Arabian Sea Humpback Whales

Revised November 2019

Background and threats

 

Historical whaling records and 20 years of research conducted off the coast of Oman have revealed that Arabian Sea humpback whales are the only non-migratory population of humpback whales in the world. This unique, small population 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 1960’s 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, IWC, 2016).  However, very little is known about Arabian Sea humpback whales in other parts of the Arabian Sea.

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

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 60,000 cetaceans per year may die in fisheries in the Central, Western and Northern Indian Ocean (Anderson, 2014). 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 (Minton et al., 2011) and at least 10 individuals have been disentangled by rescue teams and fishermen in Omani coastal waters over the last 20 years (Baldwin 2003).

 

  • 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, has nevertheless resulted in a significantly improved understanding of the situation. However, there remains a lack of conservation action and, in the absence of efforts to mitigate the threats, the Arabian Sea humpback whale population is considered at high risk of extinction. This risk is recognized by the IUCN (Minton et al., 2008), the IWC (IWC, 2016), and the United States Endangered Species Act, which designates the Arabian Sea population as one of only four humpback whale populations in the world still considered to be Endangered (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 – arabianseawhalenetwork.org), a group seeking to conserve humpback whales and other cetaceans in the Arabian Sea.  ASWN members include academic and independent scientists as well as representatives of large international NGO’s like World Wildlife Fund (WWF) and Wildlife Conservation Society (WCS), IGO’s like the International Whaling Commission (IWC) 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.

 

 

Logo of the Arabian Sea Whale Network

Initiatives involving network 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.

 

  • 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 IMMA workshop held in Salalah, Oman. The workshop was convened in order to identify candidate important marine mammal areas; A total of 55 candidate Important Marine Mammal Areas for the Western Indian Ocean and Arabian Seas, (cIMMAs) were identified which is the largest number proposed from a single workshop to date. Thirteen Areas of Interest (AoI) were identified as areas where further research is merited prior to their nomination as cIMMAs. Six of these cIMMAs  were identified as being of critical importance for the ASHW, as well as other threatened cetacean species. The cIMMA proposals are undergoing peer review, and those that are approved will be added to the IMMA eAtlas.  The workshop report is available here.

 

 

 

  • Members in India are now using acoustic methods to further establish where areas of importance might occur. These are focusing on hotspots identified using secondary data sources, including incidental sightings.

 

  • 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. While the challenges facing those working with this population are daunting, the support and involvement of a global network of whale scientists and conservation experts associated with IUCN, the International Whaling Commission (IWC) and the Convention for Migratory Species (CMS) is considered extremely valuable and encouraging.

The above provides a background to the Arabian Sea humpback whale population and its conservation.

 

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

 

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

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

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

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

 

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.

 

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.

 

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.

 

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.

 

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.

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