DNA analysis of elasmobranch products originating from Bangladesh reveals unregulated elasmobranch fishery and trade on species of global conservation concern

Abstract

Trade involving elasmobranch products in Bangladesh is a four-decade-long practice in large scale and there is little understanding of its impact on species composition, population, and subsequent conservation. Capacity for monitoring and identification is lacking in landing and shark processing centres. A rapid survey and collection of tissue samples were performed in three landings and nine shark processing centres between 2016 and 2017 in the south-eastern coastal region of Bangladesh. Sequencing for a 707-bp fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene was used to assess the taxonomic status and species composition from 71 elasmobranch tissue samples collected from the shark processing centre only. Good quality COI sequences were obtained for 34 specimens representing 21 species—the majority of which are threatened with extinction. A total of ten species of sharks (Carcharhinus brevipinna, C. amboinensis, C. leucas, C. sorrah, C. amblyrhynchoides, Chiloscyllium burmensis, Galeocerdo cuvier, Rhincodon typus, Scoliodon laticaudus, and Sphyrna lewini), eleven species of rays (Aetomylaeus maculatus, Gymnura poecilura, Mobula mobular, M. kuhlii, Neotrygon indica, Pateobatis uarnacoides, Rhinoptera javanica, and R. jayakari), including three species of guitarfish (Glaucostegus granulatus, G. obtusus, and G. typus), were identified. Four species (14.7% of samples) were found to be listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in Appendix II. Sixteen species (59% of the specimens) were threatened with extinction according to IUCN Red List, whereas 41% were data deficient or not assessed. The results have important implications for the management of regional fisheries and the conservation of elasmobranchs as they 1) represent a preliminary understanding of elasmobranch diversity in trade; 2) depict a lack of awareness and monitoring; and 3) demonstrate a need for urgent monitoring and regulation of elasmobranch trade in Bangladesh.

Fishing and trade of devil rays (Mobula spp.) in the Bay of Bengal, Bangladesh: Insights from fishers’ knowledge

“…Within the devil ray distribution range, the Bay of Bengal offers high nutrient content, high biological productivity and oceanographic mixing, owing to upwelling, providing an ideal habitat for the predominantly pelagic planktivorous filter feeders such as devil rays (Somayajulu, Murty & Sarma, 2003; Smith et al, 2008; Adnet et al, 2012; Amaral et al, 2017). Two devil ray species have been reported within the Bangladesh region of the Bay, namely M. mobular (including former M. diabolus and M. japanica ) and M. kuhlii (Hoq, Haroon, & Hussain, 2011; Haque, Biswas & Latifa, 2018; Haque, Das & Biswas, 2019); M. hypostoma was also reported (presumably misidentified as this species only occurs in the Atlantic Ocean). Of these ray species, only M. mobular is protected in Bangladesh – under Schedule II of the Wildlife (Conservation and Security) Act, 2012 that protects 29 elasmobranch species under two schedules.…”

Evaluating artisanal fishing of globally threatened sharks and rays in the Bay of Bengal, Bangladesh

“…Before the field studies, an annotated checklist of all elasmobranchs reported from Bangladeshi waters was prepared from published documents found through a literature review [ 27 , 34 – 36 , 71 – 73 , 77 – 89 ].…”

“…Limited knowledge of elasmobranch diversity and their particular threats, habitat use, catch and bycatch trend, is leading to depletion of several species with global conservation concern in the Bay of Bengal region (e.g. Ganges shark, giant guitarfish, and wedgefish, sawfish amongst many) [ 13 , 24 , 27 , 28 ]. In addition, a historical baseline is lacking.…”

Sistema Integrado De Manejo De Fauna

“…The difficulty in correctly identifying cartilaginous fish is due to the fact that they arrive either already in processed state in markets, or only their fins are landed, making morphological identification impossible (VOOREN & KLIPPEL, 2006). Because of this, molecular markers have been widely applied to identify species exhibiting economic interest (WARD et al, 2005;KYLE & WILSON, 2007;SEVILLA et al, 2007;HOLMES et al, 2009;ASIS et al, 2014;BINEESH et al, 2015;FIELDS et al, 2015;SEMBIRING et al, 2015;VAN DER MERWE & GLEDHILL, 2015;CHUANG et al, 2016;STEINKE et al, 2017;ALMERÓN-SOUZA et al, 2018;FEITOSA et al, 2018;FERRETE et al, 2019;HAQUE et al, 2019;HELLBERG et al, 2019;MUTTAQIN et al, 2019;RODRIGUES-FILHO et al, 2020).…”

“…In this context, molecular methodologies, such as DNA Barcoding, may be applied to correctly identify different species, as they allow for better accuracy in elasmobranch identification (WARD et al, 2005, HOLMES et al, 2009ASIS et al, 2014;BINEESH et al, 2017;FIELDS et al, 2015;SEMBIRING et al, 2015;VAN DER MERWE & GLEDHILL, 2015;CHUANG et al, 2016;STEINKE et al, 2017;ALMERÓN-SOUZA et al, 2018;FEITOSA et al, 2018;FERRETE et al, 2019;HAQUE et al, 2019;HELLBERG et al, 2019;MUTTAQIN et al, 2019;RODRIGUES-FILHO et al, 2020). Thus, the DNA Barcode technique serves as a basic tool in the implementation of shark and ray management plans aiming at conservation actions.…”