Complex sentence: First photographed from the air by U.S. Navy Operation Highjump, 1946--47, it was included in a 1957 survey of the Swain Islands by Wilkes Station personnel under Carl R. Eklund.
Split into simpler sentences: First photographed from the air by U.S. Navy Operation Highjump, 1946-47. It was included in a 1957 survey of Swain Islands by Wilkes Station personnel under C.R. Eklund.