Indonesian Manta Ray Habitat Use disturbance to this threatened species by tourism, regulations for the number of boats and interactions, especially during key reproductive times should be considered. Further, strict fishing regulation in the area is recommended as fishing gear entanglement was identified as a threat to this population.
International concern is growing with regard to the sustainability of manta and devil ray (collectively mobulids) fisheries as demand for mobulid products has increased in international markets over the last decade. While Indonesia has been reported to be one of the worlds’ top three catchers of mobulid rays, detailed information on these fisheries and the status of Indonesian mobulid populations are lacking. Through collection of historical and recent mobuild fisheries data from published and unpublished sources, this study aimed to identify trends in abundance of Indonesian manta and devil rays and explore socio-economic factors and incentives associated with mobulid fisheries. Comparison of catches from 2001-5 to the most recent data from 2013-14 revealed dramatic declines in mobulid landings over the study period of 64% at Cilacap, 75% at Lamakera, and 94% at Tanjung Luar. The largest declines were observed for Manta spp. and the two large devil rays, Mobula tarapacana and Mobula japanica. Anecdotal reports indicated that catches had declined substantially at three additional sites and local extirpations are strongly suspected to have occurred at three locations. A lack of data on the population ecology of Indonesia’s mobulids makes it difficult to determine whether natural fluctuations may be playing a part in the declining catch rates. However, mobulid life history traits, including low reproductive rates and late age of sexual maturation, indicate that fishing pressure is likely the primary driver in these declines. Interviews in Lamakera, a community which depends on income from its targeted mobulid fishery, suggest that programs focused on education, training and infrastructure development to enable shifts to sustainable livelihood alternatives are likely to offer the most successful path to long-term conservation and management of manta and devil rays, while simultaneously yielding economic and social benefits to fishing communities.
Indonesia has a very diverse shark and ray fauna and is the largest chondrichthyan fisheries in the world. Most Cilacap (32 species), and at Pelabuhan Ratu (27 species). A total of 55 species of rays belonging to one oi 12 families were recordeci from the same landing sites^ The most speciose and commonly recorded family of rays was the Dasyatidae, which was represented by 28 species, and contributed 65.2% to the total number of chondrichthyan individuals recorded. The most abundant dasyatids recorded were the smaller ray species Neotrygon kuhlii, Dasyatis zugei, and Himantura walga' and the larger species Himantura gerrardi and Himantura fal which collectiveiy comprised 57 8% of the total number of all chondrichthyans ianded.
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 shark<br />longline 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 (<em>Carcharhinus amblyrhynchos</em>), Common black tip shark (<em>C. limbatus</em>), Spot tail shark (<em>C. sorrah</em>), and Scalloped hammerhead shark (<em>Sphyrna lewini</em>), 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.
This paper reviews the biodiversity and habitat preferences of living sharks in the Southeast Asian region accumulated from published literatures including journals, books, proceedings, unpublished technical papers, and technical reports as well as authors’ knowledge and experiences working in this field. A total of 196 species of sharks from nine orders and 30 families have been recorded inhabiting from fresh water to deep ocean in this region. Indonesia recorded the highest diversity with 114 species from 27 families followed by the Philippines with 96 species (27 families), Thailand 76 species (21 families), Vietnam 70 species (23 families), Malaysia 68 species (19 families), Myanmar 64 species (19 families), Brunei Darussalam 45 species (15 families), and Cambodia with 26 species from 10 families. Many species still need to be confirmed and are most probably new species. In term of habitat preferences, 83 species of sharks (42.3%) inhabit continental/insular shelves (SHL) followed by continental/insular slopes (SLO) with 48 species (24.5%), shelf to slope (SHS) with 26 species (13.3%), and shelf to oceanic (SHO) with 16 species (8.2%). Only nine species (4.6%) inhabit oceanic and six species (4%) obligate freshwater and euryhaline freshwater/shelves.
ABTRACTThis 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.
Cucut lanjaman (C. falciformis) merupakan salah satu jenis cucut dari famili Carcharhinidae yang umum tertangkap di perairan Samudera Hindia dengan alat tangkap rawai cucut, rawai tuna, dan jaring insang tuna. Penelitian ini dilakukan pada bulan April 2001 sampai dengan Desember 2004 di beberapa tempat pendaratan ikan dan pasar ikan di Pelabuhanratu, Cilacap, Kedonganan-Bali, dan Tanjung Luar-Lombok. Hasil penelitian menunjukkan bahwa hubungan antara panjang total dengan panjang klasper terlihat eksponensial, dengan nilai R2=0,8218 (untuk klasper yang belum berisi zat kapur), dan nilai R2=0,8197 (untuk klasper yang sebagian berisi zat kapur), dan linier dengan nilai R2=0,7529 (untuk klasper yang penuh dengan zat kapur). Korelasi antara panjang klasper dengan panjang total tubuh cucut semakin kecil dengan semakin bertambah zat kapur dalam klasper. Frekuensi panjang terendah pada cucut lanjaman betina antara 51 sampai dengan 60 cm dan 241 sampai dengan 250 cm dan frekuensi panjang tertinggi antara 181 sampai dengan 190 cm. Pada cucut lanjaman jantan, frekuensi panjang terendah 251 sampai dengan 260 cm dan tertinggi antara 181 sampai dengan 190 cm. Sedangkan nisbah kelamin jantan dan betina cucut lanjaman mendekati 1:1 (51:49%). Nilai perbandingan nisbah kelamin suatu spesies dapat disebabkan oleh ketersediaan ikan dan selektivitas alat tangkap. Silky shark (C. falciformis) is one of the family Carcharhinidae community caught by shark longlin from, drift tuna long line and drift gill net in the Indian Ocean. This study was conducted between April 2001 to December 2004 at some fish landing sites an or fish market i.e. Palabuhanratu, Cilacap, Kedonganan-Bali, and Tanjung Luar Lombok. Results showed relationship between total length and clasper length was exponential (R2=0.8218), for not calcification clasper, and (R2=0.8197) for not full calcification clasper, and linier (R2=0.7529) for full calcification claspe . The correlation of clasper length and total length of silky shark tend to be smaller with in creasing calcificated content and clasper. The lowest length frequency of female silky shark was 51 to 60 cm and 241 to 250 cm, and the highest length frequency was 181 to 190 cm. Lowest length frequency of male silky shark was 251 to 260 cm and the highest was 181 to 190 cm. While sex ratio of male and female was mostly 1:1 (51: 49%). Variation of sex ratio occured due to the availability of fish and the selectivity of the fishing gear.
Hiu paus merupakan salah satu jenis hiu berukuran terbesar yang ada di dunia dan sudah masuk dalam daftar merah (Red List) untuk spesies terancam IUCN yaitu berstatus terancam punah (endangered). Untuk menjaga agar sumber daya hiu paus tetap terjamin populasinya, maka perlu adanya upaya pengelolaan untuk mendukung pelestarian spesies ini. Dalam makalah ini dibahas tentang strategi pemanfaatan dan penanganan hiu paus yang terdampar di perairan Indonesia. Metode penelitian yang digunakan adalah survei lapang dan wawancara yang dilakukan di Probolinggo dan Situbondo, Jawa Timur. Data dan informasi dihimpun dari penelusuran, dan penelahaan data dan informasi hasil penelitian serta laporan kegiatan yang terkait dengan hiu paus terdampar maupun keberadaannya di beberapa wilayah perairan di Indonesia. Hasil kajian menunjukkan bahwa terdapat enam wilayah perairan kemunculan hiu paus di Indonesia, baik yang menetap maupun yang tinggal sementara yaitu di perairan Teluk Cendrawasih, Talisayan, Kaimana, Teluk Gorontalo, Probolinggo, dan Banggai Kepulauan. Jumlah hiu paus yang berada di perairan Indonesia dan tersebar di beberapa wilayah perairan diperkirakan mencapai 253 ekor. dan teramati terbanyak berada di perairan Teluk Cendrawasih sebanyak 131 ekor. Kemunculan hiu paus maupun yang terdampar hampir terjadi setiap tahun dalam kondisi hidup terkadang keadaan mati. Koordinasi antara instansi terkait dan masyarakat dalam menangani dan menyelamatkan hiu paus yang terdampar maupun terjerat jaring saat ini sudah berjalan dengan baik. Terdapat 7 tahapan tata cara penanganan hiu paus terdampar dan ada 4 tahapan dalam rangka menunjang ekowisata hiu paus.Whale shark is one of the largest sharks in the world and on the red list IUCN for endangered species. To ensure that the population of whale sharks remains guaranteed, management efforts are needed to support the conservation of this species. The utilization and handling strategy of the whale sharks that stranded down in several Indonesian waters should be discussed seriously. Field survey method was applied and interview was done in Probolinggo and Situbondo, East Java. Data and information were collected and had been analyzed as well as activities reported that related to whale sharks stranded and their presence in several territorial waters Indonesia waters. The results of the study showed that there were six Indonesia waters area in which whale sharks appeared, both permanent and temporary, namely in Cendrawasih Bay, Talisayan, Kaimana, Gorontalo, Probolinggo, and Banggai Islands. The whale shark number that found in several Indonesian waters had been estimated about 253 individuals and the highest number was found 131 in Cendrawasih Bay. The appearances of whale shark and stranded in Indonesian waters has been almost every year and found in living or in such cases been in dead conditions that trapped in the shallow area. Coordination between related agencies and the community to carry out and rescuing whale sharks stranded or entangled in nets, has been in good progress. There were 7 stages of procedures for handling stranded whale sharks and 4 stages in order to support the ecotourism activities that related with appearances of whale sharks.
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