Her father, Charles Clark, died when Eugenie was almost two years old, and her mother, Yumico Motomi, later married Japanese restaurant owner Masatomo Nobu.

During summers, she studied at the University of Michigan Biological Station, and prior to graduate school, she worked for Celanese Corporation as a chemist.

Eugenie initially sought to attend graduate school at Columbia University, but her application was rejected out of fear that she would eventually choose to leave her scientific career in order to focus on raising children.

After completing doctoral research, Clark received a Fulbright Scholarship to pursue ichthyological studies at the Marine Biological Station in Hurghada, on the northern Red Sea Coast of Egypt.

[1] After Clark delivered a presentation on Red Sea fish, the attendees revealed that they had encountered many similar animals in local waters and were interested in learning more about them.

[7] At the Cape Haze Marine Laboratory, Clark worked with a local fisherman named Beryl Chadwick, who was experienced in catching sharks.

On these dives, Clark often utilized the glass jar catching technique popularized by Connie Limbaugh, then the Chief Diver at Scripps Institution of Oceanography.

In 1962, Clark participated in the Israel South Red Sea Expedition, which set up a camp on one of the Eritrean islands of the Dahlak Archipelago.

Clark officially retired from the University of Maryland in 1999 but taught one class in the zoology department each semester for several years.

She worked there as Senior Scientist, Director Emerita, and Trustee until her death in Sarasota, Florida, of lung cancer on February 25, 2015.

[5] Clark was married five times, the first four ending in divorce: Jideo Umaki from 1942 to 1947, Ilias Themistokles Konstantinu from 1950 to 1967, writer Chandler Brossard from 1967 to 1969, and Igor Klatzo in 1970.

Publications from within this body of work document that she was the first person to train sharks to press targets,[12] as well as the first scientist to develop "test tube" babies in female fish.

In 1975, she received the Gold Medal of the international Society of Woman Geographers for her studies of shark reproduction and behavior.