this idyllic estuary several hundred kilometers from the senegalese capital dakar is lined with mangrovesprovide nesting grounds for several kinds of fish -- and for oysters. the women have just a few hours to finish their work before the tide comes in. seynabou says that, for years, the villagers chopped the mangrove roots to get at the oysters. but in doing so, they destroyed the very foundation of their livelihood. the method they use now is no less work, but it's more sustainable. after about a half hour's walk, they come to the oyster bed. it's 40 degrees celsius in the shade and humid -- an ideal climate for oysters. the larvae attach themselves to the shells and grow. >> now we've finished hanging up the new strings. the work we do here isn't easy -- it's really very hard work. we don't have the right clothes or footwear. here you see. i cut myself on the sharp edges of the shells. >> they do what they must to make a living. the smaller oysters are put in net sacks and kept wet until they mature. >> this was a good harvest. the little oysters are especially delicious. >> it takes f