A toxic algae bloom is believed to be behind the overwhelming numbers of severely sickened marine mammals.
A $20,000 (£15,419) reward is being offered to anyone who can help solve the case.
The dolphins were spotted and filmed off the coast of southern California. The boat owner estimated more than 100 dolphins were there.
WWF is tracking pink river dolphins in the Amazon using satellite technology after scientists successfully tagged six river dolphins in Brazil, Colombia and Bolivia.
The mammal is thought to be part of 'famous Moray family'.
The perfect way to take a break from whatever you are doing.