Washed up Sailors at Beach Create Stink

By Ryder W. Miller

Creating a stink and a curiosity in early April, huge numbers of By-the-Wind Sailors, floating marine polyp hydroids, washed ashore over the entire length of Ocean Beach, as well as beaches to the north and south.

"Don't stand downwind," warned Mary Jane Schramm, program assistant at the Gulf of the Farallones Marine Sanctuary.

Through mid-April, the stench could be noticed beyond 47th Avenue; huge numbers of By-the-Wind Sailor corpses and other dead marine animals can still be found on the beach. 

San Francisco State University Marine Science professor Thomas M. Niesen writes in the  Beachcomber's Guide to California Marine Life that the By-the-Wind Sailors (Velella velella) are cnidarians floating polyps. They have stiff exoskeletons made of chitin, a gas-filled float, and a transparent sail.

The "sail" is mounted vertically on the long axis of the body, which can grow three inches long. They live on the ocean surface and their mouths are on their underside. 

When the coastal wind shifts westerly or southerly, the animals are driven onshore.

Niesen explained that they are not technically jellyfish but of the class Hydrozoa, rather than the true jellyfish from the class Scyphozoa.

Velella velella release "babies," which grow on the ocean's surface in floating colonies. In the wild, Velella velella predators include sun fish and the blue sea slug.

"These animals create quite a stink for a short time, but quickly decompose, leaving behind only the thin, blue, cellulose-like chitinous exoskeletons which can persist on the beach for months," Niesen notes. 

"This is a little over normal, but it is not extraordinary," said Niesen of the washed-ashore carcasses.

He relayed an old sailor's tale: "A lot of By-The-Wind Sailors means it will be more windy and a better season."

The large number of By-The-Wind Sailors washing ashore suggests that nearby ocean water is nutrient rich and productive. Some positive signs have also been observed at the nearby Gulf of the Farallones Marine Sanctuary. Schramm said birds were breeding early at the Farallon Islands and Humpback Whales have been seen in the area.

Bill Sydeman, director of marine studies at the Point Reyes Bird Observatory, was not concerned that the washed up "sailors" will bother bird life.

"I don't think so," Sydeman said, adding there are no birds that really eat them. "I don't think they are toxic," he said.

KTVU Channel 2 News reported April 13 that, like their  cousins the jellyfish, Velella velella do have active stinging cells while they are alive.

Of more concern are the true jellyfish that wash up on the shore at Ocean Beach. It is not advisable to touch them. 

"It's an interesting phenomenon," said Sydeman of the By-The-Wind Sailors. "It's neat in a way, if you don't mind walking on them."