Catch Composition and Some Biological Aspects of Sharks in Western Sumatera Waters of Indonesia

Abstract

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.

The Economic Value of Shark and Ray Tourism in Indonesia and Its Role in Delivering Conservation Outcomes

“…Secondly, the primary users/exploiters of sharks (i.e., shark fishers) are spatially separated from the areas where shark and ray tourism is taking place. For example, known shark fishing and trade hotspots in Indonesia include Cilacap (Central Java), Muara Baru (Jakarta) and Tanjung Luar (Lombok, West Nusa Tenggara), Aceh, South Halmahera, and Sibolga (Blaber et al, 2009;Dharmadi et al, 2017;Booth et al, 2018;Ichsan et al, 2019a,b; also see Figure 1), which are outside of the key tourism hotspots identified in this study. This is supported by the finding that only one fisher in the surveyed local communities identified as a shark fisher, and dive operators reported employing only three former shark fishers.…”

First photographic inland record of blacktip reef sharks Carcharhinus melanopterus (Carcharhiniformes: Carcharhinidae) in Indonesian waters

“…This record of C. melanopterus in freshwater habitat near Sentani lake is rare and constitutes the first inland record in Indonesian waters. There are other records of C. melanopterus found elsewhere in Indonesia but none of these records are from freshwater (White 2007;Dharmadi et al 2016).…”

“…Carcharhinus melanopterus and C. leucas are close relatives and may have similar physiological capabilities and behavioural characteristics. However, although there are many reports of C. melanopterus elsewhere in Indonesia none of them have been in freshwater (White, 2007;Last et al 2010, Dharmadi et al 2016. Knip et al (2011) found pigeye shark C. amboinensis juveniles respond to seasonal freshwater inflow and that may also be true for juvenile C. melanopterus.…”

“…The blacktip reef shark Carcharhinus melanopterus (Quoy & Gaimard, 1824) is a medium-sized elasmobranch of whaler shark (family Carcharhinidae) that reportedly grows up to 1.5 m (total length) and occurs throughout the tropics from the Red and Indian Sea (Chin et al 2013b). In Indonesia, the species has been recorded from Sumatra, Kalimantan, Java, Bali, Sulawesi, Lombok, West Timor and Papua (White 2007;Last et al 2010;Dharmadi et al 2016). The C. melanopterus inhabits very shallow water on coral reefs and reef flats, also near reef drop offs, rarely close to offshore (Compagno et al 2005;Ebert et al 2013).…”

Komposisi Jenis, Hasil Tangkapan Per Upaya, Musim Dan Daerah Penangkapan Ikan Hiu Di Perairan Samudera Hindia Selatan Jawa

“…Penelitian tentang perikanan hiu telah banyak dilakukan di Indonesia terutama di perairan Samudera Hindia (WPP 573) diantaranya Palabuhanratu, Cilacap dan Nusa Tenggara Barat (Dharmadi et al, 2008;Arrum et al, 2016;Chodrijah et al, 2017;Sentosa et al, 2016), Laut Jawa (WPP 712) (Dharmadi et al, 2010), Barat Sumatera (WPP 572) (Dharmadi et al, 2016). Ikan hiu awalnya merupakan hasil tangkapan sampingan (HTS) atau bycatch, namun beberapa tahun terakhir dengan adanya permintaan ikan hiu yang semakin meningkat maka ikan hiu menjadi target penangkapan utama khususnya di sepanjang Selatan Jawa.…”