Short Communication: The presence of Bull shark Carcharhinus leucas (Elasmobranchii: Carcharhinidae) in the fresh waters of Sumatra, Indonesia

Abstract

Abstract. Hasan V, Widodo MS. 2020. Short Communication: The presence of Bull shark Carcharhinus leucas (Elasmobranchii: Carcharhinidae) in the fresh waters of Sumatra, Indonesia. Biodiversitas 21: 4433-4439. A single subadult specimen of Bull shark Carcharhinus leucas was photographed and captured by local fisherman using casting net on June 2020 in the upper Indragiri River, Riau Province, Indonesia. Carcharhinus leucas are one of only a few species of elasmobranchs that live in both marine and freshwater environments. This species currently listed as a near-threatened species based on the IUCN Red List Status. Singel specimen identified as C. leucas by the coloration of fresh specimen: white belly and greyish back, first dorsal fin high, tip of second dorsal and caudal fins black. Meristic characters measurement results as follows: total length 102 cm; fork length 86.3 cm; preanal length 65.1 cm; pre pelvic length 51.9 cm; pre pectoral length 22.5 cm; pre-orbital length 8.3 cm; head length 25 cm; pre-first dorsal length 29.4 cm; pre-second dorsal length 56 cm, and pre-caudal length 78.1 cm. This photo is considered as the third record from freshwaters of Sumatra after in the Batang Hari River, Jambi Province in 1997, and in the Musi River, South Sumatra Province in 2019. The photographic records indicate that a single specimen of C. leucas was found in the upper Indragiri River recorded more than 150 km inland. These results enhanced the understanding of C. leucas distribution in Sumatra freshwaters. Monitoring is needed to assess the possibility of the importance of the upper Indragiri River as a migration route, nursery, and growth ground of C. leucas. Studying small scale habitat use of C. leucas is challenged by their preferred habitats in freshwaters environments with fast-changing environmental conditions. Water conditions in the upper Indragiri River, namely salinity 0‰, temperature 25-27°C, dissolved oxygen 3.9-11.1 mg/l, are ideal for A. leucas habitat.

Short Communication: Presence of the vulnerable freshwater goby Sicyopus auxilimentus (Gobiidae, Sicydiinae) on Sangihe Island, Indonesia

“…Fish collection could be freely carried out without special permits, but the locals prohibit the use of nonenvironmentally friendly fishing gear (Kolding and van Zwieten 2014;Hasan and Widodo 2020). Four fish traps with a size of 90x90x40 cm 3 , made of wire and mesh with dimension of 3 cm were used in this study.…”

First photographic inland record of the Bull shark Carcharhinus leucas (müller and henle 1839) (Carcharhiniformes: Carcharhinidae) in Java, Indonesia

“…The evidence of C. leucas in Ciwulan River, Tasikmalaya District, West Java Province, is the first record in freshwaters of Java, and the fifth frehwater record beyond previous records from the archipelago of Indonesia (West-Papua, Borneo, Sumatra, and Celebes). Among other biological topics (Tony et al, 2020;Hasan et al, 2021c;Hasan et al, 2019a;Hasan et al, 2019b), the new record of near threatened fishes is an important contribution to raise an understanding of species biogeography Hasan and Widodo 2020;Hasan et al, 2021a;Hasan et al, 2021b;Gani et al, 2021). As reported in this paper, the new record of C. leucas will contribute to improve the knowledge of the species as it extends the distribution range of the species in Java.…”

First record of Longnose marbled whipray Fluvitrygon oxyrhyncha (Sauvage, 1878) (Myliobatiformes: Dasyatidae) in Malaysian waters

“…The evidence of F. oxyrhyncha in Pahang River, Kuala Lipis District, Pahang, is the first record in Malaysia, and the fourth record beyond previous records from the Southeast Asia regions (Thailand, Cambodia, and Indonesia) (Compagno 2016). Among other biological topics, the new record of rare non-marine elasmobranchs is an important contribution to raise an understanding of species diversity and biogeography (Hasan & Widodo 2020;Hasan & Islam 2020). As reported in this paper, the new record of F. oxyrhyncha will contribute to improve the knowledge of the species as it extends the distribution range of the species in Malaysia.…”