Marine Turtles
With its abundant coral reefs, seagrass beds, and almost 37,000km of coastline, the Philippines is home to five out of seven species of marine turtles. There have been sightings of loggerhead and leatherback turtles in Philippine waters, but the following three species have also confirmed nestings in the country: the green turtle, the hawksbill turtle, and the olive ridley turtle, which are presented below. All three species nest on Dahican Beach, which is quite rare. We are proud to have such a great turtle diversity! Even leatherback turtles have been reported by fisherfolks and the Amihan team also saw them in Dahican Bay, but there are no records of nestings.
Ecological Role
With the important ecosystem functions marine turtles perform, such as maintaining the health of seagrass areas through grazing, and thus ensuring a proper habitat for juveniles of commercially important fish species, maintaining the health of coral reefs by foraging on algae, improving the nutrient cycling on beaches through the egg shells that are left behind after the hatchlings emerge, maintaining balanced food webs, e.g. leatherback turtles keeping the jellyfish populations in check as these are their favourite food etc., they form an integral part of coastal and marine ecosystems. However, all marine turtle species are facing numerous threats due to unsustainable, destructive, and illegal fishing practices, poaching of turtles and turtle eggs, light pollution, boat strikes and more. Coupled with a late sexual maturity (on average about 20 years) and a low survival rate from hatchling to adult (1 in 1,000), population numbers can easily be affected by the right or wrong management actions. Also, the results of these action can often be seen only many years later, once the hatchlings return as adults to their natal beach to nest themselves. That is why marine turtle conservation is now more important than ever, and groups that have been trained by the DENR-BMB, such as the Amihan sa Dahican-SOS, are contributing significantly to turtle protection.
For more information on how to distinguish the different marine turtle species, please have a look at the Queensland Marine Turtle Field Guide, which provides very helpful information.
With the important ecosystem functions marine turtles perform, such as maintaining the health of seagrass areas through grazing, and thus ensuring a proper habitat for juveniles of commercially important fish species, maintaining the health of coral reefs by foraging on algae, improving the nutrient cycling on beaches through the egg shells that are left behind after the hatchlings emerge, maintaining balanced food webs, e.g. leatherback turtles keeping the jellyfish populations in check as these are their favourite food etc., they form an integral part of coastal and marine ecosystems. However, all marine turtle species are facing numerous threats due to unsustainable, destructive, and illegal fishing practices, poaching of turtles and turtle eggs, light pollution, boat strikes and more. Coupled with a late sexual maturity (on average about 20 years) and a low survival rate from hatchling to adult (1 in 1,000), population numbers can easily be affected by the right or wrong management actions. Also, the results of these action can often be seen only many years later, once the hatchlings return as adults to their natal beach to nest themselves. That is why marine turtle conservation is now more important than ever, and groups that have been trained by the DENR-BMB, such as the Amihan sa Dahican-SOS, are contributing significantly to turtle protection.
For more information on how to distinguish the different marine turtle species, please have a look at the Queensland Marine Turtle Field Guide, which provides very helpful information.
Dugongs
Dugongs, or sea cows, are marine mammals of the order Sirenia. They prefer shallow waters near the coast, are often found foraging in seagrass areas and used to be a common sight in Philippine waters. However, boat strikes, entanglements, and opportunistic taking have decimated population numbers. They are migratory animals, even though they show site fidelity, and can cross open seas. Dugongs can grow up to 70 years of age and, like marine turtles, they have a slow reproduction rate – with one calf every 3-7 years – which makes proper conservation management a priority. Dugongs have been sighted regularly in Mayo Bay, which, with its extensive seagrass areas, is one of the places these animals call their home and we were able to observe them on numerous occasions.
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Cetaceans, Sharks & Rays
Cetaceans comprise different species of whales and dolphins and there are about 29 species present in the Philippines. Dolphins are often sighted in Mayo Bay, especially Spinner dolphins, which can be observed swimming playfully in the water from the shore, the fishing boats, or even sitting on a surf board. If we're lucky, we also get to see pilot and sperm whales, who occasionally swim by.
We have also sightings of the famous whale sharks here in the bay, which we call butanding, a filter-feeding carpet shark, migrating along the southern Philippine shores from July-October. They can grow up to 18m of length and are beautiful animals with countless white dots on a dark grey to black background. Another beautiful filter-feeder sighted in the bay is the manta ray. The span of their fins can reach from 5-7m, and whereas their dorsal part (back) is black, their ventral part (underside) is white. This allows the manta to camouflage itself, as it blends with the water when seen from above, and it merges with the water surface and the sky when viewed from below, shielding it from predators. As for marine turtles and dugongs, boat strikes, entanglement and poaching – for their fins – can impact negatively on the populations. |