First Record of the Grey Reef Shark Carcharhinus amblyrhynchos, (Bleeker, 1856) (Carcharhiniformes: Carcharhinidae) from the Lakshadweep Sea, India
K.V. Aneesh Kumar 1, S. Paresh Khanolkar 2, P. Pravin 3, B. Meenakumari 4 & E.V. Radhakrishnan 5
1,2,3 Central Institute of Fisheries Technology, Matsyapuri P.O, Willington Island, Cochin, Kerala 682029, India
4 Indian Council of Agricultural Research, Krishi Anusandhan Bhavan-II, New Delhi 110012, India
5 Central Marine Fisheries Research Institute, Cochin, Kerala 682018, India
1 firstname.lastname@example.org (corresponding author), 2 email@example.com, 3 firstname.lastname@example.org, 4 email@example.com, 5 firstname.lastname@example.org
Grey Reef Shark Carcharhinus amblyrhynchos (Carcharhiniformes: Carcharhinidae) is a widely distributed requiem shark in the Pacific Ocean, and has an extensively scattered distribution in the Indian Ocean (Compagno 1984; William 2006). Indian elasmobranch fishery is one of the largest in the world (Vannuccini 1999) but information available on this species is very scanty (Raje et al. 2007). Pillai & Parakal (2000) and Joshi et al. (2008) have reported the presence of C. amblyrhynchos landings from Indian waters. Grey Reef Shark is a typical ‘reef shark’, found in clear tropical waters often from 10–50 m around coral reefs, in shallow water near coral slopes of islands and continents particularly near drop-offs, passes of fringing reefs and relatively common in atolls (Wetherbee et al. 1997; Economakis & Lobel 1998). The IUCN Red List of Threatened Animals categorizes C. amblyrhynchos as Near Threatened (Smale 2009), possibly due to its restricted habitat, site fidelity, inshore distribution, small litter size, and relatively late age at maturity, along with increasing fishing pressure.
Information available on the diversity and abundance of carcharhinid sharks in Indian waters is very meager though they contribute a major portion of the fishery. No scientific information is available on the presence of Grey Reef Shark in Lakshadweep waters which are known for coral reef biodiversity. In this paper, evidence for the occurrence of C. amblyrhynchos in Lakshadweep Sea is presented.
A female Grey Reef Shark C. amblyrhynchos was landed by fishermen from longline operation off Agatti Island in Lakshadweep Sea on 25 November 2010 (Image 1). The shark was caught by 3.4 Sun Japanese tuna hook and the location of capture was recorded as 10047’N & 72009’E (Image 2). The morphometric measurements of the shark were made to the nearest millimeter and weight was measured to the nearest gram. The species identification was based on Compagno (1984).
Results and Discussion
The morphometric measurements of the specimen are given in Table 1. The total length (TL) of the specimen was 126cm and standard length (SL) was 106cm. The Grey Reef Shark is a moderately stocky species, distributed in the coastal and pelagic waters of Indo-Pacific. Carcharhinus amblyrhynchos can be identified by the following characters: dusky grey color above and white below; first dorsal fin irregularly to prominently white edged (Image 3); posterior margin of the caudal fin with a conspicuous broad black margin; pectoral, second dorsal, anal and pelvic fins with blackish or dusky tips and prominent blackish margin (Image 4). The First dorsal fin is moderately large and semifalcate with a narrowly pointed apex. Second dorsal fin is moderately large and high. Pectoral fins falcate. Snout fairly long and broadly rounded. Eyes are round and fairly large. Upper labial furrows short and inconspicuous. Inter dorsal ridge absent. Upper teeth are narrow and serrated (Image 5). The species inhabits continental and insular shelves preferably on coral reefs and in shallow lagoons. The area from where the specimen is reported was near the coral ridge in Lakshadweep Sea. Present record is the first report of Carcharhinus amblyrhynchos from the Lakshadweep Archipelago.
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