Identifying nursery habitats and determining life history of Guitarfish in Sri Lanka

  • Rays & Skates
  • Sharks
Years funded
  • 2021
  • Active
Project types
  • Conservation
  • Research
  • Blue Resources Trust

Gobiraj is the lead researcher for the Blue Resources Trust’s “Sri Lanka Elasmobranch Project” for the country’s north and east coasts. To understand the scale and composition of Sri Lanka’s shark and ray fisheries, he collects baseline data in the form of identification photos, as well as a host of other measurements, and gathers tissue samples for genetic and stable isotope analysis. Gobiraj also speaks to local fishers to understand the type of fishing gear used and the catch location. He aims to use his project’s insights to help shape policy, and better protect sharks and rays across the region.

Identifying nursery habitats and determining life history of Guitarfish in Sri Lanka

Gobiraj Ramajeyam

Project leader
About the project leader

I am a young researcher in the field of fisheries science and I have a passion for marine biology and ecology, conservation and fisheries management in Sri Lanka. Unfortunately, I had no interaction with the marine environment until I was 20, although in those days I enjoyed seafood very much. I first got an opportunity to study marine biology and fisheries science when I embarked on my Bachelor’s degree in 2012. I became fascinated by the marine environment and the organisms that live in it. At the same time, I learned that ocean resources are not infinite but are being...

Project details

Identifying potential nursery habitats and determining life history of the Critically Endangered guitarfish

Key objective

This project aims to fill the knowledge gap on life-history parameters of sharpnose guitarfish (Glaucostegus granulatus) through the landing site data collection and detailed biological studies. Identify potential nursery habitats near the Mathagal region (Northern Sri Lanka).

Why is this important

Sharpnose guitarfish are a Critically Endangered benthic, coastal species with a limited distribution in the Northern Indian Ocean. They are impacted heavily by coastal fisheries and the lack of available data for this species is making it challenging to effectively manage them. This study addresses these issues and provides the first comprehensive baseline data to help conserve them and enable their recovery to fulfil their functional role in the ecosystem.


The global IUCN Red List of threatened species reveals that sawfishes, wedgefishes, and guitarfishes are amongst the most threatened marine fishes. Over 70% of guitarfish are either threatened or Data Deficient, including sharpnose guitarfish, which has a geographical distribution restricted to the Northern Indian Ocean region where it is estimated that >80% of their population has declined. Urgent action is needed to conserve sharpnose guitarfish and other rhino rays and their habitats, but the lack of species-specific information makes effective management action challenging.   Since August 2017, Blue Resources Trust (BRT) conducted over 900 days of survey and 300 fisheries dependent questionnaires on Rhinopristiformes around Sri Lanka which revealed that Mathagal (in the north) is the only place where sharpnose guitarfish (Glaucostegus granulatus) are frequently recorded (80% of survey days). More importantly, 25% of landed specimens were juveniles, indicating the potential for nursery habitats. Results also showed that >50% (24 species) of the species recorded in the north are present at Mathagal (9°47’54.3″N, 79°57’28.5″E) and it is a key site for some priority species, such as sharpnose guitarfish (Critically Endangered) and longheaded eagle ray (Endangered).  Since elasmobranch nurseries are where females lay eggs or give birth to their young, and where juveniles spend their early stages of life, the conservation of such habitats are essential to provide nutrition and protection and reduce the early mortality of young individuals. This proposed project will provide comprehensive life history data for sharpnose guitarfish and identify potential nursery habitats to develop effective management interventions.

Aims & objectives
  • To fill the gap between Sri Lankan sharks and rays fisheries by continuous landing site data with a special focus on Sharpnose guitarfish and supporting the management and conservation of sharks, rays and shark-like rays.
  • Identify potential nursery habitats near the Mathagal region (northern Sri Lanka) by using GPS units given by selected fishers and detailed study on the life history of Sharpnose guitarfish.  Results will be published and used to inform management recommendations and support stock assessments.