A narrow passage of water between Cebu and Negros Islands, Tañon Strait is renowned worldwide for its rich marine life. It is home to numerous cetaceans, including 15 species of dolphins and whales. However, recent findings suggest that the populations of these marine creatures are on a fast decline.
We encountered only between 80 and 90 individual spinner dolphins throughout our four-day survey. This is in stark contrast to surveys in previous years, where we might spot as many as 100 individuals in just one day.
Tañon Strait, designated as a protected seascape in 1998 under Presidential Proclamation 1234, has been a sanctuary for a diverse array of marine species. A popular destination for ecotourism, particularly dolphin and whale watching, the strait has attracted numerous visitors eager to witness these remarkable animals in their natural habitat.
I spearheaded the survey from July 20 to 23, focusing on dolphin populations within the southern part of Tañon Strait. The initiative revealed deeply concerning trends, such as a decrease in dolphin numbers, a reduction in species diversity, and evasive behavior possibly linked to increasing human activity in the area.
In the past, these surveys witnessed vibrant gatherings of diverse species of cetaceans — including numerous kinds of dolphins and species of whales, with groups of as many as 100 individuals spotted in a single day. However, the recent survey was starkly different, showcasing only three species: spinner dolphins, common bottlenose dolphins and dwarf sperm whales.
Of particular concern was the notably evasive behavior of the dolphins, a possible sign of stress or disturbance due to the persistent presence of aggressive dolphin-watching boats. My team and I, who have been monitoring the region since 1997, noted a significant increase in the number of dolphin-watching boats, even notwithstanding the destruction caused by super typhoon Odette in 2021.
The area now hosts around 60 boats, down from the original 260. Nevertheless, I fear that this may still be too much: Too many dolphin watching boats in the area disrupts the cetaceans’ habits.
I also warn against the overutilization of the area’s resources. There should also be a comprehensive assessment of fisheries resources in the entire Strait as there is clearly less food now for these creatures.