Arabian Sea Humpback Whales

Revised November 2020

Background and threats


Historical whaling records and 20 years of research conducted off the coast of Oman have revealed that the Arabian Sea humpback whale subpopulation is the only known population that does not undertake seasonal migrations between high-latitude feeding grounds and low-latitude areas for mating, calving and nursing. This unique, small subpopulation is endangered (Minton et al., 2008) and genetically isolated (Pomilla et al., 2014) and it may be found to represent a new subspecies diverged from other Indian Ocean populations roughly  70,000 years ago. In the 1960s at least 242 humpback whales were killed by illegal Soviet whaling activity off the coasts of Oman, Pakistan and India (Mikhalev, 1997).  Photo identification studies indicate that fewer than 100 individuals remain in the coastal waters of Oman (Minton et al., 2011). Photo identification, satellite tracking, and acoustic studies reveal a high degree of site fidelity and the regular occurrence of behaviour associated with both feeding and reproduction in two main study areas in Oman (Minton et al., 2011, Corkeron et al. 2011, , Willson et al., 2017).


Less is known about Arabian Sea humpback whales (ASHW) in other parts of the Arabian Sea, but emerging evidence collected through opportunistic observations, fisheries interviews, acoustic recordings, and fishing-crew based observers indicates that the population persists in areas where whales were taken in the 1960s off the coasts of Pakistan and India (e.g. Mahanty et al., 2015; Madhusudhana et al., 2018; Sutaria, 2019; Moazzam et al., 2020), and recent sightings extend into the Arabian Gulf (Dakteh et al. 2017).

Arabian Sea Humpback whale breaching off the coast of Oman. Photo credit: Daryl McDonald


There is also recent evidence from satellite tracking studies and photo identification that at least some individuals move between the coasts of Oman and India.

Threats throughout the region include:


  •  Entanglement in fishing gear: Fishing fleets, particularly those using drift or fixed gillnets, one of the gears most often associated with humpback whale entanglements elsewhere in the world (Johnson et al., 2005), are expanding throughout the Central, Western and Northern Indian Ocean (FAO, 2016). For example, gillnets, some as long as 26km in length, now account for over 40% of all tuna landings in the region, and although observer coverage for fisheries in the Arabian Sea is extremely limited, cetacean bycatch is likely to be significant. A recent study suggests that as many as 4.1 million small cetaceans may have been caught in tuna gillnet fisheries in the Indian Ocean  (Anderson et al., 2020). Credible estimates of the number of humpback whales entangled each year are unavailable, but 30—40% of the individuals photo-identified off Oman have entanglement wounds and scars and at least 11 individuals have been disentangled by rescue teams and fishermen in Omani coastal waters over the last 20 years (Minton et al., 2020).


  • Shipping, including ship strikes and disturbance from vessel noise: The region includes some of the world’s busiest shipping lanes, and new fast-ferry links are being planned and established throughout the region. Port construction and expansion is occurring in key humpback whale habitat off Oman, India and Pakistan. Other forms of coastal development represent increasing threats in a region where human populations are growing rapidly and infrastructure is expanding on a scale seen in few others parts of the world.


  • Oil and gas exploration and production carry threats of disturbance from seismic surveys and from construction and drilling noise, associated vessel traffic, and the potential for oil leaks and spills. Revenue from hydrocarbons continues to fuel development, human population growth and expansion of both into formerly remote parts of the region.



An Arabian Sea Humpback whale in Oman entirely entangled in a fishing net. This individual was released and has been resighted as recently as 2017. Photo credit: Robert Baldwin

Throughout the region, stakeholder awareness of the conservation status of Arabian Sea humpback whales and the many threats they face is low. Awareness-raising efforts in Oman, and more recently in other countries of the region, have nevertheless resulted in a significantly improved understanding among key stakeholders.  For example in India, at least two coastal states have put monitoring and research programmes in place as part of an ASHW National Species recovery program, and in Pakistan Marine Protected Areas have been created with the aim of protecting ASHW and other cetacean species. However, without further concrete efforts to mitigate the threats, the Arabian Sea humpback whale population is considered at high risk of extinction. The sub-population is designated as Endangered on the IUCN Red List of Threatened Species (Minton et al., 2008). The International Whaling Commission has expressed repeated concerns about its status (e.g. IWC, 2016), and it is one of only four humpback whale populations in the world still considered to be Endangered United States Endangered Species Act (NOAA, 2016).


Regional Collaboration for Conservation and Research


A workshop held in January 2015 addressed these pressing conservation concerns and led to the formation of the Arabian Sea Whale Network (ASWN –, a group seeking to conserve humpback whales and other cetaceans in the Arabian Sea.  ASWN members include individual scientists from academic institutions and consultancies like the Institute of Marine Science, University of Karachi, Five Oceans Environmental Services, and Megaptera Marine Conservation.


Logo of the Arabian Sea Whale Network


The network also includes representation from national networks such as the Marine Mammal Research and Conservation Network of India,  as well as international NGOs like the World Wildlife Fund (WWF) and Wildlife Conservation Society (WCS), IGOs like the International Whaling Commission (IWC) and the Convention on Migratory Species (CMS) and grass-roots environmental organizations like the Environment Society of Oman and Plan4theland in Iran. Several CSG members have been centrally involved in ASWN from its initiation.

Initiatives involving network ASWN members include:


  • The drafting and approval of a Convention on Migratory Species (CMS) Concerted Action for Arabian Sea Humpback Whales.  This was drafted by ASWN members and strongly supported by a number of ASHW range states at the 2017 CMS Convention of Parties in the Philippines. It recommends a three-year plan of action resulting in the drafting of a regional Conservation Management Plan.  Progress on this is ongoing, and in February 2020 the Concerted Action was extended for another three years.


  • Collaboration with to develop an online regional data platform that will allow standardization and regional analysis of humpback whale distribution and photo-identification data. This work is linked to complementary efforts by Indocet to develop a regional platform for the Western Indian Ocean.


  • Many network members were involved in a March 2019  workshop to identify Important Marine Mammal  Areas (IMMAs) in the Western Indian Ocean and Arabian Seas. In total 37 IMMAs were identified throughout the whole region, of which four are of critical importance for ASHW, as well as other threatened cetacean species. These IMMAs can be explored on the IMMA eAtlas.  The workshop report is available here.


  • A collaborative project is underway between ASWN members in India and Oman to compare humpback whale song that was recorded in  both countries during the same time period. Initial analysis of fairly limited datasets indicate that there is structural similarity in the song in both locations (Cerchio et al. 2018).  Funding and equipment has been secured to expand acoustic studies on both sides of the Arabian Sea.


  • The development of an infographic to raise awareness about the Arabian Sea humpback whale throughout the region.


Infographic portraying key information about the conservation status and threats to Arabian Sea humpback whales.

ASWN members are hoping to foster more regional collaborative acoustic, vessel and genetic studies, capacity building, and inter-governmental collaboration on conservation management, leading to more effective mitigation of the main threats facing Arabian Sea humpback whales.  Efforts continue to try and develop a regional conservation management plan under the auspices of the International Whaling Commission () and the Convention for Migratory Species (CMS).  In the meantime CSG members and the wider network of scientists and conservation organisations involved in ASHW research and conservation will continue with local and regional research and conservation initiatives.


None of this work is possible without funding.  Although a number of Intergovernmental Organisations and regional stakeholders have endorsed the CMS Concerted Action and the ASWN’s progress and priorities, research, fieldwork and conservation planning require expertise, equipment, and most importantly time from a network of individuals who are increasingly trying to achieve ‘more for less’.  This summary proposal for priority ASHW conservation work provides an overview of what could be achieved if more funding and support were available for research, awareness raising and conservation planning in the region.


The CSG posts news items and updates about this population, and these can be found on our News page or at the following links:


September, 2016:  Arabian Sea humpback whales are one of only four populations still considered Endangered under the United States revised Endangered Species Act listing.


April, 2015: Conservation of the Arabian Sea humpback whale



Anderson, R. C., 2014: Cetaceans and tuna fisheries in the Western and Central Indian Ocean. International Pole and Line Federation Technical Report, 2, 133.


Baldwin, R.M., 2003: Whales and dolphin of Arabia. Mazoon Printing Press, Muscat, Sultanate of Oman, 111pp.


Cerchio, S., Willson, A., Muirhead, C., Al Harthi, S., Baldwin, R., Bonato, M., Collins, T., Di Clemente, J., Dulau, V., Estrade, V., et al. (2018). Geographic variation in song indicates both isolation of Arabian Sea humpback whales and presence of Southern Hemisphere whales off Oman. In Document presented to the Scientific Committee of the International Whaling Commission. (Bled, Slovenia: International Whaling Commission), p. 31.


Corkeron, P. J., G. M. T. Collins, K. Findlay, A. Willson, and R. Baldwin. 2011. Spatial models of sparse data to inform cetacean conservation planning: an example from Oman. Endangered Species Research 15(1):39-52.


Dakteh, S.M.H., Ranjbar, S., Moazeni, M., Mohsenian, N., Delshab, H., Moshiri, H., and Van Waerebeek, K. (2017). The Persian Gulf is Part of the Habitual Range of the Arabian Sea Humpback Whale Population. Journal of Marine Biology and Oceanography 6, 1-6.


FAO, 2016: State of the World’s Fisheries and Aquaculture 2016: Contributing  to Food security and nutrition for all. Food and Agriculture Organization of the United Nations, Rome.


IWC, 2016: Report of the Scientific Committee of the International Whaling Commission 2016:  Annex H:  Report of the Sub-Committee on Other Southern Hemisphere Whale Stocks. International Whaling Commission, Bled, Slovenia.


Johnson, A., G. Salvador, J. Kenney, J. Robbins, S. Kraus, S. Landry and P. Clapham, 2005: Fishing gear involved in entanglements of right and humpback whales. Marine Mammal Science, 21, 635-645.


Madhusudhana, S.K., Chakraborty, B., and Latha, G. (2018). Humpback whale singing activity off the Goan coast in the Eastern Arabian Sea. Bioacoustics, 1-16.


Mahanty, M.M., Latha, G., and Thirunavukkarasu, A. (2015). Analysis of humpback whale sounds in shallow waters of the Southeastern Arabian Sea: An indication of breeding habitat. Journal of biosciences 40, 407-417.


Mikhalev, Y. A., 1997: Humpback whales Megaptera novaeangliae in the Arabian Sea. Marine Ecology Progress Series, 149, 13-21.


Minton, G., T. J. Q. Collins, K. P. Findlay, P. J. Ersts, H. C. Rosenbaum, P. Berggren and R. M. Baldwin, 2011: Seasonal distribution, abundance, habitat use and population identity of humpback whales in Oman. Journal of Cetacean Research and Management, Special Issue on Southern Hemisphere Humpback Whales, 185–198.


Minton, G., T. J. Q. Collins, C. Pomilla, K. P. Findlay, H. C. Rosenbaum, R. Baldwin and R. L. Brownell Jr, 2008: Megaptera novaeangliae, Arabian Sea subpopulation. IUCN Red List of Threatened Species,


Minton, G., van Bressem, M.F., Willson, A., Collins, T., Al Harthi, S., Sarrouf Willson, M., Baldwin, R., Leslie, M., Robbins, J., and Van Waerebeek, K. (2020). Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman. In Paper presented to the meeting of the Scientific Committee of the International Whaling Commission. (IWC), p. 25.


Moazzam, M., Nawaz, R., Khan, B., and Ahmed, S. (2020). Whale Distribution in the Northern Arabian Sea along Coast of Pakistan in 2019 based on the information obtained through Fisheries Crew-Based Observer Programme. In Document presented to the meeting of the Scientific Committee of the International Whaling Commission, Volume SC/68B/CMP/08. p. 11.


NOAA, 2016: Endangered and Threatened Species; Identification of 14 Distinct Population Segments of the Humpback Whale (Megaptera novaeangliae) and Revision of Species-wide Listing. In: N. O. a. National Marine Fisheries Service (NMFS) and C. Atmospheric Administration (NOAA) (eds.). Department of Commerce, Washington DC, USA.


Pomilla, C., A. R. Amaral, T. Collins, G. Minton, K. Findlay, M. S. Leslie, L. Ponnampalam, R. Baldwin and H. Rosenbaum, 2014: The World’s Most Isolated and Distinct Whale Population? Humpback Whales of the Arabian Sea. PLoS ONE, 9, e114162.


Sutaria, D. (2019). A Report On Baleen Whale Records And Recent Developments In Marine Mammal Research And Conservation Policy – Update From India. In Document presented to the meeting of the Scientific Committee of the International Whaling Commission. (Nairobi, Kenya), p. 6.


Willson, A., R. Baldwin, S. Cerchio, T. Collins, K. Findlay, H. Gray, B. J. Godley, S. Al Harthi, A. Kennedy, G. Minton, F. Sucunza, A. N. Zerbini & M. J. Witt. 2016. Research update on satellite tagging studies of the Arabian Sea humpback whales in the Sultanate of Oman. In Report presented to the Scientific Committee meeting of the International Whaling Commission, 23. Bled, Slovenia: IWC.


Willson, A., R. Baldwin, T. Collins, B. J. Godley, G. Minton, S. Al Harthi, S. K. Pikesley & M. J. Witt. 2017. Preliminary ensemble ecological niche modelling of Arabian Sea humpback whale vessel sightings and satellite telemetry data. In Document presented to the meeting of the Scientific Committee of the International Whaling Commission, 17. Bled, Slovenia.


Willson, A., M. Leslie, R. Baldwin, S. Cerchio, S. Childerhouse, T. collins, K. Findlay, T. Genov, B. J. Godley, S. Al Harthi, D. W. Macdonald, A. G. Minton, A. Zerbini & M. J. Witt. 2018. Update on satellite telemetry studies and first unoccupied aerial vehicle assisted health assessment studies of Arabian Sea humpback whales off the coast of Oman. In Report presented to the Scientific Committee of the International Whaling Commission, 15. Bled: IWC.


Willson, A., A. G. Minton, T. Collins, S. Al Harthi, M. Sarrouf Willson, S. Cerchio, G. Braulik & R. Baldwin. 2019. Oman Research Update; documenting cetacean diversity and blue whale feeding habitat in Dhofar, southern Oman. In Paper presented to the 2019 meeting of the Scientific Committee of the International Whaling Commission, 14. Nairobi: IWC.