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The establishment of the Tañon Strait as a protected area under the Expanded National Integrated Protected Areas System (ENIPAS) Act of 2018 is pivotal for the protection and conservation of its marine biodiversity and marine mammals. This decision was highly influenced by the study conducted by Dr. Louella Dolar of Silliman University in 1994 entitled “Incidental takes of small cetaceans in fisheries in Palawan, Central Visayas, and Northern Mindanao, Philippines” wherein the study documented several illegal fishing activities such as capturing and selling dolphins in the landing sites and in fish markets. The results of the study were very alarming as the cetaceans were part of the protected species stipulated in the Convention on International Trade of Endangered Species (CITES) as well as in the released Administrative Order no. 185 in 1992 by the Department of Agriculture (DA) through the recommendation of the director of Bureau of Fisheries and Aquatic Resources (BFAR).
Through the results of the study and by the recommendation of the Secretary of Department of Environment and Natural Resources (DENR), President Fidel V. Ramos promulgated Tañon Strait as a protected area by virtue of Presidential Proclamation 1234 of 1998 to further lawfully protect and conserve the marine habitat of cetaceans as well as its marine resources.
Yearly, a bi-annual Cetacean Survey is conducted by the TSPS - Protected Area Management Office (PAMO) to monitor the population of these marine mammals. This year, on June 24-29, 2024, the TSPS - PAMO led the survey and were participated by TSPS Site Management Units (SMU), Department of Environment and Natural Resource (DENR) - Region 7, Coastal Resources and Ecotourism Research Development and Extension Center (CRERDEC) and Philippine Coast Guard (PCG). The highlights of the survey results were the following:
A total of three (3) species of cetaceans were recorded during this survey - Grey Spinner Dolphins (Stenella longirostris), Risso's Dolphins (Grampus griseus), and Dwarf Sperm Whale (Kogia sima). The survey team encountered a challenge in identifying the Dwarf Sperm Whale as there is only a subtle difference between Dwarf Sperm Whale and Pygmy Sperm Whale (Kogia breviceps).
The team contacted Dr. Teri Aquino of University of the Philippines and Dr. Edna Sabater of Silliman University and forwarded the captured photos of the cetacean to help identify the species. Dr. Teri Aquino is hesitant on his identification and further contacted Dr. Dolar. The latter was also not sure of her identification however, she recalls observing a similar behavior projected by the Dwarf Sperm Whale during her survey in Tañon Strait so, she suggests that it is most likely that the species was of Dwarf Sperm Whale. Dr. Sabater on the other hand has no hesitation in identifying the species as Dwarf Sperm Whale and annotates that the photo reflects that the marine mammal is pregnant.
Moving forward, the survey has twenty (20) transect lines covering a total of four hundred and fifty (450) kilometers. The activity recorded a total of twenty-nine (29) sightings, twenty-seven (27) of them being Grey Spinner Dolphins that totals to a hundred and seventy-seven (177) individuals. The largest pod on-effort sighted consisted of seventeen (17) individuals. Dwarf Sperm Whales and Risso’s Dolphins on the other hand only sighted once and were observed in a pod of five (5) and seven (7) respectively.
The survey team also observed calving of Grey Spinner Dolphins in some pods as well as a pregnant Dwarf Sperm Whale as confirmed by Dr. Edna. The presence of calves and pregnancy in the pods of cetaceans signifies potential population growth and positive reproductive activities.
During the course of the activity, the team also annotated the presence of maritime traffic and fishing activities which may affect the survey’s encounter rate. This is attributable to the cetaceans having heightened senses and use of echolocation for navigation and communication, they tend to avoid areas with high maritime traffic.
There are eight (8) types of marine vessels recorded within the duration of the survey. The total number of observed vessels amounts to a hundred and sixty-one (161) within the duration of the survey. A hundred and thirty-three (133) of these were artisanal fishing vessels, nine (9) were of medium-sized passenger boats, eight (8) were of RoRo vessels, five (5) were of commercial fishing vessels, five (5) were of lite ferries, five (5) were of medium-sized tourist boats, and one (1) Barge.
Aside from the underwater noise caused by maritime traffic, other factors such as climate change, seasonality, changes in species composition over time, water pollution, marine heat-wave indices, and local threats may have significantly affected the survey's encounter rate. As the activity concludes, the TSPS-PAMO would like to reiterate that this survey is conducted to monitor the population of the cetaceans in TSPS which plays a crucial role as keystone species and a key indicator of the health of TSPS. With this, the office would like to remind everyone reading this article that it is imperative that we all take proactive steps in protecting and conserving our environment. By making environmentally conscious decisions, everyone can contribute to a cleaner and sustainable future for the welfare of all beings concerned.
