Conservation researchers aboard a ship off Point Reyes recently spotted a whale so rare that experts estimate fewer than 50 remain in United States waters. The endangered North Pacific right whale was observed resting near the Cordell Bank National Marine Sanctuary on May 24. “This whale was observed for 20 minutes and had a distinctive V-shaped blow, a black body, at least one cluster of white callosities on the head, and no dorsal fin,” the…