During a lower-than-usual tide this summer, the rocks on the beach were exposed on Southeast Alaska’s Chichagof Island. Ralph Wolfe went down to the shore to help young people — participants in Hoonah Culture Camp — harvest traditional Alaska Native subsistence foods. Together, they pried tasty mollusks, called gumboots, off rocks and filled plastic buckets with slick bull-kelp and bright green sea asparagus.