PORTSMOUTH, N.H. — Federal officials say the number of dead harbor seals found on beaches in New Hampshire, Maine and Massachusetts in the past several weeks is nearing 100, yet the cause remains a mystery.

Mendy Garron, regional marine mammal stranding coordinator for the National Oceanic and Atmospheric Administration, said Thursday the count is now up to 94 since Sept. 1.

Most of the dead mammals are considered young.

Biologists are awaiting results of necropsies to determine a cause.

Investigators have ruled out foul play and lack of food, and are focusing on determining whether disease is the cause.

A spokesman for the New England Aquarium tells the Portsmouth Herald (http://bit.ly/qfN9RC ) biologists have sent samples of tissue, blubber, muscles and almost every organ for testing.

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