So many grey whales are dying off the US West Coast that scientists and volunteers dealing with the putrid carcasses have an urgent request for coastal residents.

They want to borrow private beaches so the ocean giants can rot in peace.

The number of dead whales washing ashore in Washington state alone, 29 as of this week, means almost every isolated public beach has been used.

Authorities are now scrambling to find remote stretches of sand that are privately owned, with proprietors who do not mind hosting a rotting creature that is bigger than a school bus and has a stench to match its size.

Too Many Dead Whales
Veterinarian Stefanie Worwag, right, participates in a necropsy on a decomposing whale in front of her home (Mario Rivera/AP)

“The preferred option is, at all times, that they just be allowed to decompose naturally,” said John Calambokidis, a research biologist with the Olympia, Washington-based Cascadia Research.

“But it gets harder and harder to find locations where they can rot without creating a problem.

“This is a new wrinkle.”

At least 81 grey whale corpses have washed ashore in California, Oregon, Washington and Alaska since January 1.

If tallies from Mexico and Canada are added, the number of stranded grey whales reaches about 160 and counting, said Michael Milstein, spokesman for NOAA Fisheries.

US scientists last month declared the die-off an “unusual mortality event”, a designation that triggered additional resources to respond to the deaths and launch an investigation.

Too Many Dead Whales
Veterinarian Stefanie Worwag with a whale carcass (Mario RIvera/AP)

The first private-beach owners to respond, a Washington state couple, received their carcass earlier this month.

Volunteers with the so-called “stranding network”, a coalition of non-profit organisations, research institutions and government agencies, attached a rope to the dead whale’s tail and used a motorboat to tow it three miles along the coast to the couple’s beach, where they anchored it to tree stumps.

Mario Rivera and his veterinarian wife, Stefanie Worwag, asked their neighbour’s permission first and are using copious amounts of lime to speed decomposition and reduce the stench.

Too Many Dead Whales
Officials tow a decomposing whale (Betsy Carlson/AP)

They visit the carcass daily and consider it a scientific opportunity.

“It’s decomposing nicely. There’ve been a couple of days this week when I was out there mowing and I was like, ‘Oooph,'” Mr Rivera said of the smell from the 40-foot adult male whale sitting 150 yards from his house.

“But it’s only temporary. It’s only going to be smelling for about a month — and after that, the smell’s gone.”