Sargassum Seaweed – What You Need To Know

Recently the amount of Sargassum Seaweed arriving on beaches full of vacationers increased. But what’s the situation now? Are there still lots of sargassum seaweed? Where does it come from, what is it, and what’s being done about it? Also, how does it affect marine life? And which beaches have the worst Sargassum seaweed and which are the best? Read on and find out.

What Is Sargassum Seaweed?

Sargassum seaweed is brown and was named by Portuguese sailors on a Christopher Columbus voyage across the Atlantic. The sailors were passing across the Sargasso Sea at the time.

Uniquely the Sargassum seaweed consists of brown algae and small ‘air bladders’ that keep the seaweed afloat. Growing to a length of several meters it is present throughout tropical areas of the world. It is the only seaweed that doesn’t begin life attached to the ocean floor. Instead, the ocean currents and wind push it around. While its edges lock together like Velcro to form large mats, it gets pulled apart in windy storms.

The large mats of Sargassum seaweed drift along propelled by wind and ocean currents. These mats provide shelter to over 100 marine species as well as a home to those that live within the seaweed. For instance, the sargassum fish has developed camouflage to hide from predators. As well, young sea turtles use the Sargassum seaweed for shelter and food. Until they are large enough to survive elsewhere. Other species dependent on the seaweed include crabs, shrimp, squid, snails, eels, and fish including Mahi-Mahi.

Why Does The Amount of Sargassum Seaweed Change?

Sargassum seaweed grows and declines based on seasonal changes in water temperature. Only a few years ago there were concerns about declining Sargassum. At that time restrictions limited the amount harvested for animal feed and fertilizer.

Since 2011 increasing amounts have arrived along the shores of Caribbean countries. Currently, it affects twenty-two Caribbean nations. These include Mexico, Dominican Republic, Barbados, Grand Cayman, Jamaica, Haiti, Puerto Rico, Saint Martin, Antigua, Guadeloupe, Belize, Bermuda, Martinique, St. Lucia, British Virgin Islands, and Trinidad & Tobago. For example, in 2018 more than 1,000 square miles of Sargassum seaweed arrived in the Caribbean. That was 3 times the amount in 2015. And 2019 produced a record year for Sargassum Seaweed. Beating the record set the previous year.

But what is causing these increases? According to scientists, the growth of Sargassum seaweed changes with the number of nutrients. As well as with the ocean temperature. So, the rise in seawater temperature is a factor. Secondly, there is an increase in the number of nutrients from the Amazon River and fertilizer run-off. These both contributed to large algae blooms stretching from Brazil to West Africa in 2015, 2018, and 2019.

As well, changes in ocean currents are also why more seaweed is hitting some coastlines. For example, ocean currents have diverted seaweed from the Sargasso Sea (near Bermuda) towards other areas in the Caribbean.

Sargassum Seaweed in 2020

The amount of Sargassum seaweed in 2020 declined from its peak year in 2019. There has been an 80 percent reduction in the amount of Sargassum seaweed in 2020 compared to 2019. For example beaches along the coast of the Riviera Maya, in Mexico are free of Sargassum seaweed. And are expected to remain so for the coming months. Not only was the amount of Sargassum seaweed much reduced but municipalities were also very prepared. Many communities have made Sargassum collection vessels, seaweed barriers, and extra cleaning equipment.

Impacts of Sargassum Seaweed on Marine Life

While there are impacts on tourism from an increase in seaweed, it poses little to no health risk to humans. But the Sargassum seaweed, if left to accumulate, can form large banks making access to the ocean less pleasurable. Also, if left it will begin to compost and decompose. All making it less desirable for tourists and beach vacation goers.

But, what is the impact on marine life? If the Sargassum seaweed provides habitat and protection for some species isn’t it a good thing? That may be the case when it is out in the middle of the ocean, but when it hits the shoreline it can create other problems.

Accumulation of Sargassum on beaches impedes turtles from accessing nesting sites. As well, baby turtle deaths have been reported from hatchlings being unable to get to open water. Also, as the Sargassum decays it consumes oxygen, which can impact marine life in coastal areas. Coral reefs, juvenile fish, some shellfish species, and seagrass could all be affected. But this year in Akumal, in the Mayan Riviera there were record numbers of turtle nests and a significant increase over 2018 and 2019. 

What Is Being Done to Combat Sargassum Seaweed

In Mexico, in 2015 authorities established guidelines for the collection of Sargassum seaweed on the beach. These guidelines protect the beaches and creatures living or nesting on the beaches.

While the seaweed only takes 8-16 days to decompose, several jurisdictions, have acted. Removal of the seaweed from beaches is a major activity now. For example, hotel operators use workers to remove the seaweed from their beaches. And, in 2019 hotels offered shuttle buses to beaches that were less affected by the Sargassum seaweed. Also, in Barbados equipment to load sugar cane now picks Sargassum off the beaches. While in Guadeloupe a new boat collects the seaweed using a conveyor belt.

Similarly, the Mexican Government is hiring personal to collect and remove seaweed. Between the federal and municipal governments, a budget of over $11M USD funded initiatives to combat the problem. This included building six sargassum vessels and the purchase of 4,252 meters of containment barriers. As well as four beach sweepers and tractors. The funds also support the following activities

1) Detection - real-time observation to know the seaweed location to make decisions on the collection before arriving at the coast.

2) Containment - The Mexican Navy is collecting seaweed at sea using ships, barges, and barriers. By June 2020 the Navy reported the removal of 5,700 tonnes of Sargassum seaweed out in the ocean. As well Navy marines have installed 4,252 meters of floating barriers at sea to stop the seaweed from washing up on beaches along the coast.

3) Collection - Setting up teams to clean, transport, and dispose of the Sargassum from the beaches. In Cancun alone, in the first 6 months of the year, 9,132 tons of seaweed were collected from the beaches in Cancun.

4) Monitoring – Monitoring is being undertaken of the coastal water quality and air. Sargassum seaweed monitoring networks are set up along the coast. And satellite tracking is also being used.

Sargassum Seaweed Uses

As many thousands of tonnes of the Sargassum seaweed is being collected, novel uses are being found for it.

Sargassum Seaweed Used as a Plant Tonic, Biofuel, or a Mulch

In St. Lucia one company is creating a plant tonic out of it. In Tortola, potential uses are as a biofuel, and in landfills, and as a mulch for crops. While there is also the potential for medical and pharmaceutical uses. Knowing its healthy properties, the Chinese have used Sargassum seaweed as a medicine since the 8th century.

Sargassum Seaweed Used to Build Sand Dunes and as a Fertilizer

Sargassum seaweed uses include to help build up sand dunes, to combat the threat of erosion from storm surges. And, in Barbados, they are starting to use Sargassum to produce fertilizer.

Sargassum Seaweed Used to Make Bricks

Sargassum has recently been used in the preparation of blocks or bricks for construction. This application is ecologically friendly and economically profitable. The construction of approximately 40 square meters, uses 20 tons of Sargassum seaweed to make 2,150 blocks of the seaweed. For example, a new Government facility in Puerto Morelos was built using bricks made from Sargassum seaweed.

Eating and Drinking Sargassum Seaweed

Other uses for the seaweed could be in Asian inspired recipes. For example, stir-fried and then simmered in water and soy sauce with vegetables makes a healthy meal!

And there are now even cocktails made using Sargassum seaweed! The exotic cocktail opposite is made with tequila, aquafaba, lemon juice, lavender biter. Added to this are dehydrated portions of pineapple and Sargassum seaweed. But, the process starts much earlier. The Sargassum seaweed is mixed with pineapple, honey, rosemary, and star anise after it is collected from the ocean and rinsed.

Beaches That Are Mostly Seaweed Free

Finding beaches that are likely seaweed free during a time when seaweed is plentiful isn’t as daunting as it may seem. First of all, find those beaches sheltered from the ocean currents and wind. While that’s helpful, as ocean currents and winds change so can where the seaweed lands. So local knowledge is required (see a list of beaches below).

While some beaches often receive more seaweed than others it also depends on how it is managed. Because of the work to remove the seaweed, a beach that receives a lot of seaweed can have less seaweed than others that don't manage it as well. For instance, some maps show a large amount of seaweed hitting certain beaches. But these can be misleading. Parts of the beach may have seaweed, but specific sections that are more sheltered and/or better maintained can be devoid of it.

So, when looking for a beach to visit during a high growth seaweed year, such as in 2019, it’s best to have local knowledge. For example, the coastline south of Playa Del Carmen and past Akumal can sometimes be reported with high levels of seaweed. Yet, beaches such as Akumal Bay and Xpu-Ha (opposite) often have much less seaweed. This is in part due to coordinated efforts to remove it regularly. Also, Akumal Bay has sections even in extreme times, where there is little seaweed. This is in part because of the curvature of the bay and the reef. 

Similarly, South Akumal, such as the beach at Aventuras Akumal, often receives less seaweed than other beaches. Yet, Xcacel a little further south has lots of accumulated seaweed because it is not removed as frequently as in other areas.

In 2019 beaches south of Tulum received a lot of Sargassum seaweed. Less so this year. But in a year of high seaweed levels, you should check with the specific beach. If you contact the local beaches and beach clubs, they will often send you a picture of the beach so you can see the conditions that day. Or, you can visit the Sargassum Early Advisory System. By searching their system, you can look at forecasts for predicted amounts of Sargassum throughout the Caribbean. 

Beaches Usually With Lower Levels of Sargassum Seaweed

Usually Low Levels of SeaweedUsually Moderate Levels of SeaweedLikely Having Abundant Seaweed
MamitasPlaya Delfines, CancunPuerto Morelos
PaamulPuerto Esmerelda, Playa Del CarmenXcacel
Xpu-HaSoliman BayBeaches south of Tulum
Akumal BayTankah Bay
Akumal Bay South/Akumal AventurasPlaya Paraiso, Tulum
Playacar, Playa Del Carmen

More information on each of these beaches and their locations can be found here.

What Do You Do If Your Beach Has Sargassum Seaweed

The Sargassum conditions can change from one day to the next. So often it’s a case of waiting for a day or 2 till the seaweed has cleared, or finding another less affected beach. However, unlike some other Caribbean destinations, the Riviera Maya has many activities that you can do, besides going to the beach. It was one reason why the Riviera Maya was recently voted the best vacation destination in Mexico. So perhaps its time to try one of these for a couple of days.

Mayan Ruins

The Riviera Maya has an extension number of interesting Mayan archeological sites. They range from smaller off the beaten path ruins to large and impressive sites. Read our review of Mayan Ruins in Mexico or Chichen Itza - The Ultimate Visitors Guide to find out more.


Cenotes are natural sinkholes created where a cave ceiling has collapsed and left natural swimming pools. These caves were the only source of water in the jungle for the Mayan civilization. There are over 6000 different cenotes in the Yucatan Peninsula of Mexico alone for you to explore!

Snorkeling and Scuba Diving

Even on beaches with a lot of Sargassum seaweed, a short distance offshore the water is likely clear. In 2019 Scuba Diving Magazine voted the Riviera Maya the #1 place to scuba dive in the world. As well as the ocean, cenotes also attract cave divers who explore the extensive labyrinth of the caves. The scuba diving here is fabulous. And if scuba diving isn't you think then you have to go snorkeling in Akumal.

Or ask a Dive center to take you out to a large mat of Sargassum. Sargassum mats can make excellent dive sites because of the many critters living in them and the predators that hang out around them. "Diving under sargassum is like diving in another world," Billy Causey, Southeast Regional Director for NOAA's Office of Marine Sanctuaries.

Adventure, Theme & Water Parks

At various points along the Riviera Maya are several adventure and water parks. Such as Xplor, Xcaret, and Aktun-Chen. Activities include caving, snorkeling in underground rivers, ziplining, parachuting, rafting, driving ATV’s and amphibious vehicles through the jungle. You won’t find any Sargassum at these!

Sargassum Seaweed - In Conclusion

Although Sargassum seaweed in the ocean supports life and a unique ecosystem, it also threatens marine life close to shore. Increased seaweed growth affects all Caribbean countries. But the Mexican Government has made resolving this a priority. And in a variety of ways, it is tackling it. Fortunately, after the peak years of Sargassum Seaweed 2020 saw an 80% reduction. Leaving the beaches free for you and the turtles!

About Our Blog

Exploring The Riviera Maya is Ocean Breeze Akumal's Blog. Here we explore the diversity of Mexico's best tourism destination to highlight the best beaches, cenotes, restaurants, attractions, Mayan ruins, etc., etc. We provide information to help you explore this spectacular part of the world and give you tips and tricks that only the locals know. Helping to give you the vacation experience of a lifetime.

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Xpu Ha Beach- The Best Secret Beach In The Riviera Maya

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