The beginning of the herring spawn in Sitka Sound signals the wind-down of commercial fishing, and the start of the subsistence harvest: The millennia-old tradition of submerging hemlock branches along the shoreline, and waiting for herring to coat them in a thick layer of eggs. And one subsistence advocate who’s determined to see this tradition continue — by working to protect herring stocks, and by teaching kids how to harvest eggs . “This was their first time seeing what subsistence herring