By MIKE ESTERL HOUMA, La.—Greg Voisin, an eighth-generation
oysterman, didn't like what he saw when he surveyed the rising
water from his boat in a bayou here. "It's like Mother Nature is
waterboarding us," said Mr. Voisin, operations chief at his
family's Motivatit Seafoods, one of the largest U.S. oyster
producers. Last year, Louisiana's harvest was cut in half to a
44-year low, as oil from the Gulf of Mexico spill and cleanup
efforts damaged oyster beds. For only the third time since 1950,
fewer than seven million pounds of oyster meat were hauled out,
and long-dominant Louisiana fell behind Washington state in
output. Now, the Mississippi River floods threaten to sink the
state's industry even further. To protect levees in Baton Rouge
and New Orleans, authorities recently opened the Morganza and
Bonnet Carre spillways, sending millions of gallons of fresh
water toward some of Louisiana's richest oyster grounds. Oysters
thrive on the bottom of coastal bays and swamps when the water's
salinity is about 15 p