The beaches were still open; the restaurants were still serving shrimp. Fishermen were still casting for whiting off the white sandy shores. And ads on television still proclaimed the region open for business. But as the oil slick made its way inexorably here toward the barrier islands at the mouth of Mobile Bay, with forecasts for a swath from Mississippi to the beaches of Pensacola, Fla., later this week, the mood was of the last days. 'You guys are our first line of defense,' Casi Callaway, executive director of Mobile Baykeeper, a conservation group, told about 50 volunteers gathered in a room filled to capacity. 'Your job is to document what we have here that's beautiful. BP will have to make it right.' They had come to train as field observers, taking photographs and notes on the conditions of the shoreline before the oil arrived. Now, suddenly there was an urgency to their preparations. Over the weekend, isolated tar balls had washed ashore on nearby Dauphin Island, interrupting a busy beach holiday. 'It's starting,' Callaway said. 'The first groups today took beautiful pictures of the western shore of Mobile Bay. But there are fish kills everywhere. One of our friends was on Dauphin Island when the tar ball washed up. Her 12-year-old daughter just started crying.' On the west end of the island, Laura Bishop sat in the sun with her two daughters, on a beach otherwise empty except for haz-mat cleanup patrols in rubber gloves and yellow rubber boots duct-taped to their pants. 'The beach looks good and it's beautiful,' she said as her daughters played in the water. 'To sit here and see these people come here is scary.' Nearby, National Guard troops filled wire-framed sand barriers at the shoreline to block oil from reaching the shore, and backhoes created 12-foot mountains of sand in case hurricanes add to the misery. The island lost more than 100 houses to Katrina. Though the state Department of Public Safety closed the beaches for fishing, a few people fished anyway. Just a few days ago, some people here had hoped that the winds and currents would move the oil away from Alabama's coastal islands. 'I had townspeople calling me and saying it's not coming here,' said Grace Tyson, who runs Tyson Realty on Dauphin Island, shaking her head. 'People said, 'Take my condo off the market.'' Business is down by more than 75 percent, she said. And with the latest forecast, she added, 'I'd say closer to 100.' On the coastal island of Gulf Shores, some residents who had seen tar balls near their property said that neighbors had told them not to talk about it. Callaway said that after she talked on television about the tar balls on Dauphin Island, she, too, had received angry responses. 'I had people telling me, 'Thanks a lot, you killed our tourist season.'' Fishermen and businesses have already put in claims with BP and the state for lost revenue, though the big losses are yet to come, said Jeanine Stewart, an owner of Burris' Farmers Market in Loxley. 'The big thing businesses want to talk about is government supplements or BP claims,' Stewart said. 'They've advised all of us to file claims.' Betty Edwards still has hope, but it is dwindling. Edwards and her husband have owned homes on Dauphin Island since 1978, and returned even after two were destroyed by Hurricanes Frederick and Katrina. She said she was still eating local seafood five days a week. 'My mother is sick and I should be with her,' she said, mentioning Alzheimer's. 'I said, 'I'm going to stay here until it's all closed.' It could be a couple days. But it's when, not if.' 