The Crossroads Operation was an expedition to Bikini and the northern Marshall Islands in 1946 under the auspices of the Department of the Navy. Civilian scientists included staff from the US National Museum, Leonard P. Schultz, Curator of Ichthyology, and Joseph P. E. Morrison, Curator of Division of Mollusks. They studied the relative abundance of flora and fauna before and after the atom bomb tests. Specimens were collected for the purpose of comparison and to make possible a study of anatomical variations among the various island fish populations. The biological survey collected plants and animals on and around Bikini, Eniwetok, Rongelap and Rongerik Atolls.
Source:
Smithsonian Institution. (2013). Celebrating 100 Years : The Bikini Atoll Survey "Operation Crossroads," 1946-47. Retrieved on from http://www.mnh.si.edu/onehundredyears/expeditions/bikini.html