Mystic — Mystic Aquarium announced Tuesday that it has received two northern fur seals on a breeding loan from the New York Aquarium.

The brothers, 10-year-old Jack, who weighs 220 pounds, and 9-year-old Sam, who weighs 215 pounds, are now on display in the aquarium's outdoor Pacific Northwest habitat.

This is the first time since 2009 that fur seals have been on display at the aquarium; that's when seals on loan from the Seattle Aquarium and New England Aquarium returned to their home institutions. Mystic Aquarium is one of only four aquariums in the United States to display northern fur seals.

One of nine species of fur seal, the northern fur seal is found the farthest north with many living near the Pribilof Islands off the coast of Alaska.

The aquarium said there is concern about the current status of fur seal populations, especially in the Pribilof Islands, where the population has declined by more than 50 percent since the 1950s.

The aquarium said fur seals are designated as "depleted" under the Marine Mammal Protection Act, meaning the population is below its optimum sustainable population. Factors that may have contributed to past or present declines include entanglement in marine debris, parasites and disease, pollutants and general nutrition.