WESTBROOK – New England’s largest seal rescue and rehabilitation organization is in need of a rescue itself.

The Marine Animal Lifeline has lost a federal grant that accounted for most of its operating budget, leaving it scrambling to find donors before the remaining money runs out.

There is enough cash for several months.

“The bottom line to it is, we need to raise this money fast,” said Greg Jakush, the organization’s founder. “If we’re not successful, we’re not going to be able to continue the rescue and treatment of the animals.”

The nonprofit typically responds to nearly 500 injured and sick animals a year. This summer alone, it has cared for 300 harbor seals.

The National Oceanic and Atmospheric Administration awarded Animal Lifeline $180,000 and $200,000 for each of the past two years but rejected this year’s request for $157,000, Jakush said. The grants covered most of the nonprofit’s $250,000 annual budget.

The Prescott grants were awarded on a competitive basis and the number of applications grew this year, said Teri Frady, NOAA spokeswoman. She said the 95 proposals totaling $8.4 million were more than double the amount of available funds.

“While we can’t fund everyone, we certainly think the competitive process is the way to go,” Frady said from her office in Woods Hole, Mass.

The hit means Animal Lifeline will turn away sick sea mammals from other New England states and from Down East Maine, Jakush said. The organization also will stop investigating reports of seal deaths and carcasses.

Animal Lifeline will have to raise money because there’s little that can be cut. The only paid staff are Jakush, a veterinarian and three veterinary technicians.

Fortunately, Animal Lifeline’s Westbrook facilities are not as busy as they were earlier in the summer.

In July, the organization came close to turning away seals when it reached its capacity of 60, an all-time high. The seals were eating 500 pounds of fish a day and stretching the budget thin, Jakush said.

On Wednesday, four seals will be released into the wild, leaving only 14 in the organization’s care, Jakush said.

“The lucky thing right now is that the season is slowing down. We no longer have 60 animals in for rehab,” he said.

Animal Lifeline, which handles rescues from the New Hampshire border to the state’s midcoast region, is the largest of several facilities that respond to reports of stranded seals and other marine mammals.

Other centers have come to depend on it as a safety valve if they get too busy. The only other facility in Maine that rehabilitates seals is at the University of New England in Biddeford.

The College of the Atlantic, which handles Down East rescues but does not rehabilitate the seals, will have to evaluate its options.

“This is going to affect us greatly in the short term,” said Sean Todd, director of the college’s marine mammal stranding response program.

To the south, the Mystic Aquarium handles rescues and rehabilitation in Connecticut and Rhode Island. In Massachusetts, the Cape Cod Stranding Network and New England Aquarium in Boston handle rescues. In the past, some of those seals ended up in Westbrook.

Jakush had hoped to begin moving his operation to a seven-acre site in Scarborough. The move will save money in the long run, he said.