Jonathan Grant, an oceanographer and outdoorsman, died of leukemia Sept. 12 at a hospital in Nova Scotia. He was 69.

Dr. Grant, Jon or Jonny to friends, was born in Baltimore to Albert and Sara Jane Grant. His father was a heart doctor, and his mother was a nurse. He grew up in the Cross Country neighborhood in the city’s northwest corner as the third of four brothers with a German shepherd named King.

As a teenager, Dr. Grant took care of an aquarium of tropical fish and played in the Western Run stream behind his house and in bands with friends. Richard Edlow, his lifelong best friend, said Dr. Grant saw Jimi Hendrix at the Baltimore Civic Center in 1970, and he grew up to be happiest with a guitar by a campfire.

“We did a lot of camping,” Dr. Edlow said. “He always had a guitar in his hand.”

Dr. Grant loved The Beatles and the Allman Brothers. He graduated from Baltimore Polytechnic Institute in 1972 and Duke University with a bachelor’s degree in zoology in 1976. He earned a Ph.D. in biology from the University of South Carolina in 1981 and later that year started a postdoctoral fellowship at Dalhousie University in Nova Scotia in northeastern Canada, where he earned tenure and stayed for over 30 years.

His wife, Janet Salo, said his first research projects were about scallops and mussels before he started to scuba dive to study fish.

The two met on a cross-country skiing trip, married in Nova Scotia in 1989 and have two children, Jasper and Jacy.

“We didn’t date like normal people. We went camping,” Janet Salo said.

Over his career Dr. Grant became a leading international expert in aquaculture, the practice of raising and harvesting fish, shellfish and aquatic plants in a controlled environment. He published more than 200 scientific papers and articles, mentored hundreds of students, and traveled the world.

At home around Wellington, Nova Scotia, Dr. Grant entered dogsled races and spent summers backcountry hiking and camping out of a Volkswagen Westfalia van. Daughter Jacy Grant, 21, nearly qualified for the 2024 Paris Olympics in sprint canoe and plans to qualify for Los Angeles in 2028. She won silver in the 1,000-meter race at the 2023 world championships in Duisburg, Germany.

“We had double kayaks when the kids were really young and were just always at lakes renting canoes,” Janet Salo said.

Dr. Grant returned to Baltimore once a year to visit the aquarium and catch a baseball game.

“Jon went on to incredible success, just amazing professional success, and he always had this piece of his heart in Baltimore,” Dr. Edlow said. “He always had his roots in Baltimore.”

Dr. Grant is survived by his wife, Janet, of Wellington; his son, Jasper Grant, of Halifax, Nova Scotia; his daughter, Jacy Grant, of Halifax; and his brothers Freddie Grant, of Delaware; and Sam Grant, of Baltimore.