A large pod of dolphins proved to be an unexpected spectacle for tourists taking a boat trip near San Diego, California.

Marine mammal expert Sarah Wilkin said the dolphins may have been there because of an abundance of food in the area, including sardines, herring and squid.

She said they typically travel in groups of 200 or less, but "super-pods" were not unheard of.

These pictures were captured by one of the boat's passengers, Victor Morassi.