John Racanelli, the longtime president and CEO of Baltimore’s National Aquarium who has spearheaded conservation efforts and pushed to build a dolphin sanctuary, is retiring “by the end of the year,” aquarium officials said.

As part of a “planned leadership transition,” Jennifer Driban, who is the aquarium’s chief mission officer, will become interim president and CEO when Racanelli leaves, the aquarium said in a press release Thursday morning.

Racanelli said that after his retirement, he will work to develop a dolphin sanctuary — a project he first announced with the National Aquarium in 2016.

He said he will continue the dolphin sanctuary work independently and collaborate with aquariums around the country that need to find homes for cetaceans living in captivity. It was not immediately clear if the aquarium would continue its own sanctuary project.

The dolphin sanctuary has been a lengthy project that would be the first of its kind. Some scientists have questioned whether such a sanctuary would benefit sea life. Racanelli said there is a “huge demand” for relocating thousands of captive dolphins.

Racanelli said he had been planning his retirement since signing his third five-year contract in 2021. That contract was supposed to be up in June, but after turning 70 in September and taking a long vacation this fall, Racanelli said he worked with the board to speed up the timeline.

The aquarium’s board of directors has already begun a national search to find Racanelli’s successor.

Racanelli said he hopes the next chief executive will continue to be a voice for science and conservation, leading up to the aquarium’s 50th anniversary in 2031.

“A really important goal of mine right from the beginning was to move from being a great aquarium that was mostly an attraction and was beginning to dabble in conservation, to a great conservation organization that’s nationally and even internationally renowned that happens to have one of the leading aquariums in the country,” he said. “This next leader can catapult from that point forward and really broaden the aquarium’s impact on the world.”

Maggie McIntosh, a former state delegate who sits on the board of the National Aquarium, said she hopes the next leader will have the “same vision of the aquarium and its place and its prominence in downtown Baltimore.”

“John has always been very, very professional, very much a cheerleader for the aquarium and Baltimore City,” McIntosh said. She had crossed paths with Racanelli often as he lobbied the state legislature for support for the aquarium, she added.

In addition to being a popular destination for tourists and local visitors, the National Aquarium generates $430 million in annual economic impact, according to the nonprofit, and supports more than 3,000 jobs statewide. The aquarium also frequently takes on conservation and cleanup projects in Baltimore and around the state.

Racanelli came to the Baltimore aquarium in 2011, after working at a consulting firm in California that collaborated with institutions such as the International Union for the Conservation of Nature. He was also in leadership positions at an aquarium in Florida and worked as a vice president at the Monterey Bay Aquarium in California, according to his LinkedIn profile.

He started his career as a diver, according to the aquarium, “and has never lost sight of his origins.”

Racanelli’s long tenure at the National Aquarium saw developments including the Blacktip Reef exhibit, which opened in 2013, and the Animal Care and Rescue Center, which opened in 2018.

Last year, the aquarium opened a floating wetlands exhibit in the Inner Harbor, which includes a walkable floating dock that’s open to the public.

Correction: This story was updated to correct amount the National Aquarium says it generates in annual economic impact.