Shellfish are some of the most nutritious foods in the world. It is unfortunate though that recent civilization pollution has caused and continue to cause red tide poisoning. I myself have been helped twice by raw live oysters for fertility and for retinal detachment. My wife was helped with her B12 deficiency be eating live clams. So it is vital for us to know when and where are oysters, clams and mussels safe to eat.
Enter the Bureau of Fisheries and Aquatic Resources. This government agency at http://www.bfar.da.gov.ph is in charge of testing the food all around the country. They post weekly bulletins in the newspapers, but you may find it more convenient to check on their website at the left column it says RED TIDE UPDATE.
As of this writing http://www.bfar.da.gov.ph/news/redtide_update%2811032010%29.html is the most current update in their website, although I did see in the newspapers they have a new update November 5, 2010.
So it seems my oyster sources at Bolinao, Pangasinan and Obando, Bulacan are red tide free. I can vouch for that because we just ate a good amount of oysters Saturday and last Thursday and we all feel fine.