This deceased seal pup was found on a Maine beach by Marine Mammals of Maine. Credit: Courtesy of Marine Mammals of Ma

Even as volunteers for Marine Mammals of Maine responded to more dead seals in southern Maine on Monday — more than 125 since Aug. 12 — officials from various agencies were clear that no cause for the “die off” has been determined.

“There have been no results yet to say what’s going on,” Lynda Doughty of the Harpswell-based nonprofit organization said Monday. “Other media speculation is that pollution is causing the die-off [but] no conclusive tests have been returned on southern Maine seals.”

Friends of Casco Bay, a marine stewardship organization founded in 1989 to improve and protect the environmental health of Casco Bay, reported Monday that tests conducted last week “show good water quality with enough oxygen for marine life.”

On Thursday, NOAA Fisheries New England/Mid-Atlantic wrote on its Facebook page that while samples have been taken from the seals and are being tested, “we don’t have any results yet — and that may take a few weeks.”

Previous mass deaths of seals in Maine have been attributed to avian influenza, distemper and harmful algal blooms such as red tide, the organization said.

On Monday, Doughty said the number of mostly seals found dead or stranded in southern Maine was “out of the norm for what we normally see.”

But so little is still known about the cause of the recent spate of deaths that National Oceanic and Atmospheric Administration has not deemed it an “unusual mortality,” Doughty said, and she has not yet been able to apply for emergency federal funding.

“There’s obviously something going on, but because we don’t know what, they’re not calling it that,” she said of the designation.

Doughty said that despite previous reports, the nearly $50,000 John H. Prescott Grant recently awarded to Marine Mammals of Maine was for “basic operational support,” and not specifically earmarked for the organization’s response to the current die-off of seals in southern Maine.

In fact, she said her organization applied last year for a $100,000 grant, and was recently notified it would receive $49,669.

Volunteers and staff continued on Monday to retrieve dead seals from beaches in southern Maine, perform necropsies and send samples to labs approved by NOAA, which is paying for the testing, Doughty said.

But the Marine Mammals of Maine staff and volunteers continue their efforts — now greatly increased, having responded to more than 150 animals in the past eight days — with the same funding it’s always had.

On Saturday, the team had to euthanize a young harbor seal even as it continued necropsies on those found dead in an effort to determine exactly what is causing the deaths.

“I can’t say enough about how our volunteers have been out in the field — really dedicated and trying to respond to every report coming in, and our staff has been trying to get samples and get the animals necropsied,” she said. “I know some people are frustrated and think it should happen sooner, but it could take maybe until the end of this week or early next week before we might know something.”

Doughty asks that anyone who sees a stranded or dead seal in Maine to call (800) 532-9551.

Follow the Bangor Daily News on Facebook for the latest Maine news.