dalam status terancam kepunahan. Sungai Pella merupakan sungai yang menghubungkan antara Danau Semayang dengan Sungai Mahakam dan dikenal sebagai tempat pesut beraktivitas sepertimencari makan dan bermain. Penelitian mengenai status monitoring populasi pesut dilakukan pada bulan September 2004 dan Oktober 2005. Metodologi yang digunakan yaitu purposif untuk penentuan lokasi dan penghitungan langsung populasi dengan analisis secara deskriptif. Lokasi penelitian diSungai Pella terletak pada posisi 116°33’03,0" BT 00°14’09,9" LS-116°33’55,2" BT 00°14’25,2" LS. Hasil penelitian menunjukkan populasi pesut yang muncul di Sungai Pella antara 2 sampai dengan 12 ekor. Status populasi pesut di Sungai Pella adalah tetap dibandingkan dengan penghitungan pada tahun 1999 dan 2002.
BEBERAPA JENIS CUCUT BOTOL (squalidae) YANG TERTANGKAP PANCING RAWAI DASAR DI PERAIRAN SAMUDERA HINDIA DAN ASPEK BIOLOGINYA Dharmadi, Dharmadi
BAWAL Widya Riset Perikanan Tangkap Vol 1, No 2 (2006): (Agustus 2006)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1237.255 KB) | DOI: 10.15578/bawal.1.2.2006.65-69

Abstract

Terdapat 9 jenis cucut botol yang tertangkap dengan pancing rawai dasar di perairan samudera Hindia yaitu Squalus sp 1; Squalus sp 1 b; Sgualus sp 2, Squalus sp 2b; Squalus sp 2c; Squalus sp 3: Squalus sp 3b; sgualus sp 4: dan squalus sp 4b; Nisbah kelamin cucut botol jantan dan betina 36.65 Sedangkan tingkat kematangan kelamin jantan cucut botol yang dijumpai dibedakan menjadi 3 kategori, yairu krasper yang belum bensi atau belum mengandung kapur (nol carsification), klasper yang telah berisr sebagian zat Kapur (full calsification).
ASPEK BIOLOGI DAN FLUKTUASI HASIL TANGKAPAN CUCUT TIKUSAN, (ALOPIAS PELAGICUS) DI SAMUDERA HINDIA Dharmadi, Dharmadi; Fahmi, Fahmi; Triharyuni, Setya
BAWAL Widya Riset Perikanan Tangkap Vol 4, No 3 (2012): (Desember 2012)
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Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (314.835 KB) | DOI: 10.15578/bawal.4.3.2012.131-139

Abstract

Cucut tikusan (Alopias pelagicus) merupakan salah satu spesies cucut yang habitatnya di perairan oseanik dan umumnya sering tertangkap dengan jaring insang tuna yang beroperasi di perairan Samudera Hindia. Penelitian ini dilakukan pada April 2002 sampai Desember 2007 di tempat pendaratan ikan Pelabuhan Perikanan Samudera Cilacap. Metode penelitian yang digunakan adalah dengan pengamatan langsung di lapangan dan pengumpulan data melalui enumerator. Hasil penelitian menunjukkan bahwa hubungan antara panjang total dengan panjang klasper bersifat logaritmik (R2 = 0,8694) dan berbeda nyata (P < 0,05). Hubungan antara panjang total dan panjang standar baik jantan dan betina bersifat linier masing-masing dengan nilai ( R2= 0,9803, dan R2=  0,9423). Frekuensi panjang terendah pada cucut tikusan jantan antara 150-170 cm (kelompok muda) dan antara 291-310 cm (kelompok dewasa). Frekuensi tertinggi terdapat pada ukuran antara 231-250 cm dan antara 251-270 cm. Pada cucut tikusan betina, frekuensi panjang terendah adalah 200-220 cm (kelompok muda) dan antara 321-340 cm (kelompok dewasa), dan tertinggi antara   261-280 cm.  Sedangkan rasio kelamin jantan dan betina cucut tikusan mendekati 1:1 (51% : 49%). Hasil tangkapan cucut tikusan selama enam tahun mengalami penurunan sebesar 34,9 %. Ada indikasi terjadi penurunan kelimpahan cucut tikusan di perairan Samudera Hindia. Pelagic thresher shark (Alopias pelagicus) is one of shark species that habitat in oceanic waters and are generally caught with gill nets of tuna fishing gear that operates in the Indian Ocean. This research was conducted in April 2002 until December 2007 at Cilacap fish landings. Research methodology with direct observation and data collection by enumerators. The results showed that the relationship between the total length and the clasper  length was logaritmic (R2 = 0,8694) and significant different (P<0,05). Relationship between the total length and the precaudal length of both male and female were linier (R2= 0,9803, dan R2=  0, 9423) respectively. Length frequency of male Alopias pelagicus was lowest between 150-170 cm total length (young group) and between 291-310 cm total length (adult group). The highest frequency contained in the size between 231-250 cm and between 251-270 cm. The lowest frequency of female Alopias pelagicus was 200-220 cm total length (young group) and between 321-340 cm total length (adult group), and the highest between 261-280 cm total length. While the sex ratio of male and female Alopias pelagicus aproximately 1: 1 (51%: 49%). The catches of species within six years decreased by 34.9%, this indicated that the abundance of Alopias pelagicus was decline in the Indian Ocean.