Sea of Change

In the heart of the Atlantic Ocean, midway between the Bahamas and the Azores, lies the great body of water known as the Sargasso Sea. At first glance, the designation of this part of the Atlantic as a "sea" is a paradox, for no land boundaries mark it off from the rest of the open ocean.

Instead of being surrounded by a landmass, the Sargasso Sea is bordered by currents that keep this floating mass of seaweed in a constant state of flux, but more or less in place. With the Gulfstream to the west, the Azores current to the north, and the Canary, North Equatorial, and Antilles currents to the South and Southeast, the Sargasso Sea bends and stretches at the whim of moving currents and ocean breezes.

The Sargasso Sea, a name derived from the Portuguese word for seaweed, has a prevalence of seaweed or gulfweed floating over its surface. Old sailing legends and myths covered this area with strange monsters and islands of thickly matted seaweed, many miles in extent, making it a graveyard of missing ships.

In fact, this giant Seaweed bed is made up of large masses of floating plants, not one big impenetrable island. While there are places where the Sargasso has been measured to be several meters thick, for the most part, it is a thin layer of life on the surface of a vast ocean. Sargasso is home to hundreds of species of invertebrates, crustaceans, and fish. It provides shelter and food for many open ocean species, including Whales, Dolphin Fish, Tuna, Billfish, and more.

Only recently has Sagasso started impacting beaches and estuaries along the Southeastern United States, the Caribbean Islands, and the Yucatán Peninsula, as large patches ride the currents and breezes to our shores. Resorts along the Florida coast spend thousands of dollars to remove the stinky seaweed from their white-sand beaches, while less affluent locations deal with the mess as best they can.

Why this relatively sudden change in the habits of this floating mass? Well, we can look in the mirror and see the overall cause. Warming ocean waters due to climate change, and nutrient-rich waters from agricultural runoff have caused an almost 40% increase in the Sargasso Sea this year alone from the last record in 2022. This year's bloom is estimated to be over 31 million tons, stretching over 5,500 of ocean. In addition to man-made influences, blowing sands from the Sahara Desert, carried in high-altitude winds, add to the nutrients feeding the Sargasso.

So, why have you spent the last few minutes reading about seaweed in a fly fishing newsletter? Well, this Sargasso invasion is changing the feeding habits of some of our favorite saltwater species, and how we fish for them. We are beginning a new age of saltwater angling, where surface flies will be as important as the old standards.

Sargasso Grass is home to millions of invertebrates, crustaceans, and small fish that ride the waves like Penguins on icebergs, eventually ending up as part of the food chain hundreds of miles from where they were born. Blankets of Sargasso break into smaller rafts as they clear the reefs or are broken up by pounding surf. Sargasso crabs, the new favorite food of Mexican Permit and Tarpon, cling to bits of seaweed. Eventually, they are plucked from their floating home by fish that generally focus on prey hiding in the sand or coral bottom. The age of dry fly fishing for Permit has arrived.

This is the reality we experienced last week in Xcalak, Mexico, as we fished from the comfortable lodge, The XFlats. Floating Crab flies have been used in these waters for several years, pioneered in part by a young Mayan Guide, Tommy Haas (See the Silent Spotter video below), but on this occasion, conditions provided the perfect opportunity for success. Sargasso floated in with the tide and onshore wind, loaded with crabs. Permit hunted in packs, competing for these tasty snacks. Large "Lone Wolves" hunted alongside Tarpon racing from one floating mat to the next. All focus on crabs floating on the surface. 

On our first day, with only a few minutes left to fish, a large Permit swam in front of the boat, and Jennifer put her floating crab on target. The fish rose like a fat trout, and the battle was on. This experience played out several times during the week on other boats in our fleet. While not all were converted into fish landed, it proved that floating presentations were viable and, in some cases, preferred to traditional weighted fly presentations. To emphasize the importance, one of our anglers hooked six Permit in one day on floating crabs, bringing only one to hand, but that is Permit fishing.

It is hard to say how this influx of Sargasso will affect the habitat of the areas it eventually lands in, but it is easy to see that the resident fish species are adapting well to the new food source. In addition to Tarpon and Permit, Bonefish have been observed taking small crabs on the surface, opening the door for plenty of off-season creativity at the tying bench before our next visit to Xflats in 2026.

Unfortunately, alongside the positives of providing food for fish, birds, and other wildlife, there is a downside to excessive Sargasso blooms. If conditions remain for its continued explosion, the Sagasso invasion may become the norm as we move forward. Eventually, it will threaten more than the white sandy beaches of Miami and Cancun hotels; it has already smothered coral reefs and killed off Turtle Grass beds in the Caribbean, damaging critical habitat for resident species. If allowed to continue, we stand to lose more than we gain. It is a daunting task to reverse our impact on the planet, but one we should undertake if we want to see healthy coral reefs and white sandy beaches for our children's children.

Check out this Film Trailer about our friend Tommy....The Silent Spotter