The South Atlantic Ocean’s Sargassum Problem-South Florida and The Florida Keys 

The South Atlantic Ocean waters off the Florida Keys are known for their intense concentration of offshore pelagic fish species like dolphin, tuna, and wahoo. But fishing might be rougher than usual this spring and summer because the South Atlantic Ocean may see the worst-ever sargassum bloom. 

2023 Recording Breaking South Florida Sargassum Bloom?

The South Atlantic Ocean has experienced a dramatic increase in sargassum – a type of large seaweed – washing up on its beaches since 2011, with 2018 being the worst year on record, but is that about to change?

Sargassum South Florida Record Breaking Year


According to the University of South Florida researchers, it is likely that 2023 will be record breaking sargassum year off the Florida Keys and South Florida. In a recent statement, the researchers stated that January 2023 is more significant than what we saw during the peak times of July and August,” said Brian Barnes at the University of South Florida’s optical oceanography department. For detailed information, check out this bulletin:

This rotting seaweed does more than increase the amount of seaweed biomass:

  • It heats the ocean surface and interferes with natural processes like bait feeding on sargassum.
  • Block sunlight from reaching coral reefs resulting in coral bleaching. 
  • Changes in fish migration patterns.
  • Economic losses from decreased tourism revenue have been exceptionally hard-hitting for communities that depend on these industries for livelihoods.

If you are planning a trip to any of the Southern Caribbean  then I highly checking out checking out

EL Nino and the Sargassum Problem in the Atlantic

Scientists are still trying to determine the cause of this sargassum influx, but one potential explanation lies in correlations between it and El Nino events.

El Nino is a climate pattern that occurs when water temperatures in the Pacific Ocean become warmer than usual due to changes in atmospheric circulation patterns. It is likely linked to increased nutrient inputs from rivers, leading to more favorable conditions for sargassum growth.

Studies have determined that sargassum production increases dramatically during El Nino events, which can result in higher concentrations washing up along certain coasts depending on ocean currents. For example, large blooms of sargassum were sighted near the shores of all the South Caribbean islands when El Nino occurred between 2011-2014, coinciding with the start of the South Atlantic’s sargassum infestation.

As I mentioned in a previous blog, How to Catch Mahi Mahi, In 2011(the start of the El Niño), this increase in dead sargassum weed was directly correlated with a decrease in the number of migratory mahi-mahi observed in South Florida. Scientists believe the massive biomass of dead sargassum has interfered with the mahi-mahi’s ability to find food. 

Key Largo Fishing Charters

In 2011, local charter boat captains and commercial anglers began to observe a distinct shift in the timing of mahi-mahi migrations. Whereas they had previously seen these fish arrive during late spring and early summer, they noticed that mahi-mahi appeared in more significant numbers later in the year, around August and September, after the tourism season ended.

In addition, the vast amounts of sargassum have made it difficult for the fish to follow their natural migratory patterns along ocean currents, putting them at risk of being caught in longline gear. As a result, this may be why we are seeing less mahi-mahi in the Florida Keys and other parts of the Gulf Stream ecosystem.

All animals, including birds and fish, will change migratory patterns based on environmental stresses.

It is clear that El Nino is playing a significant role in sargassum problems in South Atlantic Ocean off the Florida Keys; however, like with anything else, who knows?

Check out this report issued by Dolphin Research Program on February 2nd 2023.  Does this mean the Florida Keys will see a late arrival of spring time dolphin in 2023?

Key Largo Deep Sea Fishing Charters

Africa Wildfire Season=More Saharan Dust=More Sargassum

From the way it appears on the satellite images the sargassum weed is blooming off the coast of Africa. So could the South African coast be the root cause?  I highly recommend using Simar Conabio to monitor the progress of the weed.  The African fire season typically starts in September and lasts until March. However, vegetation is dryer in the southern hemisphere from April to August, and temperatures begin to rise significantly – making conditions prime for wildfires.

Current views from space show that the potential root of the South Floridas sargassum problem could be the river run-off from the West Coast of Africa Guinea–Bissau river estuaries.

South Florida Sargassum Problem

In some cases, African farmers manufacture these fires. The farmers clear to land by cutting down vegetation and setting fire afterward as a cheaper way of preparing for future crops. Although this method has benefits, such as killing pests and diseases and providing plant nutrients, it is linked to deforestation and soil erosion, creating more Saharan Dust. If you want to learn what is happening over in Africa with the wildfire season and how it perhaps might be a significant contributor to the sargassum bloom, then check out his article:

Studies from leading environmental organizations show that Saharan Dust is one of the main culprits behind these South Atlantic sargassum blooms. Winds from over Sahara deserts have brought large amounts of dust particles that accumulate in the ocean and promote conditions for sargassum growth. This cyclic process has resulted in years where it is exceptionally prominent – such as the one we’re experiencing right now.

No Krill-No Bait Fish-No Mahi Mahi-No Whales

Krill are small crustaceans that provide a crucial food source for baitfish like flying fish, mahi mahi, and especially tuna. 

Krill are particularly vulnerable to environmental changes due to their small size and slow reproductive rates. As such, any threat posed by sargassum could seriously affect entire ecosystems.

While research into this topic is ongoing, some recent studies suggest that increased concentrations of sargassum may harm krill populations in some areas of the South Atlantic Ocean, given its potential implications for marine life and broader ecosystems.  

Our current United States government administration is quick to point fingers and wants speed limits in place for boats off the east coast of the United States, blaming boats for the killing of whales, but are boats really the root cause? Whales eat krill—something to ponder. No krill-no whales. 

The Good Karma Rigging Crews: Insider Tips For Fishing In Heavy Weed Cover

Fishing off the Florida Keys this spring and summer might be tricky due to the sargassum. But don’t let the heavy sargassum weed cover discourage you – with a little hard work and intelligent strategizing, you can still make this season one to remember.

The best way to tackle sargassum is by being prepared.  If you’re a member of one of the Good Karma Rigging Crews (1 and 2), then you have access to insider tips from myself on how to fish in heavy sargassum weed cover. 

If you’re a member of one of the Good Karma Rigging Crews (1 and 2), you can access insider tips on tackling this sargassum cover. Through our private Facebook group, I’ll share all my secrets on fishing in heavy weed cover, from scattered sargassum mats to larger ones. In addition, new to 2023, my rigging members will get information about dolphin fishing locations and depths off Key Largo and Islamorada, including GPS coordinates to offshore humps and rips where these fish usually can be found.

Plus, during mahi mahi season, you’ll get exclusive access to data on actual depths they are swimming at and my historical spots based on time of year and satellite images of weed lines and temperature breaks.

If you want help preparing for a challenging but rewarding spring and summer fishing season, join one of the Good Karma Rigging Crews! With my insight into heavy weed cover off Key Largo and Islamorada, you can ensure your catches stay plentiful despite any obstacles. If you are interested in joining the rigging crew you can email me at The private groups are for recreational fisherman only.


Those who do the work will catch fish this summer in the sargassum, and those who don’t will see much except weed. Being mindful of changing ocean conditions and ensuring your tackle can handle heavier weeds are other considerations when fishing under these circumstances. Even if it takes more time and effort than usual – staying persistent and paying attention can lead you to a successful day of the Florida Keys offshore fishing.