The study presents results from photographic images of 152 individual whale sharks collected by the researchers from Large Marine Vertebrates Research Institute Philippines over a period of 34 months (March 2012 – January 2015) in Oslob, Cebu. The team used photo-identification (photo-ID) to monitor individual whale sharks’ presence and movement and gathered data on the presence, size, type and location of scars on the whole body of these gigantic animals as well as the accumulation of these scars over time. These scarring patterns of whale sharks in Oslob were compared with quantitative studies from Ningaloo in Australia, the Seychelles and Mozambique, other known global aggregations where feeding the whale shark is prohibited and enforced.

The study found that whale sharks in Oslob were significantly more scarred than any other studied population: 95% of all whale sharks in Oslob had scars on their body, with abrasion being the most common type of scar. Most of the scars were categorised as nicks and abrasions and were most likely due to the close contact of ropes, small boats at the provisioning site. Lacerations, which fall into the major category, were observed on 28% of individuals, which is significantly higher than in Ningaloo and Mozambique. These were caused by boat propellers of different sizes and could be facilitated both from the habituation to boats caused by the practice of hand-feeding the whale sharks, as well as the increased traffic of motorized vessels in the surroundings of the provisioning area.

Whale sharks that were observed more frequently in the interaction area showed a significantly higher rate of scarring compared to individual sharks that were seen less frequently in the area; these regular visitors to Oslob accumulated scars over the observation period and suggest a direct causal link between the exposure to the tourism activities in Barangay Tan-Awan and scarring rates. Scars and wounds, even when non-lethal, may pose a serious risk to these endangered species, increasing the physiological stress of the animals, facilitating the contraction of diseases carried by pathogens like virus and bacteria and decreasing overall the health of the affected individuals.

Scars on the head and mouth of a whale shark in Oslob, Cebu at different stages of inflammation and tissue reaction. These scars are caused by continuous contact and rubbing against hard surfaces like outriggers and boat hulls, and are similar to what observed in whale shark kept in captivity in aquaria. Credit: ©LAMAVE

“This study presents evidence of the negative physical impacts of the tourism activity on the whale sharks in Oslob. I have seen myself the wounds on these endangered and enigmatic animals; injuries which highlight the need for an urgent change in Oslob.” – Lead author Luke Penketh

Management solutions to reduce the physical impact of tourism on whale sharks

The high incidence of injuries in the whale sharks provisioned in Oslob is a national concern and there is an urgent need to improve management practices to protect this endangered species. The whale shark is protected by Republic Art No. 9147 ‘Wildlife Resources Conservation and Protection Act.’ whereby it is illegal to maltreat and/or inflict injuries on threatened wildlife, and this is further reinforced by the DOT-DA-DILG-DENR Joint Memorandum Circular no.01 series of 2020 (Sect. 8) where it prohibits acts in dedicated interactions sites that would hinder an animals’ health, including injury and distress.  The Philippines is a signatory country to the UNEP Convention on Migratory Species (CMS), where the signatories agree and recommend the strict regulation, monitoring and enforcement of the whale shark tourism interaction activities to ensure its sustainable management and conservation value as highlighted in the Concerted Action for the Whale Shark (UNEP/CMS/Concerted Action 12.7, 2017).

The results highlighted in this study, when paired with the existing knowledge on the migratory nature of this species and connectivity between the archipelago, where individual whale sharks identified in Oslob have been re-sighted in Donsol (Sorsogon Region V) Sogod bay (Southern Leyte Region VIII), Tubbataba Reef Natural Park (Palawan Region VIa), Misamis Oriental (Region 10) and nationally connected further abroad to Malaysia, Indonesia and Taiwan, call the National  Department of Tourism, Department of Environment and Natural Resources and the Department of Agriculture –  in collaboration with the Department of Interior and Local Government to urgently intervene to ensure the sustainable management the tourism activities in the municipality of Oslob, as well as in other Regions, to ensure the long term balance between the socio-economic benefit of the local communities, the conservation of the marine environment and preservation of endangered protected species like the whale sharks.

For more information about the work of LAMAVE visit the website by clicking here.