The National Marine Fisheries Service is investigating the death of two dolphins found washed ashore in California shortly after Navy ships were using sonar in nearby waters.

Agency spokesman Jim Milbury said Wednesday the animals are being analyzed to try to determine what caused them to get stranded.

Navy spokeswoman Lt. Julie Holland says the dolphins were common bottlenose dolphins. They were found Oct. 21 at Imperial Beach and at Silver Strand beach in San Diego.

Holland says two Navy ships were using mid-frequency active sonar 80 nautical miles away from where the dolphins were found. They used the sonar for slightly more than an hour over two days from Oct. 19.

Sonar can disrupt marine mammal feeding and communication from a great distance. It can cause deafness or death when closer.

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