September 2024

The Mobula Project Indonesia has embarked on a groundbreaking initiative to research mobula rays in the Sumatra region, an area rich in biodiversity and ecological significance. Sumatra, Indonesia's third-largest island and the sixth largest globally, spans approximately 473,481 square kilometers, home to around 53 million people. Its strategic geographic positioning, bordered by the Strait of Malacca to the east and the vast Indian Ocean to the west, presents a unique opportunity for marine research and conservation.

Sumatra's west coast is particularly noteworthy, with its rugged coastline fringed by clusters of small islands and bordered by the nutrient-rich Sumatra Trough. This region, teeming with life, serves as an ideal habitat for a diverse array of marine species, including the elusive mobula rays, which are of increasing interest to conservationists and researchers alike.

In the initial phase of this pioneering project, the Mobula Project Indonesia team conducted comprehensive surveys across several provinces in Sumatra, including North Sumatra, West Sumatra, and Lampung. The primary objective of this pilot survey was to assess the interactions between mobula rays and local fisheries—a crucial step in understanding the challenges and opportunities for the conservation of these species. Our team meticulously visited fishing ports to observe local activities, identify potential landing sites for mobula rays, and engage with local fishermen. Through these interviews, we gathered invaluable insights into fishing locations, catch types, fishing seasons, and any encounters with mobula rays. Additionally, we initiated collaborative discussions with local governments and academic institutions to build a robust network for future research.

Surveys in Sumatra fish markets © Mobula Project Indonesia

The contrast between the fisheries on Sumatra’s eastern and western coasts was striking. The eastern coast, dominated by purse seine operations targeting small pelagic fish, revealed minimal interaction with mobula rays during our observations at the Belawan fishing port. The rays encountered here were primarily basic species, such as wedgefish and members of the Dasyatidae family. This region, characterized by river estuaries and shallow seas, supports both large-scale fishing vessels and small-scale fisheries, primarily focused on crabs and small demersal fish.

In stark contrast, the western coast of Sumatra exhibited a more diverse and dynamic fisheries landscape. Our surveys in West Sumatra and Lampung uncovered a variety of fishing gears in use, including gill nets, lift nets, purse seines, longlines, and bottom nets. Notably, mobula rays—specifically Mobula mobular and Mobula thurstoni—were found as bycatch in gillnet operations. Tissue samples from these rays were collected for detailed analysis, marking a significant step in understanding the biological and ecological characteristics of these species. Local fishermen provided crucial information on fishing grounds, aiding in the participatory mapping efforts that will inform future studies. The mobula rays caught in these waters are primarily utilised locally, reflecting the deep connection between the local communities and their marine environment.

Mobula ray tissue sampling © Mobula Project Indonesia

The findings from this pilot survey underscore the urgent need for focused research and conservation efforts on Sumatra's west coast, where mobula rays frequently become entangled in gill nets and purse seine nets. Despite their significance, comprehensive data on mobula rays and other ray species remain scarce, particularly within the frameworks of local government management and conservation strategies. The challenge is further compounded by the presence of private fish landing sites, which complicates data collection and monitoring efforts.

To address these challenges and build on our initial findings, we are poised to collaborate with four leading universities: Bung Hatta University in West Sumatra, Bengkulu State University in Bengkulu, Andalas University, and the Lampung Fisheries Polytechnic in Lampung. This collaborative research will explore the biological, ecological, and socio-economic dimensions of mobula ray populations, creating a comprehensive understanding of their role in Sumatra’s marine ecosystems. Initial communications with these institutions have been promising, and we are proud to announce that the research will be supported by the Cyclone Grant, which will fund the associated costs.

Mobula ray found in a Sumatra fish market © Mobula Project Indonesia

This project represents a pivotal moment for mobula ray conservation in Indonesia. With continued support and collaboration, we can make significant strides in protecting these enigmatic creatures and ensuring the sustainability of the marine ecosystems they inhabit. We extend our heartfelt thanks to the Cyclone members for their invaluable support in this project. Together, we have the power to create a lasting impact on the future of mobula rays in Sumatra.

Cyclone Grant 2024 Update 2 - Mobula Project Indonesia

September 2024

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