Friday, August 25, 2023

Let's Save the Endangered Giant Clam (Tridacna gigas)

 Let's Save the Endangered Giant Clam (Taklobo)* 

Dr Abe V Rotor
Living with Nature School on Blog [ avrotor.blogspot.com ]*
Former Professor, UST Graduate School
Author and his students lift a living specimen of the Giant Clam 
(Tridacna gigas) from its natural habitat during an on-site study
off the coast of Masinloc, Zambales.
 

A seven-kilogram Tridacna gigas is examined by students in 
Environmental Science from the UST Graduate School

Natural habitat of taklobo at 6 to 14 feet on coral reef 
of San Salvador Island, east of Masinloc, Zambales.

Facts about the giant clam, Tridacna gigas.

1. In the Philippines it is called taklobo. It is the largest living bivalve mollusk and one of the most endangered clams.

2. It lives on shallow coral reefs of the South Pacific and Indian oceans, up to 20 meters deep.

3. It weighs more than 200 kilograms (440 pounds), and measures as much as 1.2 m (4 feet) across. It has an average lifespan in the wild of 100 years or more.

4. Although larval clams are planktonic, they become sessile in adulthood. Growth is enhanced by the clam's ability to grow algae in symbiosis. The creature's mantle tissues act as a habitat for the symbiotic single-celled dinoflagellate algae (zooxanthellae) from which it gets its nutrition. By day, the clam opens its shell and extends its mantle tissue so that the algae receive the sunlight they need to photosynthesize.

5. T. gigas reproduce sexually. They are hermaphrodites (producing both eggs and sperm), but self fertilization is not possible. Since giant clams can't move across the sea floor, the solution is broadcast spawning. This entails the release of sperm and eggs into the water where fertilization takes place.

Let's save the giant clams. It's better to be assured they are alive on the seafloor than to have their fossils in our home.~

 
Tridacna in its natural habitat - lighted seafloor.  Right, Tridacna graveyard. 
Shell is highly prized for locally and for export.  Collection and selling 
of Tridacna shell is strictly prohibited. 

 
Mrs Cecilia Rojas Rotor, author's wife. poses before a giant Tridacna shell as holy water receptacle in Mount Carmel Church, QC
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*Why are giant clams endangered in the Philippines? Giant clams, which can weigh up to 200kg and live for more than a century, face an existential threat from illegal poaching – and very likely organized crime – which has spiked in the last few years across Philippine and Indonesian waters, conservationists have warned. Internet Apr 26, 2023

References: Living with Nature by AVRotor; Marine Biology: An Ecological Approach by JW Nybakken; Wikipedia.

 Lesson on former Paaralang Bayan sa Himpapawid with Ms Melly C Tenorio 738 DZRB AM Band, 8 to 9 evening class, Monday to Friday

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