Arabian Sea humpback whale tagged off the coast of Oman crosses to India!
In November 2017, a research team led by the Environment Society of Oman (ESO) and Five Oceans Environmental Services placed a satellite tag on a humpback whale in the Gulf of Masirah, Oman. First observed, photographed, and biopsied close to the same site in October 2002, the whale was genetically determined to be a female, and was named Luban – the Arabic word for Frankincense – due to the tree-like pattern in the centre of her tail fluke. She was one of 14 whales to have been satellite tagged off the coast of Oman since 2014, of which only two were females. Tagging was supported through sponsorship from Renaissance Services SAOG. In the first three weeks following her tag deployment, it appeared that Luban would follow the pattern of previously tagged whales, that all remained in waters off the coast of Oman or Yemen. Around day 21, however, Luban began a journey that would captivate all of the members of the research team and all the members of the Arabian Sea Whale Network for the next several weeks. True to her name, Luban followed one of the ancient routes of the Frankinsense trade, crossing from Oman to the west coast of India, where she slowly made her way south and has been engaged in small-scale localized movements off the southernmost tip of India since late December.
Research teams on both sides of the Arabian Sea have been speculating as to the reasons behind this ocean crossing. Satellite imagery has revealed areas of high phytoplankton productivity along the west coast of India which is a potential indicator of where prey may be found, and interviews with fishers on the coast are detailing good landings of the one of the humpback’s favoured foods, sardines. However, given that the crossing occurred during the beginning of the population’s breeding season, some are speculating that she may have also been driven by a search for mating or calving grounds rather than feeding opportunities. By late December the overwhelming interest in Luban’s movements motivated a community of marine scientists along the west coast of India to collaborate and conduct fisher interviews as well as boat surveys to try and locate Luban or any other whales in the area, as well as to document the conditions around the area of her track. At the time of writing none of the parties have yet sighted Luban in Indian waters. However another team will begin surveys off the southern tip of India on January 31st to further investigate the waters where the telemetry data indicate she has spent the last month. It is hoped these surveys will feed into regional efforts to better understand the conservation status of this unique population of whales.
Arabian Sea humpback whales were designated as Endangered on the IUCN Red List of Threatened Species in 20081. At the time, reviewers considered the case for a Critically Endangered Status based on the very low numbers and threats documented off the coast of Oman, but decided that too little was known about the rest of the population’s suspected range. Questions have since remained as to whether whales taken on both sides of the Arabian Sea during illegal Soviet whaling operations in the 1960s2 represented a single management unit with frequent exchange, or two separate sub-populations isolated from each other. Luban’s crossing provides the first recent indication that there may be regular movement between Oman and other areas of the Arabian Sea, and increased efforts to collect opportunistic data from fishing, tourism and coast guard platforms in India and Pakistan indicate that humpback whales are still present on the Eastern side of the Arabian Sea.
The crossing provided extra excitement and motivation for researchers from a number of Arabian Sea humpback whale range states who met in Muscat from January 21-24th for a workshop focusing on the introduction of a new regional online data platform that will facilitate collaboration throughout the region. It has also confirmed that collaborative regional efforts, such as the recently approved Concerted Action under the Convention for Migratory Species are needed to effectively protect and manage this endangered population.
For more information consult Suaad al Harthi of the Environment Society of Oman: firstname.lastname@example.org, or Andrew Willson, of Five Oceans Environmental Services: email@example.com
- Minton, G. et al. Megaptera novaeangliae, Arabian Sea subpopulation. IUCN Red List of Threatened Species http://www.iucnredlist.org/details/132835 (2008).
- Mikhalev, Y. A. Humpback whales Megaptera novaeangliae in the Arabian Sea. Marine Ecology Progress Series 149, 13-21 (1997).