SWAMPSCOTT — Two harbor porpoises were found washed up on King's Beach yesterday morning about a quarter-mile apart, according to a spokesman for the New England Aquarium.
The sight of the marine mammals dead on the beach drew curious stares and cellphone photos from walkers, some of whom wondered just what had come ashore.
"It's sad," Michelle Lucier of Lynn said. "Something got a hold of him."
The first animal spotted on the beach was reported to police just after 9 a.m. near a culvert where Lynn Shore Drive and Humphrey and Ocean streets converge.
Later, a dog walker told a field volunteer from the New England Aquarium there was another porpoise on the beach near Wallace Road in Lynn.
Both of the beached animals looked to be about 4 feet long. They had dark gray bodies and white undersides.
The porpoise found in Lynn appeared to have part of its jaw ripped off and a foot-long gash in its underside. It also had claw marks on its carcass.
"These are wash-ups of harbor porpoises," said Tony LaCasse, the aquarium's media relations director. This was not a stranding. Harbor porpoises are the smallest members of the dolphin family, LaCasse said. They grow to be about 41/2 feet long.
It appeared the badly decomposed porpoise in Lynn was an adolescent female that had been dead for three to seven days.
"It had a lot of damage already done by gulls," LaCasse said.
The porpoise in Swampscott was also badly decomposed. When an animal is found in such bad shape, it is not taken in for a necropsy because such a procedure would not yield much information about how it died, LaCasse said.
Field volunteer Diane Treadwell of Marblehead and her friend Karla Kelley, also of Marblehead, went to the beach on behalf of the aquarium.
"I'm collecting some measurements and data," Treadwell said as she measured the first porpoise. She did not have any information about how the porpoises may have come ashore, as her role was to relay information back to aquarium biologists.
"We have lived here many years, but we've never seen anything like this wash up before," Linda Caruso of Swampscott said. "As sad as this is, this is one of the beautiful things about living on the ocean. It's something new every day."
As Treadwell measured the first dolphin, Benoit Denizet-Lewis of Lynn, who walks his dog, Casey, on the beach twice a day, came by and said he found a similar animal on the beach, in the direction of Red Rock Park. Treadwell and Kelley went off to study that carcass, but before they did so, Treadwell used a red marker to mark the first porpoise with the date so if it washes up somewhere else, it will be clear it has already been studied.
Turns out, harbor porpoises are a common sight in the waters off Massachusetts.
"Whether it's Salem Harbor or the harbor around Lynn, there are harbor porpoise in there all winter," LaCasse said.
In the summer, harbor porpoises migrate to the northern part of the Gulf of Maine, where the water is cooler, but they are a common sight in late winter and spring on the North Shore. Often, juvenile and adolescent animals will go into harbors and up rivers and estuaries chasing schooling fish that are spawning.
"There is usually a fair amount of mortality in this group," LaCasse said. The aquarium fielded a spate of reports of harbor porpoise carcasses in midwinter, with seven found in six days from Plymouth to Cape Ann.
LaCasse said people should call the aquarium's stranding hotline, 617-973-5247, if they spot carcasses of harbor porpoises or simply see seals sunning themselves on the beach.
"It provides us some valuable information," LaCasse said.
Staff writer Ethan Forman can be reached at 978-338-2673, by email at firstname.lastname@example.org or on Twitter @DanverSalemNews.