[Research & Fieldwork]

February - March Survey 2003

The Oman Whale and Dolphin Research Group (OWDRG) recently returned from their fourth annual survey of the Dhofar region, where they focused on recording the distribution and behaviour of humpback whales and a number of other species of cetaceans. Although fewer humpback whales were observed than hoped or expected, some exciting and significant discoveries were made.

The survey was scheduled to begin in the middle of February in the Gulf of Masirah. However, severe weather conditions and rough seas hindered this portion of the survey, and the group was only able to begin work in the Salalah region on February 23^rd. From this date through the 15^th of March, the team carried out a combination of nearshore surveys for coastal dolphins, and wider ranging surveys for whales and offshore dolphins (see map below).

Nearshore surveys focused on humpback and bottlenose dolphins, and both species were encountered regularly throughout the region between Mughsayl and Shuwaymiyah. Photographs taken of individual dolphins over the past three years can be used to recognise individuals and to augment future studies of the movements and habitat use of these species in the region. On many occasions skin samples were also collected from these species. Genetic analysis of samples collected on previous surveys revealed that the Dhofar region may be home to a very distinct population of humpback dolphins. These dolphins may be more closely related to populations studied on the east coast of Africa than to other populations in Oman. The additional twelve samples collected on this survey will help to shed light on this unexpected relationship.

Humpback whales, the other target species of the survey, were frustratingly few and far between. This species is of particular interest as the Arabian Sea is believed to be home to the only non-migratory population of humpback whales in the world. Understanding their seasonal distribution, feeding and breeding behaviour and ecology is vital for future conservation efforts. In total 16 whales were observed on the survey, and many of them proved very difficult to approach and photograph. However, some extremely valuable data were collected.

Skin samples were collected from three whales and the analysis of these should reveal the gender of sampled whales and further clarify the relationship between Omani whales and other neighbouring populations. Analysis of samples collected on previous surveys revealed that although some genetic characteristics are shared with populations from Madagascar, South Africa and the Comoros Islands, some whales represent a completely unique "Omani" genetic lineage.

The researchers detected, and often recorded humpback whale song throughout the survey period in the Kuria Muria Bay. Only the males sing, an activity that has been linked to breeding activity in other populations of this species elsewhere. As in previous surveys at this time of year, nearly every whale encountered seemed to be a singer. However the mother-calf groups that one would also expect to find on a breeding ground were absent. Future surveys will need to expand into other coastal areas of Oman and neighbouring countries to locate the areas used by females for calving and nursing.

Perhaps one of the most fascinating results of the limited encounters with humpback whales, were the photographs taken for individual identification. Of the six whales of which suitable photographs were taken, four were identified as whales that had been sighted on previous surveys. Some were identified from the distinctive features of their dorsal fins, while others were identified from the unique shape and patterns on the underside of their tail flukes.

The re-sights provide some very useful clues in the OWDRG’s attempt to unravel the puzzle of the whales’ seasonal movements, but more importantly the extremely high re-sight rate, may also be an indication that the population of humpback whales in Oman is very small, and therefore in greater need of protection than previously thought.

Other species observed during the survey include common dolphins (which, as their name suggests were commonly observed in large numbers throughout the survey area), Risso’s dolphins, and rough-toothed dolphins. This was only the third confirmed live sighting of this species in coastal waters of Oman, and most previous records are only of skeletal material or stranded specimens on beaches.

These sightings and observations will contribute to our understanding of cetaceans in Oman, and will help the OWDRG to work with relevant government bodies to protect and conserve their critical habitats. This survey, like others, also proved to be a valuable opportunity for cooperation on an international, regional and local level. The core team of OWDRG researchers was joined by Dr. Ken Findlay, an internationally renowned humpback whale biologist from South Africa and Andrew Willson, curator at the Kuwait National Aquarium. Their participation, which included an important element of training and knowledge exchange, was greatly facilitated by sponsorship from Oman Air and Emirates Airlines.

On a local level, the OWDRG was also joined and greatly assisted by staff from the Raysut Marine Laboratory, rangers of the Ministry of Regional Municipalities and Water Resources and from the Office of the Advisor for Conservation (Diwan of the Royal Court). The OWDRG sincerely hopes to further this cooperation and training in the areas where they conduct their research.

The OWDRG is an independent group of volunteer scientists, who rely entirely on support from local and regional sponsors for equipment, facilities and funding. This survey would not have been possible without the valuable assistance and contributions from the following organisations and businesses: The Ministry of Regional Municipalities, Environment and Water Resources; The Office of the Advisor for Conservation of the Diwan; Five Oceans LLC; Veritas Geophysical; Salalah Port Services; Shell Oman Marketing; PDO (and the PDO Dive Club); OHI Marine; Thuraya (distributor, Mustafa Sultan Telecommunications); the Marina Bandar Rowdha, the DG of Environment in Dhofar and the Hasik municipality, the Peter Scott Trust for Education and Research in Conservation and the Ford Environmental Grants.