New records of sharks (Elasmobranchii) from the Andaman and Nicobar Archipelago in India with notes on current checklists.

Zoya Tyabji,Rima Jabado,Dipani Sutaria

doi:10.3897/bdj.6.e28593

Abstract

The diversity of sharks occurring off the Andaman and Nicobar Archipelago in India has received increased attention in recent years. Yet, available checklists are out of date, often with inaccurate information and a number of commercially important species have not been documented through research and fish landing surveys. Here we report on shark species examined during fish landing surveys conducted from January 2017 to April 2018. Records of twelve previously unreported species from the archipelago are presented and include the bignose shark (Carcharhinus altimus), pigeye shark (Carcharhinus amboinensis), bull shark (Carcharhinus leucas), snaggletooth shark (Hemipristis elongata), slender weasel shark (Paragaleus randalli), Arabian smoothhound shark (Mustelus mosis), Indonesian houndshark (Hemitriakis indroyonoi), sand tiger shark (Carcharias taurus), Indonesian bambooshark (Chiloscyllium hasseltii), tawny nurse shark (Nebrius ferrugineus), dwarf gulper shark (Centrophorus atromarginatus), and the Indonesian shortsnout spurdog (Squalus hemipinnis). These records increase the reported shark species for the archipelago from 47 to 59 and for India from 114 to 116. Additionally, a size extension in the total length of C. hasseltii by 27 cm and of P. randalli by 8 cm is reported. Owing to the bio-geographical location of these islands, species diversity around the archipelago is unique and appears to overlap with that of southeast Asia. With increasing reports of over-exploitation and the operation of a targeted shark fishery by distant water fleets in these waters, the limited information on shark diversity from this region is of concern. Systematic and long-term monitoring of catches, combined with accurate species identification, is crucial to provide information on management measures.

Highlights

Available checklists are out of date, often with inaccurate information and a number of commercially important species have not been documented through research and fish landing surveys
We report on shark species examined during fish landing surveys conducted from January 2017 to April 2018
CARCHARHINIFORMES - CARCHARHINIDAE - Carcharhinus altimus (Springer, 1950) From March 2017 to January 2018, three males and one female bignose shark Carcharhinus altimus (Fig. 2) were landed ranging in size from 90 cm to 237.5 cm total length (TL) with weights ranging from 2 kg to 93 kg

Summary

Introduction

The waters of India harbour an estimated 114 shark species (Akhilesh et al 2014, Sutaria et al 2015) from more than 500 globally known species (Weigmann 2016), of which 47 have been reported from the Andaman and Nicobar Archipelago (hereafter referred to as ‘the archipelago’) (Table 1, Rajan et al 2012, Varghese et al 2015, Rajan et al 2016, Pradeep et al 2017a, Pradeep et al 2017b). Large gaps remain in our understanding of shark resources with little research focused on species diversity across biogeographic zones, biology, stock structure and their socio-economic value (Rajan et al 2016). Such information, combined with accurate species identification, is crucial in order to provide information on and support future management measures (Elphick 2008, Simpfendorfer et al 2011). Carcharhinidae 4 Carcharhinus albimarginatus (Rüppell, 1837) 5 Carcharhinus altimus (Springer, 1950) 6 Carcharhinus amblyrhynchos (Bleeker, 1856).

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