Successful release of an entangled humpback whale in Duqm Port, Oman

The rescue team working to free the whale from gillnets. Duqm Port. Photo courtesy Port of Duqm Company.

On the evening of January 18th, 2021, staff at the Environment Authority – Oman (EA) were notified that  an Endangered Arabian Sea humpback whale had been observed entangled in fishing gear inside the Port of Duqm. This information was shared with the Oman Stranding Network. The whale had apparently been trapped for days, with net and line wrapped inside its mouth and around the flippers, dorsal fin and tail stock. This situation was immediately recognised as a significant risk for both the whale and Port operations.

Recalling the entanglement response training that had been conducted by the International Whaling Commission (IWC) in Oman in 2015, specialists from the Environment Authority, Five Oceans Environmental Services LLC and Future Seas Global SPC, supported by the Environment Society (ESO) and the Port of Duqm quickly mobilised a team and equipment to drive down from Muscat to Duqm, reaching the Port on the following day.  With assistance and personnel from Oman’s Coast Guard, Royal Air Force of Oman (RAFO) and the Port of Duqm, as well as real time advice from members of the IWC entanglement expert panel the team spent the afternoon of the 19th initiating disentanglement.

Click here to watch a video clip of the response.  This shows the team in the day’s last light, attaching buoys to slow the whale down and the prevent it from diving during while the team was working to remove the net. During this intervention, the team noted that as the whale attempted to dive, the upwards force of the buoy helped to unwrap rope and net from the mouth, followed by more rope being dislodged from the flippers and area around the dorsal fin. By the end of the day it was apparent that the only net remaining was on the tail stock.

Video and photographs of the whale during the disentanglement allowed the research team to recognise it as one of the individual whales catalogued in a long-term photoidentification study that has been undertaken in Oman since the year 2000. The whale was identified as individual ‘OM11-016’, which was first photographed near the Port of Duqm in 2010, and then again further south near Hasik in 2011 and 2014.  Most recently this whale had been observed again just outside Duqm Port in October, 2020.

On January 20th, when the rescue team returned to the scene to continue the disentanglement, the whale was no longer in the port. Neither a search of the immediate area using port pilot vessels nor a helicopter search by the Royal Air Force of Oman detected the whale still towing the attached  buoys. However, video shared by a coastguard vessel showed a whale swimming freely in the port later on the day of the 20th. Although the video footage did not allow for definitive identification of the whale, the habitual appearance of this whale in the port over the last 3 months, the absence of any detection during the aerial search, and the observations of the net unwrapping on the previous day all lead the team to conclude that this was very likely the same whale, and that the actions taken on the 19th had enabled the whale to shed the rest of the fishing gear and swim free. In addition, no further sightings of the whale have been recorded since Jan 20th, which, if it were still entangled, might have been expected.

With fewer than 100 individual humpback whales believed to remain off the coast of Oman, the incident highlights a number of issues of critical importance to efforts to protect the species and prevent its extinction:

  • Published research as well as the sighting history of OM11-016 and many other humpback whales in the Oman photo-identification catalogue indicate that whales have a strong affinity to the habitat in the Gulf of Masirah near the Port of Duqm.
  • This highly productive area is also known to be a hotspot for intensive artisanal fishing, with some vessels (referred to locally as dhows) used to set gillnets similar to that found on the entangled whale. These nets are regularly set within the core feeding grounds of humpback whales and are intended to catch large fin-fish that feed on smaller fish like sardines, which are a prey species for the whales. .
  • A recent study presented to the IWC Scientific committee found that 67% of humpback whales photographed off the coast of Oman have scars on their tail stocks consistent with entanglement in fishing gear. Whales can become entangled in both active and abandoned gear. ESO conducted a behaviour change study to address marine wildlife entanglement in fishing nets on Masirah in 2018/2019. The study revealed a low rate of change, highlighting a pressing need to further engage with the fishing community and increase their knowledge of socio-economic and environmental impacts of fisheries. Two awareness-raising videos were created to support the project- a short animated piece and a 5-minute-long feature on the project.
  • Similar gillnets are used throughout the Arabian Sea by registered legal fishing fleets as well as illegal, unregulated and unreported (IUU) fleets. Scientists in the Arabian Sea Whale Network have shared incidents of entanglements occurring off the coasts of Oman, Pakistan, Iran and Somalia. In some of these incidents fishing crews have attempted disentanglements that are extremely dangerous, such as hanging from ropes and entering the water with whales, highlighting the need for more training and guidance throughout the region.
  • Finally, the incident also highlights the persistent threat of ship strikes to Arabian Sea humpback whales and other whale species in the region. Five Oceans Environmental Services LLC spent 3 years working with the Port of Duqm to develop and implement a Whale Management and Mitigation Plan, a programme that could be further strengthened at the Port of Duqm as well as adapted for implementation at other ports in the region. Click here to see one of the key outreach tools used in this plan.

A photo shared on social media of a fisherman from an Iranian vessel operating of the coast of Somalia, attempting an extremely dangerous rescue of a female humpback whale as a calf swims nearby.

New population of blue whales discovered in the western Indian Ocean!

Several ASWN members have been involved in the discovery and description of a new blue whale song, that defines a unique population of blue whales in the Arabian Sea and Western Indian Ocean.  The official press release is copied here below, and a link to the newly published paper in Endangered Species Research can be found here .

Blue whale off the coast of Oman. Copyright Robert Baldwin/Environment Society of Oman.Blue whales are the largest animals that have ever lived on our planet, and they are found around the globe in all oceans. All blue whales sing very low-pitched and recognizable songs, and conveniently for researchers, every population has its own unique song. In a recently published paper in the journal Endangered Species Research, the researchers describe a new blue whale song that is heard from the Arabian Sea coast of Oman across to the Chagos Archipelago in the central Indian Ocean and as far south as Madagascar in the southwest Indian Ocean.

Dr. Salvatore Cerchio, Director of the African Aquatic Conservation Fund’s Cetacean Program and Visiting Scientist at the New England Aquarium, led the analysis of recordings of the whale from three locations in the western Indian Ocean. Dr. Cerchio first recorded the novel song in 2017, during research focused on Omura’s whales in the Mozambique Channel off Madagascar, and he recognized it as a blue whale song that had never been described. Cerchio was also working with a team of scientists collecting acoustic recordings off the coast of Oman in the Arabian Sea. This is part of a research effort focused on the highly endangered Arabian Sea humpback whale, an ongoing collaboration between the Environment Society of Oman, Five Oceans Environmental Services LLC, Oman’s Environment Authority and Oman’s Ministry of Agriculture, Fisheries and Water Resources.

While analyzing the Oman acoustic data, the team recognized the same unusual song. This novel blue whale song was recorded even more prevalently off Oman than Madagascar, and it became clear to the researchers that they had found what was likely a previously unrecognized population of blue whales in the western Indian Ocean.

“It was quite remarkable,” said Cerchio, “to find a whale song in your data that was completely unique, never before reported, and recognize it as a blue whale.” Blue whale song has been extensively studied globally, and several blue whale populations have been identified based on their distinct songs throughout the Indian Ocean.

“With all that work on blue whale songs, to think there was a population out there that no one knew about until 2017, well, it kind of blows your mind,” Cerchio said.

In 2018, the team reported their findings to the Scientific Committee of the International Whaling Commission (IWC), which was in the process of evaluating the status of blue whale populations in the Indian Ocean. The finding created quite a bit of excitement at the meeting, and raised many new questions about blue whale population movements and structure in the Indian Ocean.  Emmanuelle Leroy and Tracey Rogers of the University of New South Wales, in Sydney, Australia, were also conducting acoustic research on blue whales in the Indian Ocean. Upon reading the IWC report on the new song, Leroy recognized that they also had recorded the same song off the Chagos Archipelago in the central Indian Ocean.

“Shortly after we made the first report at IWC,” said Cerchio, “I received an email from Emmanuelle saying, ‘Hey Sal, I think we have that Oman song off the Chagos!’”

The collaborative team grew, and analysis of data from all three sites suggested that the population may spend most of its time in the northwestern Indian Ocean, in the Arabian Sea and to the west of the Chagos. It has long been recognized that a unique population of blue whales resides in the Northern Indian Ocean, but it was assumed that whales in the Arabian Sea belonged to the same population that has been studied off Sri Lanka and ranges into the southcentral Indian Ocean. However, the songs tell a different story.

“Before our recording effort off Oman, there were no acoustic data from the Arabian Sea, and so the identity of that population of blue whales was initially just a guess,” said Andrew Willson from Five Oceans Environmental Services LLC, who led the deployment of the recording units. “Our work shows that there is a lot more to learn about these animals, and this is an urgent requirement in light of the wide range of threats to large whales related to expanding maritime industries in the region.”

Blue whales were hunted to near extinction around the globe during the 20th century, and populations have only started to recover very slowly over the past several decades following the global moratorium on commercial whaling. The Arabian Sea was targeted by illegal Soviet whaling in the 1960’s, an activity that nearly eradicated what were already likely to be small populations of humpback whales, blue whales, sperm whales, and Bryde’s whales.

Some researchers consider both the northern Indian Ocean blue whales and Arabian Sea humpback whales to comprise unique subspecies, not simply populations, making them particularly special and important to biodiversity.

“These populations appear to be unique among baleen whales, in the case of the Arabian Sea humpback whales because of their year-round residency in the region without the same long-range migration of other populations,” Willson points out.

“For 20 years we have focused work on the highly endangered Arabian Sea humpback whale, for which we believe only about 100 animals remain off the coast of Oman,” says Suaad Al Harthi, Executive Director of the Environment Society of Oman. “Now, we are just beginning to learn more about another equally special, and likely equally endangered, population of blue whale.”

Additional coauthors of the paper include Robert Baldwin of Five Oceans Environmental Services LLC, Danielle Cholewiak of NOAA Fisheries, Tim Collins of the Wildlife Conservation Society, Gianna Minton of Megaptera Marine Conservation, Charles Muirhead of Duke University, Tahina Rasoloarijao of the Institut Halieutique et des Sciences Marines, Madagascar, and Maïa Sarrouf Willson of the Environment Society of Oman.

The work was supported by the International Whaling Commission, Renaissance Services S.A.O.G., Shell Development Oman LLC (SDO), and NOAA Fisheries.

New resources related to Important Marine Mammal Areas in the Arabian Sea

The IUCN Marine Mammal Protected Areas Task force has recently updated and upgraded several features on the IMMA e-Atlas.  The e-Atlas includes a number of sites in the Arabian Sea, but now also includes a host of new Important Marine Mammal Areas (IMMAs), candidate IMMAS (cIMMAs), and Areas of Interest (AOIs) in the Extended Southern Ocean and the waters around Australia and New Zealand.  Further more, the map-based interface is now complemented by a user-friendly menu that facilitates filtering by IMMA category or region, as well as targeted searches for specific Areas.



A searchable database also allows more targeted searching by country (EEZ) or species:

The MMPATF site also features a new report that is the result of collaboration between WWF, the IUCN MMPATF, the International Whaling Commission (IWC) and Oceanmind.  The report features an analysis of vessel traffic in 114 IMMAs around the world, including IMMAs identified primarily on the basis of their importance for Arabian Sea humpback whales and other whale species. For every IMMA, a table has been generated with statistics of unique vessels transiting the IMMA each month, as well as heat maps and graphs depicting categories of vessel traffic by month. The report also features a ranking of the sites where the overlap between vessel traffic and whale populations indicates possible risk of ship strikes, and two case studies examining the patterns of vessel traffic in relation to cetaceans in greater detail.   The report highlights two IMMAs in the Arabian Sea as potential hotspots for interactions between ships and whales.

The report can be accessed and downloaded in different formats on this page of the IUCN MMPATF website:

Arabian Sea whales at the 2020 virtual IWC Scientific Committee Meeting

Arabian Sea whales once again featured prominently in discussions of the International Whaling Commission’s Scientific Committee, which was held between May 11th and 24th, 2020.  The meeting was originally scheduled to take place in Cambridge, UK, but for obvious reasons had to shift to a virtual format instead.  In order to accommodate different time zones around the globe, live discussions were limited to two-hour time slots each day, during which parallel Zoom sessions were conducted for different subcommittees.  Many members of the ASWN were able to participate in this virtual format, and some of the key documents and outcomes are highlighted below:

  • As most of you are aware, network members collaborated to produce the annual ASWN Progress report (SC_68b_CMP_11_Rev1). This report summarised ASWN activities over the past year, highlighting progress of individual projects within the network (Oman, the UAE, Iran, Pakistan, India and Sri Lanka), and the extension of the CMS Concerted Action for Arabian Sea humpback whales.  This was complemented by a report submitted by the IWC’s Standing Working Group on Conservation Management Plans (CMP), which included an update on progress toward a joint IWC-CMS CMP for Arabian Sea humpback whales (SC_68B_CMP_17).
  • WWF Pakistan prepared an annual update of the whale sightings reported by the crew-based observers working on the tuna gillnet fleets operating out of Karachi.  This report is available as SC_68B_CMP_08 .
Compiled Megaptera sightings

Map showing all Arabian Sea humpback whale sightings reported by the WWF Pakistan Crew-based observer programme between 2015 and 2019.

  • The team from Oman submitted a report on the visual health assessment of ASHW off the coast of Oman, a project that was funded through the IWC SC in 2018.  This report (SC_68B_CMP_16_rev1) highlighted a relatively high prevalence of tattoo-like skin disease in the population, as well as evidence of ship strikes and entanglement scarring.
  • The Oman team also shared the results of a preliminary study using unoccupied aerial systems (drones) to assess the body condition of ASHW in Oman.  This work was conducted with Fredrick Christiansen of Aarhus university and was presented as SC_68B_CMP_23_rev1.
  • Sal Cerchio and colleagues shared a paper that has been submitted to a peer reviewed journal, providing evidence for a new blue whale song in the Indian Ocean termed the ‘Oman song’.  It was submitted to the meeting as SC_68B_INFO_28.
  • The Flukebook team submitted a paper that includes updates on features being added through collaboration with the Indocet and ASWN teams.  This also includes information about multiple new species for which ‘computer vision’ matching algorithms are now available (SC_68B_PH_06). The Flukebook team also collaborated with Happy-whale to provide a side-by-side comparison of the two photo-ID platforms, which is very helpful (SC_68B_PH_01).
  • A group of researchers working on Sousa plumbea (Indian Ocean humpback dolphins) have collaborated to provide a training dataset of photos that the Flukebook team will now use to develop computer-vision matching algorithms for this species (SC_68B_SM_05).
body condition figure

Aerial photograph (video still frame) of an adult ASHW, showing the location of the body length (purple line) and body width (yellow lines) measurement sites. The picture was extracted from the custom-programmed Graphical User Interface developed by Dawson et al. (2017). Note that this individual also has extensive lesions associated with tattoo-like skin disease.

Although time for discussion was limited, the papers presented raised some interesting questions and a number draft recommendations.  These are taken from the draft report, which is not yet final, and thus wording could be changed:

The Committee reiterates that Arabian Sea humpback whales are a priority candidate for a CMP (IWC, 2019a, p.31) and recommends that the IWC Secretariat and SWG-CMP continue efforts with Oman and India towards development of a CMP in partnership with CMS, which already hosts a Concerted Action for the population. It commends the efforts of scientists within the region and especially the Arabian Sea Whale Network to develop a strong scientific basis to guide the development of a CMP and recommends continuation of research presented at this meeting and the network’s regional collaboration.

Furthermore, the Committee:

(1) welcomes the measures put in place by the Ministry of Environment, Forests and Climate Change, India and the coastal State Governments in India along with local research teams, to promote research, awareness-raising, capacity building and bycatch reduction, and offers technical and scientific support for these efforts where appropriate;
(2) recommends that the work of the crew-based observer programme in Pakistan (SC/68B/CMP/08) continue, if possible mapping fishing effort as well as sightings, and that it be replicated throughout the region where possible, especially in areas where systematic cetacean surveys are not feasible;
(3) encourages continued collaboration between the Pakistan observer programme and the IWC Bycatch Mitigation Initiative (BMI), and also encourages broader collaboration between relevant national governments, researchers and the BMI including through pilot projects on bycatch management, knowledge exchange or requests for capacity building initiatives.
(4) recommends that the use of passive acoustic monitoring to document whale presence and to analyse song be continued in Oman and on the west coast of India and commences off the Sindh and Balochistan coasts of Pakistan, making every effort to ensure simultaneous recordings in all three counties, so that song comparisons can be made across the Arabian Sea;
(5) recommends the continued use of unmanned aerial systems (UAS) and other photographic methods (systematic assessment of images for evidence of disease, epizoites and anthropogenic scarring) to assess body condition and health of ASHW off the coast of Oman with the objective of adopting these metrics as proxy indicators of some of the key ecological attributes related to on-going population trend assessment and conservation planning for ASHWs;
(6) recommends that fishing effort and location of gear that may cause entanglements of ASHW are more accurately mapped throughout ASHW range, especially in the most dense and critical habitat, to assess co-occurrence and risk, in order to better inform mitigation measures;
(7) recommends that a comparative study be conducted between the Oman ASHW catalogue and other Southern Hemisphere Indian Ocean catalogues to assess prevalence and coverage of barnacle scarring and colonization, to determine whether this can be used as a proxy measure for distinguishing ASHW from SH whales.

Three funding proposals were submitted to continue acoustic monitoring for humpback and blue whales off the coasts of Oman and India, and to map human activity as well as carry out more UAS work to assess ASWH body condition off the coast of Oman. These proposals were supported by the Scientific Committee and will be sent to the Commission for endorsement by ‘post’ in the coming weeks.

Due to COVID 19, there will no Commission meeting in the autumn as originally planned. Urgent decisions will be dealt with by ‘postal votes’, and the meeting will take place in September/October 2021 instead. As such, the next IWC Scientific Committee meeting in spring 2021 will be labelled IWC/SC 68C.  We hope that meeting will be able to be held in person in Bled, Slovenia, as planned, and that it will provide an opportunity to assess progress within the network, and make more valuable connections with researchers around the world.

New evidence for movement of Arabian Sea humpback whales between Oman and India

Whale resight

Locations where a highly distinctive humpback whale was photographed in the Gulf Of Masirah, Oman in 2011, and filmed by divers near Netrani Island, Karnataka, India in December 2019.

On December 21st, 2019, scuba divers near Netrani Island off the west coast of India (State of Karnataka) encountered something  extraordinary while travelling to their dive site:  a humpback whale.  The dive masters from Dive Goa, Absolute SCUBA India and West Coast Adventures knew this sighting was special, because they had all been in contact with Dipani Sutaria, who had travelled along India’s west coast from 2016 onward raising awareness of the Endangered status of Arabian Sea humpback whales, and the value of documenting their presence. Seemant Saxena from Absolute SCUBA India and Paritosh Agarwal from Dive Goa entered the water, free-diving through the murky depths to capture a few seconds of underwater footage of the whale to share with Dipani.

Dipani immediately shared this footage with her colleagues working with humpback whales on the other side of the Arabian Sea. She hoped that they would be able to discern some features of the whale in the video that would allow them to identify and match it to one of the individual whales catalogued through 20 years of photo-identification work in Oman. Had it been any other whale, the matching exercise would have been futile, as the water was filled with plankton, and the whale’s features were not very clearly visible. What was visible was a large, white U-shaped scar over the top of the whale’s back, another white scar on the tail fluke where it joined the whale’s trunk, and, as the team peered more closely through the milky water in the video, it seemed that this whale was missing most of the left side of its tail fluke.

Only one whale in the Oman catalogue fit this description – Individual OM11-010, a whale observed and photographed on two consecutive days in October 2011 in the Gulf of Masirah.  Careful comparison of all the available photos of this whale with the whale in the Netrani video revealed more similarities, including more scars and the distinctive notches on the trailing edge of the tail fluke.  The international team of five experienced researchers concluded with certainty that that this must be the same whale.


View of the severely injured dorsal fin photographed in Oman in 2011


Image isolated from video from December 2019

‘This is a hugely exciting finding.’ says Andy Willson from Five Oceans Environmental Services, lead scientist on whale surveys conducted on behalf of the Environment Society of Oman. ‘Firstly it confirms that OM11-010 is still alive, despite the severe injuries we first documented over 8 years ago. Secondly, it provides further evidence that Endangered Arabian Sea humpback whales are moving between Oman and India’.  Trans-Arabian-Sea movement was first documented in November 2017 when a female whale that was satellite tagged off the coast of Oman journeyed to the Southern tip of India and back to Oman again.

However, the sighting is also a sobering reminder of the threats that Arabian Sea humpback whales and other whale and dolphin species face in the Arabian Sea and around the world. Arabian Sea humpback whales are distinct in that they don’t migrate long distances between tropical breeding grounds and polar or temperate feeding grounds.  Instead they remain in the Arabian Sea year-round.  Genetic, acoustic, and photographic evidence shows that the population is isolated from neighbouring populations in the Southern Hemisphere, and that fewer than 100 whales are present off the coast of Oman.

Expert analysis of high resolution images of OM11-010’s injuries indicate that they were caused by entanglement in fishing gear. The phenomenon has been documented in other humpback whale populations as well, and leaves tell-tale signs. The scars on the remaining half of OM11-010’s tail show where a rope or net was tightly wrapped around the fluke in a pattern symmetrical to the line of amputation of the missing fluke.  Scars on the whale’s back and flank show where a rope was so tightly wrapped over the dorsal fin that it cut into the whale’s skin and muscle and left a deep and lasting deformity.  Studies of different humpback whale populations around the world indicate that the proportion of whales bearing signs of fisheries entanglement can range from 25%  in Iceland2, to 65% in the Gulf of Maine2, and as high as 70% off the coast of Alaska3.  These statistics only represent the whales that survive their entanglements.  Bycatch in fishing gear is known to be the biggest threat to marine mammals around the globe, causing an estimated 600,000 deaths annually4.


OM11-010’s damaged tail, photographed in Oman in October 2011. The scars on the remaining half of OM11-010’s tail show where a rope or net was tightly wrapped around the fluke in a pattern symmetrical to the line of amputation of the missing fluke.

Teams on both sides of the Arabian Sea are working hard to protect whales from entanglement and other threats by studying their distribution and behaviour and working with relevant authorities to put protection measures in place.  As part of a long-term study funded by the International Whaling Commission, Sutaria and her colleagues have recently deployed two passive acoustic recorders that will record humpback whale and other marine mammal vocalizations off the west coast of India and provide more insight into when and where whales are present there.  The Indian Ministry of Environment, Forests and Climate Change has listed Arabian Sea Humpback Whales as a priority endangered species for Recovery, has endorsed a Concerted Action under the Convention on Migratory Species, supported the proposal for a Conservation Management Plan under the International Whaling Commission, and has provided funding to the Karnataka State Forest Department for an Arabian Sea Humpback whale research and recovery program.

Willson and colleagues from the Environment Society of Oman and other organisations around the world are adding new and exciting techniques to their 20-year-long study of humpback whales off the coast of Oman, including the use of drones to measure body condition and health.

This recent finding is an excellent example of the need for continued and increased regional collaboration to better understand and protect this Endangered population of whales.

Additional information can be found on the following websites:

Arabian Sea Whale Network website:

IUCN Red List Assessment for Arabian Sea humpback whales:

The Environment Society of Oman’s Website:

Five Oceans Environmental Services:

Marine Mammals of India Website:

For more information contact:


Dipani Sutaria:



2             Basran, C. J. et al. First estimates of entanglement rate of humpback whales Megaptera novaeangliae observed in coastal Icelandic waters. Endangered Species Research 38, 67-77 (2019).

1           Robbins, J., and D. K. Mattila. 2000. Gulf of Maine humpback whale entanglement scar monitoring results 1997-1999, Center for Coastal Studies, Provincetown, MA.

3             Neilson, J. L., Straley, J. M., Gabriele, C. M. & Hills, S. Non‐lethal entanglement of humpback whales (Megaptera novaeangliae) in fishing gear in northern Southeast Alaska. Journal of Biogeography 36, 452-464 (2009).

4             Read, A., Drinker, P. & Northridge, S. P. Bycatch of Marine Mammals in U.S. and Global Fisheries. Conservation Biology 20, 163-169 (2006).


37 Important Marine Mammal Areas identified in the Western Indian Ocean and Arabian Seas

CaptureIn early December 2019, scientists announced the approval of 37 new Important Marine Mammal Areas (IMMAs) in one of the more ecologically rich, yet conservation challenged areas of the worlds oceans—the Western Indian Ocean and Arabian Seas. The new IMMAs highlight key habitats for various threatened marine mammal species, including endangered Indian Ocean humpback dolphins, and the threatened dugong. IMMAs are an important first step toward


An image from the IUCN MMPA Task Force eAtlas showing the new Important Marine Mammal Areas and Areas of Interest in the Western Indian Ocean and Arabiean Seas Region

greater protection efforts, including in some cases, the establishment of marine protected areas.

IMMAs are defined as discrete portions of habitat, important for one or several marine mammal species, that have the potential to be delineated and managed for conservation.  IMMAs are identified through a carefully planned process in which experts are convened in regional workshops to collate and assess all the information about marine mammal habitat in that region. The process draws from published and unpublished sources, often precipitating the most comprehensive review of marine mammal distribution and habitat use in the chosen region.  Each proposed area of interest is assessed based purely on biocentric criteria , that fall into four main categories: (1) Species or Population Vulnerability, (2) Distribution and Abundance (small resident population, Large aggregation),  (3) Life Cycle Activities (Breeding habitat, Feeding habitat, migration routes) (4) Special Attributes (distinctiveness, diversity). 

Once submitted, each IMMA proposal undergoes a critical scientific review by at least two independent reviewers, much like the submission process of peer-reviewed scientific journals.  Only proposed areas that can fully demonstrate fulfillment of at least one criteria attain full IMMA status, after which point they are published on the  eAtlas, and can be used in conservation planning by a variety of stakeholders.  It is hoped, for example, that industry can use this information to either avoid IMMAs or effectively  mitigate the impact of any of their planned activities in them, and that governments can use IMMAs to help guide their deliberations on where to place marine protected areas or other coastal zone management efforts.

 The IMMA process for the Western Indian Ocean and Arabian Seas was launched in 2019.  A regional workshop took place on March 4th-8th 2019, in Salalah, Oman, and involved 38 marine mammal scientists and observers from 15 countries, with several more scientists contributing to assessments and proposals remotely. The IMMAs identified as a result of these workshops and subsequent independent review can now be viewed on an IMMA eAtlas.  Efforts to use these IMMAs to guide effective conservation measures are already underway, with the example of a recent implementation visit to Bazaruto Archipelago to Inhambane Bay Important Marine Mammal Area (IMMA), Mozambique in November 2019.

The 37 IMMAs in the Western Indian Ocean and Arabian Seas were identified for the Arabian Sea humpback whales, Indian Ocean humpback dolphins, high cetacean species diversity, dugong aggregations, concentrations of Omura’s whale, as well as three different populations of blue whales.

Follow the links below to find more information on each of the 37 new IMMAs:

  1. Aldabra Atoll IMMA
  2. Bazaruto Archipelago and Inhambane Bay IMMA
  3. Cape Coastal Waters IMMA
  4. Comoros Island Chain and Adjacent Reef Banks IMMA
  5. Dhofar IMMA
  6. Farasan Archipelago IMMA
  7. Greater Pemba Channel IMMA
  8. Gulf of Kutch IMMA
  9. Gulf of Masirah and Offshore Waters IMMA
  10. Gulf of Salwa IMMA
  11. Indus Estuary and Creeks IMMA
  12. Kisite-Shimoni IMMA
  13. Lakshadweep Archipelago IMMA
  14. Lamu Offshore IMMA
  15. Madagascar Central East Coast IMMA
  16. Maldives Archipelago and Adjacent Oceanic Waters IMMA
  17. Mascarene Islands and Associated Oceanic Features IMMA
  18. Menai Bay IMMA
  19. Miani Hor IMMA
  20. Mozambique Coastal Breeding Grounds IMMA
  21. Muscat Coastal and Shelf Waters IMMA
  22. Nakhiloo Coastal Waters IMMA
  23. North East Arabian Sea IMMA
  24. Northern Gulf and Confluence of the Tigris, Euphrates and Kuran IMMA
  25. Northern Red Sea Islands IMMA
  26. North West Madagascar and North East Mozambique Channel IMMA
  27. Oman Arabian Sea IMMA
  28. Seychelles Plateau and Adjacent Oceanic Waters IMMA
  29. Shelf Waters of Southern Madagascar IMMA
  30. Sindhudurg-Karwar IMMA
  31. South East African Coastal Migration Corridor IMMA
  32.  South West Madagascar and Mozambique Channel IMMA
  33. Southern Coastal Shelf Waters of South Africa IMMA
  34. Southern Egyptian Red Sea Bays, Offshore Reefs and Islands IMMA
  35. Southern Gulf and Coastal Waters IMMA
  36. Toliara, St. Augustine Canyon and Anakao IMMA
  37. Watamu-Malindi and Watamu Banks IMMA

Marine Mammal Podcast features ASWN member, Umair Shahid


Spinner dolphins bycaught in tuna gillnet fisheries off the coast of Pakistan.  Photo courtesy of WWF Pakistan

Listen to ASWN member Umair Shahid talk about cetacean bycatch in the Indian Ocean on the Marine Mammal Science Podcast by clicking here.  The talk features a great description of WWF Pakistan’s innovative crew-based observer programme that has yielded valuable information on bycatch rates and species, as well as successful bycatch reduction methods.  Umair also talks about his work with the Indian Ocean Tuna Commission and the International Whaling Commission’s Bycatch Mitigation Initiative, as well as regional efforts to reduce bycatch of many different taxa.

Two new Reports on cetaceans in the Indian Ocean and Arabian Seas!


Participants to the IWC Workshop on Bycatch Mitigation Opportunities in the Western Indian Ocean and Arabian Sea.  May 7-9, 2019, Nairobi.

This week two new workshop reports have been released, each containing a wealth of valuable information related to conservation of cetaceans in the Western Indian Ocean and Arabian Seas.  The first is the Report of the IWC Workshop on Bycatch Mitigation Opportunities in the Western Indian Ocean and Arabian Sea. It is available for download by following this link  or directly through the IWC archive

This workshop, which was held in Nairobi in conjunction with the IWC Scientific Committee meeting was funded by generous contributions from the Government of France, the US Marine Mammal Commission, the Pew Foundation, the Western Indian Ocean Marine Science Association.  It included a range of presentations on innovative approaches to assessing, monitoring and mitigating bycatch, as well as some hands-on sessions where participants worked together to identify potential bycatch hotspots, where further research and mitigation efforts can be directed.  The workshop resulted in a number of recommendations for collaborative work to reduce bycatch in the region.  A few key recommendations are pasted in the table below.

Screen Shot 2019-03-09 at 15.00.06

The second Report of note is the Preliminary report of the Workshop on identification of Important Marine Mammal Areas (IMMAs) in the Western Indian Ocean and Arabian Seas. This report can be downloaded here:

Candidate IMMA proposals drafted during that workshop are in the final stages of review and revision.  Once the final IMMAs and Areas of Interest have passed the independent reviewers and correspondence concluded with those needing further information, the IMMAs and AoI will be placed on the IMMA e-Atlas with background PDFs for each IMMA. Once that is in place, a final report will be issued with the final numbers and list of IMMAs and AoI for the region.

Both workshops involved a number of ASWN members, and allowed them to share their knowledge and expertise, while also learning from ‘neighbours’ working in other parts of the Indian Ocean.  Both workshops also paved the way forward to continued and increased collaboration to address the challenges of protecting cetaceans and their habitat.


ASWN members Dipani Sutaria and Mohammed Moazzam Khan work with IMMA Chair, Erich Hoyt on proposals for Important Marine Mammal Areas in India and Pakistan.


Summary of Recommendations of the IWC Bycatch Workshop:

  • The workshop recommends that governments in the Indian Ocean region establish or strengthen bycatch assessment and reduction programmes as a matter of urgency, with priority on bycatch hotspots areas identified across the region. Associated actions could include rapid risk assessments, on-board data collection, mitigation trials (experimental and existing measures) and/or implementation of effective management measures.
  • The workshop recommends that governments and other relevant stakeholders in the Indian Ocean region carry out cetacean sampling surveys to collect information on species abundance and distribution at national and regional scales and encouraged that this information could be shared with the IWC Scientific Committee.
  • The workshop recommends that the IWC (including through its Conservation Committee) develop and communicate recommendations to governments on the importance of addressing bycatch through policies and other measures that support bycatch mitigation efforts, and of more coherent approaches across government departments with different mandates; and promotes the sharing of information and experience between its contracting members.
  • The workshop recommends that the BMI assist bycatch reduction efforts in the Indian Ocean region, including through:
    •  raising awareness and prioritisation of addressing cetacean bycatch in small to medium-scale gillnet fisheries through its engagement with member countries and other IGOs and NGOs;
    • developing a regional road map for bycatch reduction (including assessment, monitoring and mitigation) in collaboration with other relevant bodies (e.g. FAO, IOTC, CMS, national governments);
    • providing technical assistance to countries to assess different aspects of cetacean bycatch (e.g. monitoring, assessment, mitigation) and support and promote multidisciplinary monitoring (e.g. social science techniques, economics) and mitigation approaches, including though capacity building;
    • exploring means of more consistent and sustainable approaches for funding of bycatch mitigation efforts.
  • The workshop recommends that bycatch reduction efforts employ a multi-disciplinary and multi-taxa approach at local, national and international scales.
    National Governments in the Indian Ocean region; scientific research community;
  • The workshop recommends that the BMI provides technical assistance to governments and other relevant stakeholders within the Indian Ocean region in the design of experimental mitigation trials that are both scientifically rigorous and which supports the livelihoods of fishing communities, as far as is possible.
  • The workshop recommends that the IWC (through the BMI and through its conservation and scientific committees) assist efforts to communicate scientific and conservation advice to decision makers in collaboration with other inter-governmental organisations and non-governmental organisations.
  • The workshop recommends to governments and other relevant stakeholders in the Indian Ocean region that bycatch monitoring and reduction efforts use (where appropriate) crew-based approaches for collecting data on bycatch and mitigation measures (including where observer programmes are not feasible due to the size of vessel, the large numbers of small and medium-scale fishing vessels, trip length, safety concerns etc).
  • The workshop recommends that the BMI assist national efforts by developing a toolbox of more effective tools for communication with fishing communities and associations including the promotion of fisher-exchanges to share experiences of bycatch mitigation efforts and efficacy.
  • The workshop recommends renewed efforts by the research community and fisheries technologists in the research and development of low-cost bycatch mitigation and monitoring solutions, particularly for gillnet fisheries and the scaling-up of testing of existing measures (e.g. lights and acoustic deterrents, and experimental low-tech tools) in different fisheries and locations.
  • The workshop recognised the importance of capturing socio-economic information as part of a holistic and multi-disciplinary approach, and therefore recommends to countries that monitoring and mitigation programmes should also integrate collection of economic data (CPUE, catch value etc) to be collected and analysed alongside bycatch information.
  • The workshop recommends that governments in the Indian Ocean region consider pro-active reassurance to fishers that there will not be negative consequences in response to reporting bycatch and furthermore recommends to use fisher reported data for monitoring and bycatch management purposes rather than for compliance and enforcement.
  • The workshop recognised the growing importance of REM methods and the possibility for cost-effective monitoring at a fleet-scale, and therefore recommends that governments and relevant stakeholders in the Indian Ocean region engage in trialling REM approaches for bycatch monitoring, including low-cost methods for small and medium-scale vessels (and in other vessels as appropriate).
  • The workshop recommends that the BMI provide technical assistance upon request on the REM systems available and their applicability to a specific situation.
  • The workshop concluded that there was an important need to raise the profile of cetacean bycatch and promote bycatch reduction efforts within the context of RFMOs, and specifically within the Indian Ocean and it therefore recommends that:
    • The BMI engage more formally and more regularly with the IOTC, the South West Indian Ocean Fisheries Commission (SWIFOC) and other relevant RFMOs, including in collaboration with other relevant organisations, to encourage more discussion and action of cetacean bycatch monitoring and mitigation in the fisheries under their management. This could be achieved through direct observer status and/or the appointment of regional representatives/contacts to maintain an overview of relevant RFMO meetings and opportunities to participate and/or present information.
    • IWC Contracting Governments undertake further efforts to improve the quality and quantity and reliability of cetacean bycatch data reported to the IOTC and to other bodies (including the IWC national reports) and for small-scale fisheries.
    • Bycatch Mitigation Initiative; IWC Conservation Committee; IWC Secretariat; National governments in the Indian Ocean region
    • That the BMI support where appropriate contracting and non-contracting governments in the exchange of cetacean bycatch information and experiences between neighbouring countries and support the development of transboundary approaches including through BMI engagement with RFMOs
    • That the BMI explore its potential to assist countries in fulfilling their reporting requirements under IOTC, as well as the potential for greater sharing of information on bycatch between the IWC and FAO/the RFMOs.

Blue Whales in Oman; the Sultanate’s most diverse marine mammal hotspot just got hotter!

The following is a blog shared by ASWN member Andy Willson that provides some insight and inspiration for cetacean conservation efforts off the coast of Oman, based on recent surveys conducted in the Dhofar region.  The results of these surveys were also presented to the International Whaling Commission’s recent Scientific Committee meeting in May, and the more scientific version can be found here.  But for a more informal and entertaining read, pour yourself a cup of tea, and sit down and Enjoy the following!

Blue whale medley April 2019

A blue whale photo medley courtesy of Five Oceans Environmental Services, Oman.

The Five Oceans Environmental Services (5OES) team based in Muscat, Oman spent early April 2019 conducting a cetacean survey off southern Oman. Following on a hot trail of discovery, the recent survey documented blue whales conspicuously feeding in this area for the first time. Maturing in step with the receding hair-lines of its once young explorers, scientific evidence from this study site is beginning to prove that it is one of the most diverse, exciting and confusing areas for cetacean research in the Northern Indian Ocean (NIO).

Formalised cetacean research in Oman took off in the late nineties/early 2000s in response to growing global interest in records of humpback whales off Oman’s coast. Hundreds of kilometres of coastline lay waiting to be explored by a ‘green’ team of early career researchers armed with a shaky old 4WD, a retired fishing boat, a point and shoot 35mm camera and a stash of donated baked beans and pitta bread. Initial records pooled from merchant navy records, incidental sightings and soviet whaling records from the mid-60s provided evidence that the humpbacks found off the coast could be part of a unique and isolated population. With an astonishing talent for establishing scientific collaboration and busking for support, the team’s efforts were rewarded in 2008 with formal recognition that Oman’s humpbacks were indeed an isolated population of humpbacks, and so graduated from their previous designation by the International Whaling Commission (IWC) of ‘Population X’ into a more formal title, ‘Arabian Sea humpback whales’. Years of genetic study, involving biopsying whales to collect tissue samples for subsequent DNA analysis in the lab had proved that the whales were totally different from all other humpbacks in the world and had been isolated for an estimated 70,000 years. At the same time, photo-ID mark-recapture population assessment provided estimates of fewer than 100 animals residing off Oman. This prompted an urgent requirement to answer more questions relating to conservation management. More complex ecological investigations began to emerge in the form of species distribution modelling, round the clock acoustic monitoring and, ultimately, satellite tracking. These new methods required refocusing the team’s very limited survey resources into just two favoured study sites.

Early on, one of these favoured study sites on the corner of the Hallaniyats Bay in southern Oman began to yield results beyond expectations. Almost every survey the area resulted in encounters with new species or observations of new behaviour. At the last count the team which includes the Environment Society of Oman and Ministry of Environment and Climate Affairs had documented 18 of the 21 species known to Oman. At first look the guest list looks like a collection of misfits – representing some of the most deep diving and wide ranging of offshore species alongside those that hug the coast so tightly they could easily benefit from legs:  Indo-Pacific common dolphins (Delphinus delphis tropicalis), common bottlenose dolphins (Tursiops truncatus), spinner dolphins (Stenella longirostris), Indo-Pacific bottlenose dolphins ( Tursiops aduncus), rough-toothed dolphins (Steno bredanensis), Indian Ocean humpback dolphins (Sousa plumbea), Risso’s dolphins (Grampus griseus), false killer whales ( Pseudorca crassidens), killer whales ( Orcinus orca), dwarf sperm whales (Kogia sima), melon-headed whales (Peponocephala electra), short-finned pilot whales (Globicephala macrorynchus), Cuvier’s beaked whales (Ziphius cavirostris), sperm whales(Physeter macrocephalus), Bryde’s whales (Balaenoptera edeni), Arabian Sea humpback whales (Megaptera novaeangliae)and blue whales ( Balaenoptera musculus cf indica).

Evidence from 17 years of work at this site has recently been compiled to nominate the study site as a candidate for one of the world’s most ‘Important Marine Mammal Areas’ (IMMA). This was proposed at a workshop organised by the IUCN Marine Mammal  Protected Area Task Force in March 2019 in Salalah, Oman.  Self-promoting, the site ticks almost every criterion in the book for what is required to define an important area for whales and dolphins, from the high diversity of species to its quirky isolated and endangered residents. One of these residents, ‘Quasimodo’ a particularly hump-backed female Arabian Sea humpback whale with a spinal abnormality made a sneak appearance as a few members of the task force team passed through the site in mid-March on their way out of the IMMA workshop.


Quasimodo, a particularly ‘humped’ humpback whale, photographed in Dhofar in 2011.  Courtesy of the Environment Society of Oman.

The high diversity of cetaceans with both coastal and offshore habitat preferences is thought to be related to the unique bathymetric and oceanographic conditions. The coastline on one side of Hasik is characterised by a mountain escarpment which plummets down to the continental slope offshore, whilst to the other side is a large shallow embayment of continental shelf. The interface between these seafloor features generates strong, sustained currents that promote year round pulsing of upwelling nutrient-rich waters from the deep ocean. With the onset of the southwest Indian Monsoon during the summer months, the upwelling along the southern coast of Oman is amplified, transforming the space from a sub-tropical to a temperate oceanic regime. Only accessible to the research team outside of this turbulent season the humpback whales have been observed consistently in the area every winter and spring. Singing (related to breeding) is the popular pastime of a group of approximately six male humpbacks that are consistently re-encountered at the site year on year. More unconventional activities have also been observed, such as switching between competitive breeding related behaviour and ‘bubble-net’ feeding just breaths apart. Such habitat use is considered a unique trait of this non-migratory population where social and dining engagements can all be serviced in the same time and space. Humpback whale populations in all other parts of the world typically have such delights separated by months of travel and thousands of kilometres as they migrate between polar feeding areas and tropical breeding grounds.

Dhofar map with sightings

The coastline on one side of the Hallaniyats Bay is characterised by a mountain escarpment which plummets down to the continental slope offshore, whilst to the other side is a large shallow embayment of continental shelf. This figure shows that unique bathymetry and the species encountered in the Hallaniyats Bay region, southern Oman between March 2018 and April 2019 (courtesy of Five Oceans Environmental Services).

The presence of a smaller lesser known baleen whale, the Bryde’s whale, has also been documented on almost every survey in the area. This species seems to specialise in taunting the research team. During the last survey, Bryde’s whales pulled off their best trick by breaching in front of the teams’ campsite on a number of occasions and then running off to hide (although we eventually managed to catch up with them). As much as a mystery as the blue whales, this tropical whale is notoriously difficult to study due to its stealthy speed and preference for surfacing just where the research boat isn’t. As such it lies high on the list of miscreants for the research team to investigate.

Blue whales are infrequently observed in Oman and were documented off the survey site for the first time in 2011. Their presence elsewhere in the northern Indian Ocean (e.g. off Sri Lanka) is better known, although the taxonomy and population structure remains unresolved. Echoing the Arabian Sea humpback whale enigma, the jury is out on the details of their population affinity and range. Are they unique and isolated to the NIO or are they part of a larger more wide-ranging population in the Indian Ocean? Recent literature cites blue whales found in the NIO as either a subspecies of a smaller form of blue whale known as pygmy blue whales found across Indian and Pacific Oceans (Balaenoptera musculus brevicauda – Ichihara, 1966), or, intriguingly as another unique whale, the Indian Ocean blue whale (Balaenoptera musculus indica – Blythe, 1859). The ‘indica’ sub-species designation identifies the taxonomy of this smaller form of blue whale with a more restricted geographical range, not dissimilar to the Arabian Sea humpback. Efforts to resolve this impasse on population affinity and range have so far been painstaking. To approve the ‘indica’ form the evidence needs to demonstrate geographical isolation and significant biological differences. This is where the story slides from blue to grey.

To date only two genetic samples have been processed from blue whales in the NIO and the results demonstrated no discernible difference in the DNA sequence between pygmy blues found in the southern Indian Ocean and their counter-parts to the north. However, the sample size was considered too small to draw reliable conclusions. Study of historical whaling data shows that blue whales encountered in the NIO are 0.5m shorter than southern blues; a relatively small difference. However, the cookie cutter shark bites observed by whalers on blue whales taken in the southern Indian Ocean have not been observed on blues to the north of the equator. Whalers have also described a gap in the central Indian Ocean where very few blue whales were ever observed, suggesting there may be no movement north and south across the equator. With song often used as a descriptor for placing geographical limits on the population structure the ‘isolationist’ theory is further supported by the unique song or call types recorded off Sri Lanka and the Chagos Archipelago but never further south in the Indian Ocean. Meanwhile, sightings and strandings data show blue whales to be present in the Indian Ocean year-round. Recent re-evaluation of whaling records has revealed no discernible seasonality to  the reproduction of blue whales in the NIO, where-as the breeding season of blues in the SIO is understood to occur only in the austral winter.

Last year a new twist emerged with the Oman team reporting to the IWC Scientific Committee a completely new baleen whale song type. The song was recorded in 2012 at the Hasik study site with call attributes that imply the source of the ‘baritone’ vocalisation was most likely from a blue whale.

With that as background, it’s no wonder that we were reeling with expectation as we bounced our way towards a sighting called-in by the shore-based team on day three of our survey in April. This was the latest in the season we had been on survey at the site for many years. Multiple tall blows could be seen from the boat through the building Force 5 seas with momentary glimpses of a broad back that slowly transformed into the unmistakable mottled steel grey blue of a blue whale, rolling into a dive. Thinking we were in for a brief sunset encounter with a transiting ‘5 O’clock whale’ the team moved into position to collect photo-ID data before being left trailing in a pool of bright orange faeces as the whale dove out of site with its tail high in the air. The fluking behaviour is not considered a common behaviour of blue whales, but is well documented off the coast of Sri Lanka on feeding aggregation sites. However, the bright orange faeces was certainly a sign of recent feeding and the team bagged a sample followed by a well-timed biopsy on the next surfacing of the animal. Over the following 2 days we documented at least another four animals performing regular dives with a couple of minutes surface time followed by 10-14 minute dive time intervals. The whales ranged in length between 12m and at least 18m. In total five biopsies and two separate faeces samples were gathered, together with a collection of 100’s of photos for ID use. The biopsy samples are the first to have been taken from live blue whales in Oman: the two previous DNA samples came from stranded whales. The results are accompanied by referenced photo-ID images of the biopsy takes.

Blue whale dive sequence

As before this special corner of the Indian Ocean has produced the unexpected. The game is now on to get the biopsy and faeces samples sequenced and photos processed to ready them for comparison with other catalogues in the Indian Ocean. 2019 could be the year we get closer to unravelling the mystery of blue whales in this part of the northern Indian Ocean. Or will these investigations just throw up yet more questions? Which-ever way this pans out the team is aware there is far more work to be done to help understand, and ultimately safeguard, this important corner of our blue planet.



Collaboration for Killer Whales in the Northern Indian Ocean

Still images extracted from video taken by fishermen on May 14 2017, near to Hendorabi Island, Hormozgan Province, Iran.

Two recent publications have  highlighted the value of regional collaboration and broad-scale (social) networking for cetacean research and conservation in the Northern Indian Ocean and Arabian Seas.

The first is a newspaper story that tells the fascinating tale of a sighting of killer whales made by an Emirati businessman on his way home from a fishing competition. A video of the sighting posted on social media drew the attention of local researcher and ASWN member, Ada Natoli, founder and director of the UAE Dolphin Project. She has been using social media to support a cetacean sightings and strandings network in the UAE.  The video footage was shared with with Georgina Gemmell, a scientist who coordinates the Northern Indian Ocean Killer Whale Alliance (NIOKWA), and other scientists in the region. Collectively they were able to determine that these whales were members of a group called ‘Pod 11’ who were first observed off Abu Dhabi in 2008, and then seven years later in Sri Lanka. You can read more about this sighting in the original newspaper article here.

The second publication is a journal article published today in ‘Zoology in the Middle East‘.  This short communication documents three killer whale sightings made in Iranian waters in 2017 and 2018. These were also sightings reported by non-scientists, recorded with video using smart phones, and then shared with cetacean researchers.  ASWN members from Iran’s Plan for the Land Society were able to collaborate with other scientists in the region, as well as the NIOKWA to analyse the video footage and identify at least one individual whale – a female or young male- who was recognisable and present in two of the 3 sightings.  Although no matches were made between this identified whale and other individuals in the NIOKWA catalogue, these three sightings from a region where so little is known about killer whale distribution and movements offer valuable insights where no previous data existed, as well as motivation to learn more about this intriguing species.