خرچنگ‌های آبی چساپیک پس از سال‌ها کاهش، بازگشتی غیرمعمول داشتند. دانشمندان نمی دانند چرا

Chesapeake blue crabs had an unusual rebound after years of decline. Scientists don't know why

After half a decade of worryingly low numbers, the Chesapeake Bay's blue crab population appears to be fighting its way out of a slump. Scientists still have no clear explanation for why, and say the growth deserves cautious optimism.