DNA barcoding reveals threatened and protected elasmobranchs in Tanzanian fish markets

Abstract

Western Indian Ocean countries have banned elasmobranch finning and enacted legislation to protect endangered elasmobranchs, however finned and morphologically deformed specimens are still landed and traded on Tanzanian fish markets. Such specimens are difficult to identify morphologically, and it is possible that protected elasmobranchs are among these. This study used DNA barcoding to uncover protected elasmobranchs in 102 specimens traded on Tanzanian fish markets. The sampled specimens revealed 23 elasmobranch species, 12 of which (52.1 %) were classified as endangered (EN) or critically endangered (CR) on the IUCN Red List. Three of the identified species (great hammerhead Sphyrna mokarran, oceanic whitetip shark Carcharhinus longimanus, and pelagic thresher Alopias pelagicus) are protected by Tanzanian laws. Hence, it is advised that steps be taken to strengthen law enforcement at landing sites and fish markets in the country. Furthermore, the Third Schedule of Fisheries (Amendment) Regulations of 2009 should be updated to include 11 EN and CR elasmobranchs that are not on the list. Additionally, national and regional elasmobranch conservation plans should be developed to prevent the exploitation of endangered elasmobranchs.