Jellyfish die-off completes annual cycle

PORT ANGELES, Wash. – With the falling of autumn leaves and return of the chinook salmon comes another seasonal end of the road for another life-form: the jellyfish.

Nearing the end of their lives, open-water jellyfish in the Strait of Juan de Fuca are often washed into bays and inlets by fall and winter currents, sometimes deep into Puget Sound, said Tiffany Pate, naturalist for the Arthur D. Feiro Marine Life Center.

Hundreds of small brown lion’s mane jellyfish were spotted along the Port Angeles waterfront Oct. 9, and on Oct. 15, swarms of sea nettle jellyfish, with yellow bells and red tentacles, were common off Port Angeles City Pier.

To the east, two good places to look for jellyfish are at Fort Flagler and Cape George, where jellyfish often wash ashore at this time of year, said Anne Murphy, executive director of the Port Townsend Marine Science Center.

“They can still sting even after they wash up,” Murphy warned. “Leave them alone.”

The lion’s mane jellyfish can deliver a sting similar to a bee’s – not usually dangerous, but potentially painful.

Other species that can often be seen on the coast, from Sekiu to Port Townsend, include the moon jellyfish and the water jelly, which isn’t a true jellyfish, Pate said.

One that can be quite exciting to find is the sailor-by-the-sea jellyfish, said Murphy.

“I haven’t seen those for years,” she said.

Unlike the previously mentioned species, the sailors-by-the-sea are oceangoing jellyfish that do not live in straits or bays and are often accompanied by other oceanic debris.

If they’re in one bay, they’re probably in the others, she said.

In the open ocean, a lion’s mane jellyfish bell can reach a span of 8 feet, with tentacles 25 to 50 feet long. “The biggest one I’ve seen here was 2 feet across,” Pate said.

Most of the lion’s mane jellyfish seen Oct. 9 were 6 to 10 inches wide.

There isn’t as much food available, so they don’t grow as large, Pate said.

At the end of each summer, most of the area’s jellyfish die, victims of bacterial infection or starvation as their summer plankton food source dies off.

Fish-eating jellies, like the lion’s mane and sea nettle, are usually open-water creatures, and there is less food for them in the bays, Pate said.

When they are pulled into bays and inlets, they become trapped and are at the mercy of the flow of water.

“They’re going to get bashed into rocks, boats and piers,” she said.

Next year, their tiny offspring, which now cling to rocks and pier pilings in shallow waters, will grow to adulthood in early summer and start the process again.