Oyster farmers in New South Wales (NSW) have rescued three million baby oysters—each the size of a grain of sand—from catastrophic floods that have inundated northern NSW and Queensland since January. The farmers on the Macleay River, a major river in NSW, received the oysters just days before the floods, but heavy rains acidified the water, which can be lethal to oysters. As oyster shells are made of calcium, the acid can dissolve their shells or prevent the baby oysters from forming shells. The water condition was also not salty enough for the oysters. “They need saltwater to survive. The little ones won’t survive in that sort of water,” farmer Todd Graham told AAP. Graham and another oyster farmer drove the oysters an hour away to a nearby creek to keep them alive, but only after they were delivered to the National Marine Science Centre at Coffs Harbour, which has …