ملف:Hon. Marshall McDonald.jpg

English: Marshall McDonald (October 18, 1835 – September 1, 1895) was an American engineer, geologist, mineralogist, and fisheries scientist. McDonald served as the commissioner of the United States Commission of Fish and Fisheries from 1888 until his death in 1895. He is best known for his inventions of a number of fish hatching apparatuses and a fish ladder that enabled salmon and other migrating fish species to ascend the rapids of watercourses resulting in an increased spawning ground. McDonald's administration of the U.S. Commission of Fish and Fisheries was notably free of scandal and furthered the "protection and culture" of fish species throughout the United States.