Arabian Sea Humpback Whales

Updated January 2024

Background and threats

Historical whaling records and over 20 years of research conducted off the coast of Oman have revealed that the Arabian Sea humpback whale subpopulation does not undertake seasonal migrations between high-latitude feeding grounds and low-latitude areas for mating, calving and nursing as do all other known humpback populations. This small endangered population (Minton et al., 2008) is genetically differentiated (Pomilla et al., 2014) and may represent a new subspecies that diverged from other Indian Ocean humpback whale 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 indicated that fewer than 100 individuals remained in the coastal waters of Oman in between 2000 and 2004 (Minton et al., 2011). Photo identification, satellite tracking, and acoustic monitoring in the two main study areas in Oman have revealed a high degree of site fidelity and the regular occurrence of behaviour associated with both feeding and reproduction (Minton et al., 2011, Corkeron et al. 2011, Willson et al., 2017, ESO, 2022).

Less is known about Arabian Sea humpback whales (ASHW) in other parts of the Arabian Sea, but emerging evidence collected through opportunistic observations, interviews with fishermen, acoustic recordings, and reports from fishing crews show that individuals continue to visit areas where whales were taken in the 1960s

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

off the coasts of Pakistan and India (e.g., Mahanty et al., 2015; Madhusudhana et al., 2018; Sutaria, 2019; Moazzam et al., 2020) as well as the Arabian Gulf (Dakteh et al. 2017).  There is also recent evidence from satellite tracking 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, among 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, now account for over 40% of all tuna landings in the region, and although observer coverage of fisheries in the Arabian Sea is extremely limited, cetacean bycatch is unquestionably prevalent. A recent study suggests that as many as 4.1 million small cetaceans have died in tuna gillnet fisheries in the Indian Ocean between 1950 and 2018 (Anderson et al., 2020). Credible estimates of the number of humpback whales entangled each year don’t exist, but 30—40% of the individual whales 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., 2022).

• 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: This can carry threats of disturbance from seismic surveys and from construction and drilling noise, associated vessel traffic, and 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.

A collaborative rescue team comprised of government and non-government stakeholders trained by the International Whaling Commission in 2015 working to free a humpback whale from gillnets in Duqm Port, Oman in January 2021. Photo courtesy Port of Duqm Company.

Throughout the region, stakeholder awareness of the conservation status of Arabian Sea humpback whales and the many threats they face is low. However, awareness-raising efforts in Oman, and more recently in other countries of the region, have significantly improved awareness and 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 cetaceans. However, without further tangible measures to mitigate the threats, the Arabian Sea humpback whale population is considered at a high risk of extirpation. The sub-population is designated as Endangered on the IUCN Red List of Threatened Species (Minton et al., 2008). The International Whaling Commission has repeatedly expressed concerns (e.g., IWC, 2016), and this is one of only four humpback whale populations in the world still listed as Endangered under the United States Endangered Species Act (NOAA, 2016).

Regional Collaboration for Conservation and Research

A workshop held in January 2015 addressed the pressing conservation concerns and led to the formation of the Arabian Sea Whale Network (ASWN – arabianseawhalenetwork.org), a group seeking to conserve humpback whales and other cetaceans in the Arabian Sea.  ASWN members include many CSG members, individual scientists and conservation managers from academic institutions, IGOs, international and national NGOs and independent consultancies (see https://arabianseawhalenetwork.org/about-2/aswn-participation-and-support/ for more details). The ASWN has a part-time coordinator and a part-time Communications focal point. Communication is supported through a Google Group mailing list and a website:  https://arabianseawhalenetwork.org/

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 ASWN members include:

• The drafting and approval of a Convention on Migratory Species (CMS) Concerted Action for Arabian Sea Humpback Whales. The Concerted Action 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, including the production of a regional Conservation Management Plan. Progress on this is ongoing, and in February 2020 the Concerted Action was extended for another three years. In 2023 a progress report was submitted with the recommendation to extend the Concerted Action for another three years in order to complete the final objective of drafting and beginning to implement a joint regional Conservation Management Plan in collaboration with the International Whaling Commission.

• Collaboration with Flukebook.org 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.

• Production 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 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 continue to pursue local and regional research and conservation initiatives, and a CMS Concerted Action for the species helps to provide a framework for this action.

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

August 22^nd, 2019: Cetaceans in the Western Indian Ocean

February 3^rd, 2018: Arabian sea humpback whale crosses from Oman to India!

March 3^rd, 2017: New infographic from the Arabian Sea Whale Network

April 20^th, 2015: Conservation of the Arabian Sea humpback whale

References

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.

Environment Society of Oman (ESO) and Environment Authority of Oman. 2022. Complementing Development with Conservation: A Workshop for the Management Planning for Arabian Sea Humpback Whales in Oman, Edited by G. Minton. Available from https://arabianseawhalenetwork.org/wp-content/uploads/2022/11/Oman-ASHW-Conservation-Management-Workshop-Final-Report_2023.02.22.pdf

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, http://www.iucnredlist.org/details/132835.

Minton, G., Van Bressem, M.F., Willson, A., Collins, T., Al Harthi, S., Sarrouf Willson, M., Baldwin, R., Leslie, M., Van Waerebeek, K., 2022. Visual Health Assessment and evaluation of Anthropogenic threats to Arabian Sea Humpback Whales in Oman. Journal of Cetacean Research and Management 23, 59-79.

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.