he redfish cruised the edge of the reeds, unhurried and unalarmed. The U-shaped push of the big blunt head was coming straight toward our flats skiff. I was in the right place at the right time. Only one person could screw this up now. I roll-cast the crab fly from the palm of my hand, backcast once, and lay the fly against the marsh bank. I wince—the pattern lands a little short. “That’ll work,” says my guide, Michael Evans. “Leave it.” The fish stays the course, 10 feet from the fly and closing. Play this right, I think, and this could be as perfect as it gets when it comes to casting for Louisiana redfish. “Now,” Evans commands. I strip-set the fly, and line rips from the reel as the redfish bolts across the shallows. I whoop as the fish surges three times before Evans hauls it overboard, and all is as it should be—green marsh, blue sky, and a redfish in hand. It is a gorgeous morning in one of the most iconic sporting landscapes in America. But the worry is, it could all be falling apart in south Louisiana. I was so focused on the fish that I initially missed a few significant details: The marsh edge here is corroded and eroding, with chunks of black muck and reeds calving into the open water. Dotting the shoreline are posted signs, and I can see that the only other boat out here is working over ponds deep in the marsh interior. Those anglers are most likely trespassing, although they don’t know that—or do and don’t care.