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Is there a Sargassum Season? Fighting Seaweed in Mexico and the Caribbean

Updated: Mar 24, 2021

*Please read this entire article for context* Seaweed growth in the Caribbean and Atlantic regions may not present itself on beaches and waterside regions of the islands we like to visit until much later in the life-cycle or growth period of the seaweed itself. It takes time for volumes to grow and accumulate, many months of which occurs far out to sea and away from our most beloved vacation destinations.

We do our best to review and disseminate timely information, however this blog article is somewhat static and the presence or absence of any seaweed is impossible to predict. This article should not be construed as advice.

January 2021 Update

The tumultuous year of travel in 2020 might be all the more bitter knowing that it was a relatively calm year for Sargassum. While 2015, 2018, and 2019 remain record years for the seaweed phenomena across the Gulf of Mexico and the Caribbean.

We're also attempting to bring some of your recent experiences to life, whether they be Sargassum successes or seaweed fails > Share your Seaweed Story.

sargassum in the surf in Tulum, Mexico. A pier in the background
Sargassum in the surf in Tulum, Mexico circa 2019

At present there does appear to be some growth across the Atlantic, however it is impossible to predict how much of that growth will increase and by what volume, it may also subside or diminish by some measure even the greatest scientists and equipment are not yet capable of estimating.

What's up with seaweed anyway?

Seaweed is all part of ocean life and features in our day to day lives in ways we don’t often see. Enjoy sushi? It’s an incredible source of iron. Like to golf? Kelp features heavily among the ingredients for commercial fertilizers. Toothpaste? Skin cream? Shampoo??? Yep, some derivative of seaweed is in there somewhere.

Aside from scaring the life out of my wife when a strand touches her foot when we’re at the beach, it doesn’t really bother most of us from day to day. However, in recent memory it seems like a particular variety is making headlines throughout the Caribbean and the Gulf of Mexico.

sushi tray including seaweed wrap
Can't have sushi without seaweed (not sargassum, but you can't have one without the other!)

But before we get carried away with the solution…

What is Sargassum seaweed?

The Sargassum is a brown macroalgae, meaning it is a bit larger than the tiny floating particles or green slime we might associate with a poorly maintained aquarium. It’s an important part of the ocean ecosystem and its floating tendrils offer not only a great source of food for certain creatures, but a refuge for small sea-faring beasts.

It is suggested that even small sea turtles find it a safe place to hang out and to find food as they grow. I’ve seen some claims that over 100 species of fish and other marine life are regularly found in floating fronds of sargassum. Sounds fun so far, no?

Is seaweed really a problem in Mexico and in other parts of the Caribbean?

It is a naturally occurring phenomena, and like all things floating on the sea it can wind up on the beach when winds, tides, and currents are involved. A bay or marina, maybe the cove of a secluded beach – all excellent traps for floating debris, including sargassum!

The issue itself isn’t so much that there is seaweed washing up on beautiful white sand beaches around the Gulf and the Eastern Caribbean, it’s those peak weeks when the volume which arrives is immense or the day to day arrival of more seaweed seems unending.

Some beaches and destinations claiming they’ve experienced 4m (13 feet+) or more, up to 10m (I can't fathom this depth on / near a beach. At 32 feet, it seems unreal!) depth of washed up seaweed during several weeks of the most intensely affected years.

sea turtle returning to the sea over sargassum, having nested on the beach
How much sargassum is too much for a turtle?

Is the seaweed harmful?

You could argue that the beaches covered in seaweed are an issue beyond being unsightly or carrying a bad smell as the material decomposes (it’s in fertilizer, remember?). That sea life such as nesting or hatching turtles are affected, for example. While its removal may also contribute to disturbing turtle nesting and hatching, it may intensify beach erosion and other concerns.

More significantly, it traps human garbage which can be not only unsightly but also a health issue in its own right. It is also suspected to transport invasive species alongside the endemic ones, such as the current scourge of the Caribbean – the lion fish.

Lionfish swimming in a reef
The double-edged sword, sargassum may help invasive predators such as the Pacific lionfish continue to spread throughout the Caribbean, where they disrupt local wildlife populations

As the materials decompose, again remembering it’s used in fertilizer, it can encourage blooms of microbes which do present a complication for both health and comfort – itchy!

Some reports from August of 2018 suggested that 120,000 cubic meters (more than 42,000 tons) of detritus had been removed from beaches of the Caribbean over the preceding 90 days. That is an enormous amount of anything and managing the recovery and disposal of material is surely a monumental effort.

Which resort areas may be affected by the seaweed?

Although it might be most prevalent in the news, owing to its popularity as a destination. Mexico is not the only region affected. Much of the Sargassum growth initiates in the Atlantic, north of Brazil. But as it starts to peak and bloom or break up, it shifts with weather and currents. It can start to float westward and can end up on pretty much any spot with a beach, adding to any quantities already present.

Mexico's Quintana Roo, a popular strip for visitors which might best be known for its world-famous resort areas such as Cancun and Playa del Carmen, the Riviera Maya - but also for up and coming destinations such as Tulum and destination wedding hot spot, Cozumel.

Reports in years past have highlighted just how far the seaweed can be distributed, with sites ranging from Barbados to Guadalupe, Puerto Rico to Trinidad, or even Belize through to South Florida. It's hard to pinpoint the most active spots, just as predicting the weather several months in advance may be.

destination wedding set up on a beach in Mexico

How Mexico and other destinations in the Caribbean are solving the seaweed problem?

Previous efforts included on-site removal either by hand or with heavy machinery, with plenty of new ideas and aspirations more akin to prevention. The theory being that it is easier to prevent landfall and less so to prevent or limit any actual growth.

Sargassum on the beach in Belize
Sargassum on the beach in Belize

Mexico calls in the Navy to deal with seaweed

Reports during the peak of 2019's season came from Mexico News Daily and suggested that the Mexican Navy is the most well-equipped to handle the prevention and clean-up efforts.

The whole of Mexico recognizes the reliance on tourism to their growing economy and despite having re-apportioned their budget for Visit Mexico centers to a huge new highways project, the government does not want the issue to reduce the good time visitors have enjoyed for decades on the beautiful beaches of the Yucatan.

The Mexican Navy not only has the budget-access and equipment, those locals in Service have knowledge of the waters and coastal zones affected which far exceeds that of any commercial operation since considered. The situation in 2018 being more intense than that of 2015, well, it’s really brought the issue to light as one which needs a fair bit more attention.

You might be left wondering, is there a season or time of year during which the seaweed is better or worse?

turquoise water and white sand with palm trees in Cozumel, Mexico
Clear water and white sand with palm trees on the beach in Cozumel, Mexico

What is the official Sargassum Season?

Based on scattered reports from clients and colleagues, alongside some research into online reviews, and a small but growing set of climate and oceanographic resources, it seems as though the season starts depositing increased algae from about the end of February and may continue until mid-late August.

Following rather noticeable increases during brief periods of 2015, 2018, and 2019, the University of South Florida has teamed up with NASA under the Optical Oceanography Laboratory and the College of Marine Science to help deliver more visual reporting to help understand and attempt to predict seaweed volumes and movements (original reports).

Growth is predicted in part by the presence and estimated size of early blooms throughout the Caribbean and Atlantic regions as early as December and January, however much of the growth doesn't arrive or make land fall until April or later. The bloom's after effects may be seen as late as August, but should have already started to reside by the end of June.

Conveniently, it is most intense when people aren't visiting the region as much. May through August coincides with warm seas which bring the prospect of hurricane weather to the Caribbean and the Gulf of Mexico. School children may have the most time off, but families tend to enjoy the warmer weather enjoyed at home during these months.

White sand beach and beautiful resorts of Cancun, Mexico
White sand beach and beautiful resorts of Cancun, Mexico

Does that mean my family vacation will be safe from seaweed in January? Will we be affected in July?

Without sounding like I’m avoiding a direct answer, it’s too difficult to say a definitive "yes" or a definitive "no".

As described above, the seasonality tends to be more intense toward the low season for the Caribbean and Mexico. If you're planning a beach holiday or a cruise during this time, seasonal considerations should be included in any discussion.

An unfortunate reality all around the world is that the biosphere is in change, the balance of weather events has been altered and life will try its hardest to account for any change and strive for long term balance.

That means seaweed growth may be a new reality for holiday seasons and which means local businesses, including destination resorts, and governments will have their own new seasonal tasks – much like anyone living in the north experiences snow removal during the winter. Life just goes on.

lanterns in the sea breeze at night in Tulum, Mexico
Beach nights in Tulum, Mexico. Sargassum isn't going to bother you here!

Is it possible to accurately predict the Sargassum Season?

Some of the most capable individuals and institutions are tackling this very issue, trying their best to understand the effects of the moon on algae growth, hydrodynamic models of the changing ocean currents on dispersion, and more.

And bearing in mind that, like any season or other natural phenomena, the long term trends are available but specific predictions are not. We might expect winter to become spring each year in March or thereabouts, but we're left with a groundhog to indicate the specific advice for each year's arrival of warmer weather.

Just looking at my phone's weather app two or more times in the day can result in two or more distinct weather predictions for the current weather!?!

Feel free to return to this article or reference it in planning your own trip, but don't be afraid to search our community or contact one of our experts directly to discuss your vision for a vacation and how it might best be achieved while worrying less about Sargassum.


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On the forum I posted I posted that its expected to be a heavy sargassum season for 2022 in the Caribbean and Gulf of Mexico. I am at Miami Beach right now and there is a lot of sargassum that should give you an idea of what to expect further south.

Plan B - Europe, Asia or elsewhere 😉


Unknown member
Feb 24, 2020

Probably the best synopsis of Sargassum I've read. Thanks for sharing. I've been traveling to the Caribbean for many years and just like the tides, Sargassum ebbs and flows (pun intended). But it is harmless (except for some foul smells) and is unpredictable. But don't let it be a deterrent for traveling south. The resorts all do a great job cleaning up any debris or Sargassum each morning.

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