A local resident initially spotted a roughly 42-foot, 25,000-pound fin whale in Potter Pond around 6:30 a.m. Thursday and called the aquarium’s rescue hotline, the organization said in a statement.

Aquarium staffers and veterinarians quickly responded and discovered the massive whale in an “emaciated” and “compromised state,” the release said.

“After a thorough evaluation by Mystic Aquarium’s veterinary team, the whale did not seem to have any apparent or obvious wounds or signs of immediate cause of stranding,” the statement said.

After consulting with personnel from the National Oceanic and Atmospheric Administration, rescuers decided to wait for high tide in the hopes that the whale would refloat and leave the area, officials said.

But there would not be a positive outcome for the animal.

“Unfortunately, the whale did not refloat,” the statement. “With animal welfare as Mystic Aquarium’s top priority and considering the poor condition and low likelihood of survival for the compromised animal, the decision was made to use medical intervention to alleviate the whale’s suffering.”

The statement said aquarium and R.I. Dept of Environmental Management personnel were by the whale’s side when it died around 9:20 p.m.

A necropsy is planned for Friday in an effort to determine the cause of the stranding, the statement said.

“Our hearts go out to this magnificent creature, and we remain committed to the conservation and welfare of all marine life,” said Eric Anderson, the aquarium’s senior director of animal health and welfare, in the statement.

Anderson’s words were echoed by Sarah Callan, animal rescue program manager at the aquarium.

“These cases are always heartbreaking, seeing such a beautiful animal in a compromised state,” Callan said in the statement. “As sad as the outcome is here, I feel some relief that this animal is now at peace. We’ll collect a lot of data today and not only learn more about what happened with this specific whale, but also different threats that this species faces as a whole.”

In addition to the fin whale, the remains of a second whale washed up around noon Thursday on Moonstone Beach in South Kingston, officials said Friday.

“The second whale, a pilot whale, that washed up on Moonstone Beach is decomposed, so most likely was dead for a while and washed in with the most recent storm,” said aquarium spokesperson Meagan Seacor via email.

“There was no stranding in this case. We sent our team out to review and collect data on the animal, but due to the decomposition, we will not be able to conduct a necropsy.”

Travis Andersen can be reached at travis.andersen@globe.com.