HALIFAX -- An undisclosed spot somewhere off Nova Scotia has been shortlisted as a potential site for the world's first seaside sanctuary for whales and dolphins born in captivity.

The pioneering effort started two years ago when the U.S.-based Whale Sanctuary Project announced it was looking at 100 possible sites across North America.

Lori Marino, president of the non-profit group, confirmed this week that the list has been narrowed to two locations: Nova Scotia and Washington state -- with a couple sites in British Columbia as backup choices.

She says public attitudes have changed toward whales and dolphins being forced to perform at marine parks and aquariums.

Renowned marine biologist Hal Whitehead, a professor at Dalhousie University in Halifax who specializes in the study of whales, says he supports the project.

Marino says her group plans to make a decision before the end of the year, and the goal is to have the large sanctuary operating by 2020.