Orca Pair and Calves Sighted at Pulau Sipadan 'Encouraging' For Scientists
Marine biologists have been encouraged by the sighting of four orcas at Pulau Sipadan in Sabah, Malaysia last month, saying the encounter highlighted the importance of the Semporna region for marine mammals, and provided valuable data for ongoing cetacean studies in the area.
Footage of the encounter posted on social media by DIVE's 2020 Travel Awards-winning dive operator, Scuba Junkie, showed two adult orcas and two calves swimming to the north of Sipadan. One of the adults was seen ‘lobtailing' – splashing the surface of the water with its tail – which is thought to be a form of communication between orcas, and perhaps in this case, a warning to stay away.
Orca sightings, often associated with cooler waters and more temperate latitudes, are not uncommon in Semporna – the region has been identified as a key part of the Western Celebes Sea Drop Off ‘Area Of Interest’, as designated by the IUCN Marine Mammals Protected Areas Task Force, due to the high number of marine mammal sightings that have been reported in the area.
To date, 21 species of mostly pelagic and deep-water marine mammals have been recorded in the region. Some species, such as the melon-headed whale, are thought to be quite populous, but encounters with humans are rare and much of their life cycle remains elusive to humans. Their presence in the Semporna region presents a unique opportunity for researchers to learn more about these enigmatic species, and the regular sightings of orcas, sperm whales and other pelagic mammal species migrating through the nearby Sulu and Celebes Sea marked the region for closer scientific study.
'It is not unusual for our guests to see marine mammals on their way to Sipadan or on the south side of Kapalai,' said Arapat bin Abdurahim, a divemaster at Scuba Junkie's Sipadan dive centre. 'Quite often, it is dolphins – but on other occasions, we are treated to rarer species such as the orcas sighted last week, melon-headed whales and even sperm whales.
'It is incredibly exciting for guests and staff to spot a marine mammal on the surface and be able to contribute to the body of research on rarely seen species,' said Arapat, 'for example, in 2017, when we reported the first confirmed sighting of dwarf sperm whales in Malaysia.'
Scuba Junkie S.E.A.S, the marine conservation organisation based at Scuba Junkie’s Mabul Beach Resort, in partnership with the Society of Marine Mammalogy (SMM) and Malaysian NGOs, has been working with researchers to collect data on the whales, dolphins and porpoise that are present in the region.
'This is not the first time we have seen an orca with a calf in this area,' said David McCann, Conservation Manager for Scuba Junkie S.E.A.S. 'There was an incredible encounter when divers with Scuba Junkie witnessed an orca and calf eating a sunfish in 2019. Examining whether this area has an important role for mothers and calves would be of great interest to many parties.'
'For many of the marine mammal species seen in the Semporna region, their use of the area is still unknown,' said Dr Lindsay Porter of the SMM awards committee. 'It may be seasonal, to fulfil critical aspects of lifecycle patterns, for example, shelter for mothers and young calves – such as the orca last week – or transient, as part of a migration route or larger oceanic passages.'
Semporna's dive operators have also assisted the research by deploying acoustic monitors on the seabed, in order to record marine mammal vocalisations, from which species identification can often be made.
'The use of acoustics as part of this project has allowed us to more consistently monitor the area, meaning that species identification does not solely rely on opportunistic sightings,' said Dr Porter. 'The acoustic recordings provide us with a detailed soundtrack of marine mammal vocalisations, which will provide us with a more detailed picture of how the mammals use this area.'
'We are also greatly looking forward to finding out what sounds have been recorded underwater, by animals that were perhaps not seen,' said McCann. 'It is fascinating to think about what else may be out there.'
'Reporting sightings is vitally important to the success of these projects,' said Dr Porter. 'The partnership with Scuba Junkie S.E.A.S has enabled training to be given to local dive operator staff, so we now receive good imagery and clear descriptions from such encounters.
'As always, we urge caution and care in these encounters,' added Dr Porter. 'Please behave responsibly around all marine animals, do not get too close to animals or harass or stress them to get footage. I applaud the divemasters at Scuba Junkie for their care and attention in their encounter with the orcas, keeping their distance and not entering the water because they could see two calves, rightly surmising that the adults could be protective of the young. It is quite possible the ‘lobtailing’ seen was a warning to the boat not to get too close.'