Hundreds of fish have been found dead in Manila Bay, the Philippines and experts believe a reduction in oxygen levels to be the cause.

Footage filmed on September 18 shows several fish carcasses floating amongst plastic pollution in the bay.

The Bureau of Fisheries and Aquatic Resources conducted tests on the water quality in the Baseco area and revealed it had very low levels of dissolved oxygen.

The Department of Environment and Natural Resources (DENR) Undersecretary Benny Antiporda dismissed claims that artificial white sand, white dolomite, on the shoreline was the cause.

Antiporda, who conducted an inspection on the site, said water samples from the area were already obtained and laboratory tests are being done.