On a knife-edge: saving sharpnose guitarfish in the Bay of Bengal
Little is known about how and where the Critically Endangered sharpnose guitarfish breeds and pups. But having this information, and feeding it into fisheries management plans, is essential to looking after its plummeting populations. Raha is on a mission to understand the breeding biology of this CITES-listed species because, although it is listed as a protected species in Bangladesh, the sharpnose guitarfish is still caught as a target and bycatch (incidental) species.
Durjoy Raha Antu
When I was eight, my parents took me to the coast for a holiday and I felt deeply attracted to the ocean, not least for its sheer size. In the latter stages of my school career I spent extra time studying zoology because I enjoyed it and this led to me studying for a degree in the subject. Once I became a student I spent a lot of time observing a wide range of creatures, from birds and butterflies to amphibians, nocturnal mammals and native fish. And yet I didn’t feel satisfied. In my third year of study...
Exploring the Reproductive Biology of Sharpnose guitarfish (Glaucostegus granulatus), from the Bay of Bengal, Bangladesh
The aim of this study is to draw up a conservation plan for the Critically Endangered sharpnose guitarfish by exploring its reproductive biology.
The sharpnose guitarfish Glaucostegus granulatus is considered globally Critically Endangered due to continued harvesting by artisanal and commercial fishers, despite local and international legislation. Little is known about the reproductive biology of this species in the Bay of Bengal and also globally. Information about its life history, especially its reproductive biology, could be used to make conservation management of the sharpnose guitarfish more sustainable.
Sharks and rays are at risk of extinction globally. Although the Bay of Bengal provides Bangladesh with vast marine and coastal resources, only 59 shark and ray species have been recorded so far in the country’s waters. Little is known about the elasmobranch groups of this region because of a lack of species-specific studies concerning their ecology, biology and habitats, and the trade in these species. The sharpnose guitarfish is a ray species belonging to the Rhinobatidae family and occurs in the northern Indian Ocean, from the Persian Gulf across the Bay of Bengal to Myanmar. On the verge of extinction because of continued harvesting by fishers, it has been declared Critically Endangered globally by the IUCN and is also listed on CITES Appendix II. In terms of Bangladesh’s Wildlife (Conservation and Security) Act, 2012, it is protected species. However, increased demand for its meat and fins, as well as other body parts for traditional medicine, has encouraged fishers to target the sharpnose guitarfish and to keep it when it is caught by accident, despite legislation. Moreover, the legislation has driven the trade in elasmobranchs out of the public eye.
Little is known about the reproductive biology of the sharpnose guitarfish both globally and in the Bay of Bengal. To address this knowledge gap, this study will document the species’ breeding biology, especially its reproductive cycle and fecundity, the length–weight ratio of males and females, their length at maturity and how long it takes them to reach maturity. The new knowledge we gain about its reproductive biology will help to draw up a sustainable conservation strategy for this globally threatened species.
- To determine the length–weight ratio of male and female sharpnose guitarfish and their length at maturity.
- To explore their reproductive cycle, fecundity and how long it takes them to mature.
- To understand the fishers’ perspective and raise awareness about the need to conserve this globally threatened species, and to draw up a conservation plan for it.