Hugh Hamilton DeWitt (28 December 1933 – 5 January 1995) was an American ichthyologist, marine biologist and oceanographer.
His surname at birth was Seligman but at his father's urging he and his brothers changed their name to DeWitt in the 1950s, a name from their mother's side of the family, as they had encountered mistaken preconceptions while attending High Schools in the eastern United States.
[1] DeWitt was known internationally as an ichthyologist, marine biologist and oceanographer with a special interest in the taxonomy, functional morphology, biogeography and ecology of fishes, particularly the species which inhabited the frigid waters of the Southern Ocean.
In 1975 he was the chief scientist on the Argentine naval research vessel ARA Islas Orcadas and he was frequently invited to participate in other cruises as his technical expertise was highly regarded.
He named a number of species, particularly from Antarctica and was a major contributor to the book Fishes of the Southern Ocean.