SAN DIEGO (NEW 8) -- The Navy Marine Mammal Program (NMMP) is relocating its bottlenose dolphins out of sight of animal activists.

Approximately 30 dolphin pens have been moved to an area previously used by the Navy off Point Loma near the Space and Naval Warfare Systems Command (SPAWAR) facility.

For the past three years, the Navy has kept its bottlenose dolphins in pens on San Diego Bay near a bridge on North Harbor Drive.

The bridge offered a prime viewing spot for animal activists who, for months, recorded video of the dolphins in the pens.

CBS News 8 aired some of that video in April, showing Navy dolphins in medical pens fitted with flotation devices designed to keep the animals from drowning.

The activists said their video proved the Navy dolphins were in medical distress.

One dolphin had to be euthanized because of complications from old age, the Navy confirmed.

But Navy officials have refused to release necropsy reports detailing the exact causes of dolphin deaths over the past few years.

In a letter to CBS News 8, the Navy claimed the reports were classified and exempt from public release under the Freedom of Information Act.

Back in February, there were more than 70 Navy dolphin pens next to the bridge on North Harbor Drive.  Currently, there are only about 40.

So, why where the dolphin pens moved?

“The dirty secret is that this program is wasteful, unnecessary and abusive,” said David Phillips, the executive director of the International Marine Mammal Project in Berkeley.

“Why are these pens being moved?  Are they being moved because they want to get them away from public view where people can actually film and see what's happening?” asked Phillips.

Chopper 8 video footage confirmed the dolphin pens were relocated south near the Navy’s SPAWAR facility on Naval Base Point Loma, a secure facility that’s not open to the public.

“They’re trying to take this out of public view because they're concerned that what's going to be shown is not going to make the Navy look good,” said Phillips.

The Navy’s SPAWAR spokesperson declined to be interviewed on camera for this report and issued a written statement instead.

“NMMP's current location was always intended to be temporary, and to ensure the safety of our marine mammals during the underwater portion of military construction associated with expansion of the Navy fuel pier at Naval Base Point Loma. It has always been our plan to return NMMP to its original location after that work to the fuel pier was completed. We're now simply moving NMMP back to where it has always been for decades,” the SPAWAR statement said.

The Navy Marine Mammal Program took its website offline in April in the midst of CBS News 8’s investigation.  A cached version of the site can be viewed here.  The site detailed medical research conducted on the Navy’s dolphins.

“As far as the website goes, we've been actively working to improve the look and feel of our entire public facing website for more than a year.  Rest assured, NMMP will be well represented in the next iteration of our websites,” the SPAWAR statement continued. 

Animal activists are calling on the military to shut down the Navy Marine Mammal Program and retire its bottlenose dolphins, which are trained by SPAWAR to detect underwater mines.

“Why is the information about the necropsies, information about the testing and research that they’re doing on these animals, why is it being hidden?” asked Phillips, with the International Marine Mammal Project.

“Instead of taking it out of public view, it's time for people to see what's going on and put some pressure on the Navy to stop this,” Phillips said.