Marie "Bobbie" Dennis Poland Fish (1900 – February 2, 1989) was an American oceanographer and marine biologist known for her bioacoustics research and the finding of eel eggs in the Sargasso Sea.

Her research on underwater sound detection allowed the United States Navy to distinguish enemy submarines from wildlife.

The United States Navy awarded her its highest civilian award, the Distinguished Service Medal, in 1966 to recognize her contributions during her twenty-two years (1948–1970) leading the "Underwater Sound of Biological Origin" project for the Office of Naval Research.

[12] In a 1926 article in Science she first describes the collection of the eggs and their development into what she was able to identify as an American eel.

[14] She concludes her initial description by noting that...the sea has given up the last secret concerning the life history of the American eel which it has jealously guarded for so many centuriesFish's publications include work cataloging sounds from marine animals, including from fish[15][16] and whales.