Joseph Geraci, a former top official of the National Aquarium in Baltimore, in 2002. (Amy Davis/Baltimore Sun)

Joseph R. Geraci, a scientist and veterinarian who was a leading expert in marine mammal medicine and aquatic wildlife conservation and a former official of the National Aquarium in Baltimore, died Sept. 10 at his home in Leesburg, Va. He was 77.

The death was confirmed by a former colleague, Mark Donovan. The cause was cancer.

Dr. Geraci was a professor in the University of Maryland School of Medicine’s Department of Pathology and was a proponent of teaching aquarium visitors about sea life and the issues affecting it.

In his four decades in the field, Dr. Geraci led research teams from the Arctic to the tropics to study the health of marine mammals and their environment.

He was born in Lawrence, Mass., and received bachelor’s and master’s degrees from Suffolk University in Boston and was a graduate of the University of Pennsylvania School of Veterinary Medicine. He earned a doctorate at McGill University’s Institute of Oceanography in Montreal.

After a teaching career at the University of Guelph in Ontario and Tufts University in Massachusetts, Dr. Geraci became the National Aquarium’s deputy executive director in 1997.

He also advised the International Whaling Commission and government agencies in Canada, Spain, Brazil and the United States.

At the time of his appointment in Baltimore, he said he wanted to make the aquarium’s visitors feel closer to the Chesapeake Bay.

He called the National Aquarium“the biggest classroom I’ve ever taught in.” He said that although he wanted aquarium patrons to have a pleasant visit, he also wanted them to learn something about the bay, its physics and its chemistry.

“There’s a lot we can do, because we have such a wide audience, to expose visitors to some of the exciting things happening on the bay, and to help them understand the role we all play in the health of the bay,” he told the Baltimore Sun in 1997.

Under his scientific guidance, the National Aquarium’s Marine Animal Rescue Program cared for numerous stranded animals, including turtles and pygmy sperm whales. Many were returned to their natural habitats.

Dr. Geraci had also been curator for the New York and Montreal aquariums and later served as president of the Mystic Aquarium in Connecticut from 2005 to 2006.

He was appointed to a National Academy of Sciences committee to study the effects on marine mammals of the 2010 Deepwater Horizon oil spill in the Gulf of Mexico.

Dr. Geraci wrote or co-wrote more than 120 journal articles, seven books and 21 book chapters.

He was the founding editor of the journal Marine Mammal Science.

Survivors include his wife of 10 years, Laurie Allen of Leesburg; three children from a previous marriage that ended in divorce; a brother; and six grandchildren.

— Baltimore Sun