DANA POINT, Calif.—Five miles off the coast aboard the Manute’a (pronounced mah-noo-tay-ah), a 50-foot catamaran sailboat with a group of 49 passengers spot two cow-calf gray whales breaching the Pacific Ocean’s surface, flip upside down and swim on their backs. A round of applause erupts from the passengers. “Wow! How cool is that?” says Captain Marie Clark of Captain Dave’s Dolphin & Whale Watching Safari. Both whales rolled back over. As they scale the surface, the mother blew out a heart-shaped spray of water from her spout before dipping back underneath the ocean—her tail reaching for the sky. “The whales have a lot of energy today,” Clark said. “We usually don’t see them raise their tail, especially when swimming only 50-foot waters.” After spending the winter in the lagoons of Baja, California—where the mother birthed her calf—the cetaceans are migrating northbound at about 10 miles per hour en route to …