The seals are back: Delaware's seasonal seal colony is gathering along the coast
Clarification: This story has been updated to clarify that seals are having babies on the Delaware coast.
Spotted some unusually blubbery, flippered vacationers lately?
They're back – that is, harbor and gray seals visiting from New England and Canada.
From mid-February to late April, beachgoers can expect to see seals resting on Delaware sands, marshes and docks, though some seals start trickling in as early as November.
The cold-loving, blubber-covered animals find the Delaware waters hospitable in the winter, but leave once the water warms up in spring. Thousands of other seals choose to overwinter in frigid waters up north.
"It's actually a bit warm for them here, (even in winter)," said Suzanne Thurman, founder and executive director of the nonprofit Marine Education, Research and Rehabilitation Institute, a Delaware stranding response and rehabilitation organization.
At their peak, 50 to 75 seals can be seen together at once, Thurman said.
The seasonal colony is not a new occurrence — it has been building up for years, and there are historic records of seals in the area dating back to the 1800s, Thurman said. Seals were even rendered at the same Lewes fish plant that processed menhaden, which may have reduced their local populations for a time, she said.
What's relatively new is that they are having babies while they're here, she said.
The first seal babies, or pups, believed to have been born on Delaware shores were born in 2014, Thurman said. Observers can tell the age of a seal pup based on whether the animal still has its baby fur.
"The gestation period for gray seals is 11 months," Thurman said. "Although we can't confirm that they are mating in the colony and then giving birth when they return the following year, it seems likely that with that many seals in the same area that mating would occur."
However, as the local population of seals grows, seal predators don't necessarily become more common this time of year.
"Sharks are always out there, as we know from the scavenging they do on our deceased stranded animals," Thurman said. "We also know this from the shark monitoring programs. We are not seeing a huge number of shark bite victims amongst live animals — just on occasion."
As spring turns to summer, the seals will head back north.
In the meantime, seals will often haul themselves out of the water and onto the beach to rest. People should stay at least 150 feet away from any seal, per federal guidelines.
The MERR Institute does not identify the exact location of seal groups in order to prevent curious onlookers from gathering and unintentionally harassing the wildlife, Thurman said.
While some seals may come ashore just to relax, seals in poor health may become stranded.
Anytime a beachgoer comes across a seal on land, they should call the MERR hotline at 302-228-5029, Thurman said. Even though not all seals will need rescuing, the experts at MERR will assess each case to determine which seals need help, she said.
It's a lot of calls, Thurman said, "but that's part of our work."
"We are thankful that people care enough to report these animals to us."
Environmental watchdog reporter Julia Rentsch can be reached at email@example.com.