Establishing a DNA reference library for the identification of elasmobranchs in the Indian Ocean using Oxford Nanopore Sequencing

Elasmobranchs (sharks,chimeras and rays) play an important role within food webs in marine ecosystems. But these species face global declines due to overfishing, which is exacerbated by their slow growth rates, late maturation, and low fecundity. Elasmobranchs in Sri Lanka are captured by both target and bycatch fisheries. For more than half a century various authors have attempted to identify commercially and non-commercially important sharks in Sri Lanka (Amarasooriya and Dayaratne, 1994; De Bruin et al., 1995; De Silva, 1988, 1995; Mendis, 1954; Munro, 1955). According to Fernando, D., 2021, Sri Lanka is presently the largest silky shark catcher and the second largest Mobula ray catcher. Even though Sri Lanka gives legal protection for five shark species, the waters around Sri Lanka consist of many more shark and ray species listed as threatened in the IUCN Red List (over 100 sharks and rays have been confirmed in Sri Lanka and more than 70% are considered threatened). Data for many of these species is lacking in the present.Through this project, we focus on providing identification systems for elasmobranch species using novel technology (Oxford Nanopore Technology- MinION). This will support visual species identification (of whole specimens at landing sites and fins at points of export) but also enable the identification of products in domestic and international trade that cannot be visually identified (meat, oil, skin etc). Also, data gathered from this project enable accurate identification of the shark & ray tissue for biodiversity indexing and resolve phylogenetic relationships among multiple taxa.