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Sargassum Seaweed: Is It Affecting St. John?

Sargassum seaweed often affects Haulover north. This picture was taken late last year.

People have been emailing me quite a bit lately asking about seaweed and whether or not it’s affecting St. John. It sounds like the stateside media keeps chatting about a 5,000-mile seaweed belt that is apparently heading toward Florida. Today I am going to tell you all about sargassum – this particular type of seaweed – and how it is currently affecting St. John.

Sargassum is nothing new to the US Virgin Islands. The first time I recall really seeing it affect the island was back in 2014 when it covered Cruz Bay beach. Since then, it has come and gone. You may have noticed it when flying if you like to look outside the airplane window. It almost looks like an oil slick from above.

So what exactly is sargassum? Sargassum is a type of algae that floats in island-like masses and never attaches to the ocean floor, according to the National Oceanic and Atmospheric Administration. This floating habitat can provide food, refuge, and breeding grounds for a variety of animals such as fish, sea turtles, marine birds, crabs, shrimp and more. Sargassum serves as a primary nursery area for a variety of commercially important fish such as mahi mahi, jacks and amberjacks.

Sargassum up close

There are a few downsides of sargassum, however. First, when it really pools on a beach, it is very difficult to swim through it. That means whichever beach it affects is somewhat closed off to swimming, etc. Also, when it dries on the beach and starts to decompose, it can be very stinky. It emits a smell that is similar to rotten eggs.

The good news? It’s really not affecting St. John at the moment. The better news: It rarely affects our North Shore beaches.

The winds here typically go from east to west. (That’s from Coral Bay to Cruz Bay.) This means that the sargassum, when we have a lot in the area, floats past our more popular beaches. I see it affect Jumbie the most, as that beach faces a more northeasterly direction. But at the moment, there is a only a tiny bit of dried, and not stinky, sargassum on that beach.

The winds typically go east to west here on St. John.

St. Thomas, unfortunately, is a different story. The beaches at Margaritaville, Sapphire and the Ritz, for example, all face east. This means that sargassum often affects those resorts. The good news there is that the staff removes it regularly, so it will not affect your vacation if you are staying over there.

So as you know, I see a great deal of the island nearly every day for my Explore STJ island tours. This is what I have seen with regard to Sargassum on some of the more popular beaches:

  • Cruz Bay: Very rarely, although we did have a strange westerly wind recently that brought some in. That is gone now.
  • Hawksnest: We get a little bit from time to time, but it is never enough to really affect the beach.
  • Jumbie: This is the beach where I see it the most. It has had so much at times that the beach has been un-swimmable. There is a small amount of dried sargassum on the beach now, but not enough to affect it.
  • Trunk Bay: We get a little bit from time to time, but it is never enough to really affect the beach.
  • Cinnamon: Honestly, I cannot recall seeing much here over the years, but I am not 100% certain about this one. So sorry all!
  • Maho & Francis: Extremely rare
  • Haulover: I rarely see it on Haulover south. I often see it at Haulover north.
  • Hansen & Saltwell Bottom: I rarely see it here. There was a small amount last week, but that has been cleaned up, and it’s gone now.
It is practically a sargassum-free week here on St. John. Picture taken on Monday.

So there you have it. Sargassum is nothing to cancel a vacation over. If things change and become more problematic, I will absolutely let you all know.

In the meantime, start looking to book your next St. John vacation. The island is quieter than normal right now, so there are deals to be had.

Looking to take a St. John island tour?

Learn more here –> Full & half days available. Rated “Excellent” on TripAdvisor.

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Tag: St. John sargassum seaweed

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  1. Marilyn Siebenmorgen

    It does cause respiratory issues. We are in Barbados and it is terrible here on Atlantic side. I’m suffering from the smell and air. Unfortunately this resort doesn’t clean beach, they close it and bus people to other side. 🤦‍♀️

  2. Mike D

    Hawksnest had several huge waves of it (different ages) on the Caneel side when I swam over there from main Hawksnest in July 2021. Like one at the surface, and older sargassum near the bottom.

  3. Pingback:New Sargassum Weekly Updates - Explore STJ

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