A Gelatinous Invasion

Our beaches are teeming with tiny gooey blobs. Though they look like jellyfish, they’re called salps. Here are the basics on this remarkable invasion.

Salp © Cindy Bortee

Salp © Cindy Bortee

About Salps

Salps are stingless, barrel-shaped creatures that travel by jet propulsion, squeezing water through their bodies. During different parts of their life cycle they may live individually or in chain-like colonies.

Don’t be deceived by our beach visitors’ almost featureless appearance—when salps are young, they have a rudimentary “spine” called a notochord. This puts them in the same scientific phylum as vertebrate animals like us.

Salps on the beach © Cindy Bortee

Salps on the beach © Cindy Bortee

Efficient Ocean Filters

As they jet along, salps filter the water for ocean microorganisms called phytoplankton, which become their food. Scientists have found that they’re adept at extracting even the tiniest organisms from the water.

What salps don’t use, they pack into dense, carbon-rich pellets of poop that sink to the seafloor. Because they remove carbon from the surface waters, they help to reduce the amount of carbon dioxide in the atmosphere—and combat climate change.

Booming Blobs

A number of factors can lead to a population explosion of salps. One is a boom in phytoplankton. When this prey is depleted, salp numbers will also decline. Another factor: ocean currents and winds that bring the salps to shore. While it lasts, this phenomenon may bring an unexpected benefit: bizarre-looking ocean sunfish, which are popular with whale-watchers, have been common in the waters off Massachusetts. These giants often eat gelatinous creatures such as jellyfish and salps.

Ocean sunfish © Chris Leahy / Mass Audubon

Ocean sunfish © Chris Leahy / Mass Audubon

Have you experienced this phenomenon? Let us know in the comments!

16 thoughts on “A Gelatinous Invasion

  1. Esther

    I found slaps at Long Beach in Plymouth, Ma today, they were very shiny in the sun, very interesting, I thought they were baby jelly fish.

    Reply
  2. ruth housman

    reassuring. I thought they are jellies and that a problem with my foot, an allergy comnected to food might also have been exarcebated at Humarock beach!

    Reply
  3. Kathy

    We kayaked both Saturday and Sunday (9/19, 9/20) off theDriftway in Scituate out to the Spit and North River and there were literally millions/billions of colonies of salps in the water! Like little jelly worms, some long in double chains, but more in single “gelatinous blobs” filling the water and gathering on our oars and in the sand as the tide ebbed. Incredible–have never seen their population this explosive in the river and estuaries around the coastline here these past few years.

    Reply
  4. joan zofnass

    Last week have seen these salps on the beach of Marblehead MA as well as in the ocean while paddle boarding. Some look like a string of these salps and others are singular. Preston Beach is covered with millions of them and when swimming I could see and feel them. I’m wondering what the blue is in them and also why the gulls aren’t eating them.

    Reply
  5. Kurt

    We saw two ocean sunfish on our BHC whale watch out to Stellwagen Bank. I don’t think a lot of the other whale watchers were as impressed as I was.

    Reply
  6. Lisa Hoguet

    Very cool! These were all over the beach in Marblehead this weekend and the kids were trying to figure out what they were.

    Reply

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