After five years of weighing options on how to best provide for its pod of Atlantic bottlenose dolphins, the National Aquarium of Baltimore announced this morning that it will build a first-of-its-kind ocean sanctuary for the marine mammals.

National Aquarium CEO John Racanelli said in a statement that the decision is a natural progression of understanding how best to care for captive marine life.

"Although this decision is about our group of dolphins, it is every bit as much about our humanity; for the way a society treats the animals with whom it shares this planet speaks volumes about us," he said.

Officials are currently exploring sites in Florida and the Caribbean for the sanctuary, adding that they hope to receive donations to make the project a reality by the end of 2020.

"There's no model anywhere, that we're aware of, for this," Racanelli told the Associated Press. "We're pioneering here, and we know it's neither the easiest nor the cheapest option."

Initial criteria for the sanctuary include a tropical or sub-tropical environment, natural stimuli (such as native plants and fish), and customized care options for each dolphin. The aquarium also wants the site to "serve as a center for applied science that advances knowledge and conservation."

Animal advocacy groups rushed to praise the news. "The National Aquarium's welcome move recognizes that the needs of intelligent, sensitive, far-ranging dolphins simply can't be met in captivity," wrote PETA Executive Vice President Tracy Reiman. "This spells the beginning of the end for dolphin captivity and the start of an age in which SeaWorld, the Miami Seaquarium, and other marine parks reject excuses not to retire long-suffering captive dolphins including orcas to sanctuaries."

The National Aquarium's decision comes on the heels of last month's announcement of "The Whale Sanctuary Project," a new nonprofit aimed at creating the world's first seaside sanctuary for whales and dolphins. The estimated $20 million sanctuary will be located in a cold water site in North America and cater to orcas, belugas and dolphins retired from entertainment facilities, as well as injured or ill animals rescued from the ocean.

Like the National Aquarium, the Whale Sanctuary Project hopes to have its site up and running within three to five years.