BIO PALEMBANICA
Vol 3 No 1 (2026): Bio Palembanica

Mortality Records of the Irrawaddy Dolphin Orcaella brevirostris (Artiodactyla: Delphinidae) in Sumatra and Java

Nur Rachman (Daemeter Consulting, Bogor)
Muhammad Sayidina Ali (Daemeter Consulting, Bogor)
Randi Syafutra (Department of Natural Resources Conservation, Muhammadiyah University of Bangka Belitung)
Surianto Effendi (Daemeter Consulting, Bogor)
Sahat Aritonang (Daemeter Consulting, Bogor)
Muhammad Iqbal (Department of Biology, Universitas Indo Global Mandiri)



Article Info

Publish Date
30 Jun 2026

Abstract

Indonesia is a global biodiversity hotspot, yet aquatic mammals remain understudied, particularly in coastal and estuarine ecosystems. The Irrawaddy Dolphin Orcaella brevirostris inhabits these environments and is highly exposed to anthropogenic pressures. This study compiles mortality records of O. brevirostris in Sumatra and Java using published papers, media reports and citizen science data. A total of 24 records (2011–2025) were documented, with most concentrated along the eastern coast of Sumatra. Of the 24 documented mortality records of O. brevirostris in Sumatra and Java (2011–2025), unknown causes accounted for the majority of deaths (14 records, 58.3%). Fishing gear entanglement was the second most common cause (7 records, 29.2%), representing the primary identified anthropogenic threat. The remaining mortalities were each attributed to suspected poaching, strong monsoon currents, and extreme weather (1 record each, 4.2%). Reported body lengths ranged from 90 to 225 cm and weights from 80 to 150 kg. Both juvenile and adult individuals were affected, with adult mortality raising concerns for population viability. These findings highlight critical risk zones and the need for improved monitoring and conservation measures.

Copyrights © 2026






Journal Info

Abbrev

biopalembanica

Publisher

Subject

Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Immunology & microbiology

Description

Bio Palembanica come from Bio and Palembanica. Bio refer to Biology, and Palembanica. Palembanica come from Latin for Palembang, a location in Southern Sumatra (recently capital city of South Sumatra). Few species are namely with palembanica, such as Intsia palembanica (Fabaceae), Shorea palembanica ...