The company developing a $180 million Atlantic salmon farm in Bucksport has redesigned some of its construction plans so a building and road steer clear of the remains of a 19th-century farmstead found during an archaeological survey in September. The results of the survey confirmed the presence of the farmstead — specifically, a stone-lined cellar hole, said Arthur Spiess, chief historic preservationist for the Maine Historic Preservation Commission. Whole Oceans, the company behind the Atlantic salmon farm, hired a contractor to conduct the survey after a local, amateur historian, Emeric Spooner, raised concerns that some aspects of local history would be lost from the development, said Susan Lessard, Bucksport’s town manager. In response to the findings, the company will change the planned locations of an auxiliary building and an access road.