Florida’s Ancient Calusa Kingdom Was Powered by Ingenious Fish Corrals

Artist's impression of fish stored in watercourses.

Artist’s impression of fish stored in watercourses.
Statue: Florida Museum / Merald Clark

Despite not farming, the Calusa managed to dominate southwest Florida for centuries. New research suggests that this inventive Native American civilization built ‘watercourses’ to catch and store live fish, resulting in an abundant food surplus that allowed for socio-political complexity and ambitious construction projects.

The sprawling Calusa kingdom of Florida, which appeared about 2,000 years ago, stretched from what is now Tampa Bay to the ten thousand islands and as far east as Lake Okeechobee. Their capital, called Calos, was located near Fort Myers in a place now known as Mound Key Archaeological State Park.

Archaeologists have studied the Calusa for decades, exploring artificial islands made from discarded shells, the remains of former homes, and their impressive dredging channels. The Calusa are unique in that, unlike the Mayans, Aztecs and Incas, they never jumped on the agricultural wagon. These Indians were strict fisher-hunter-gatherers who relied almost exclusively on resources taken from the sea.

But somehow, the Calusa managed to fund ambitious construction projects, wield immense military power, and collect tribute along a network spanning hundreds of miles. These efforts would require an abundance of readily available food, leaving archaeologists wondering how these fisherman collectors could collect so much seafood and then prevent it all from rotting in the tropical Florida heat.

The two watercourses analyzed in the new study are located near two prominent mounds.

The two watercourses analyzed in the new study are located near two prominent mounds.
Statue: Florida Museum

New Research published in Proceedings of National Academy of Sciences offers some much needed answers, showing how the Calusa built coastal structures called watercourses, which they used to catch and store fish.

“What makes the Calusa different is that most other societies that achieve this level of complexity and power are primarily agricultural cultures,” explains William Marquardt, co-author of the study and researcher at the Florida Museum of Natural History, in a press release. “For a long time it was believed that societies that depended on fishing, hunting and gathering were less sophisticated. But our work over the past 35 years has shown that Calusa has developed a politically complex society with advanced architecture, religion, an army, specialists, distance trading and social rankings – all without being farmers. ”

Previous research stated that the watercourses were used to hold fish, but the new document is the first to provide a comprehensive and systematic analysis of these structures. For the new study, Marquardt and his colleagues tried to find out when the watercourses were built, how they were built, how they worked, and how their appearance coincided with other developments in the Calusa kingdom, such as the construction of huge buildings.

Two watercourses at Mound Key were analyzed in the study, both of which flank a canal measuring approximately 30 meters wide (100 feet) and approximately 600 meters long (2000 feet). Core samples with sediments were taken from the site, while external sensors provided a panoramic view of the hills. Other evidence, such as pieces of discarded shells and fish bones, was also collected and analyzed.

As the new research shows, the watercourses were built on top of a foundation of oyster shells. They were approximately rectangular in shape and occupy a space of about 3,345 square meters (36,000 square feet), which is about 62 percent of the size of an American football field.

To create the watercourses, the Calusa walled parts of estuaries, creating carrying capacity pens for fish. These walls, which stood 1 meter (3 feet) long, are made of shells and sediment. Nets or gates were probably used to prevent the fish from escaping. As the new evidence shows, the watercourses were not built haphazardly (i.e., piles of waste), but instead carefully designed structures. The construction and maintenance of the waterways was not an easy task and required “knowledge of tidal systems, hydrology and the biology of species,” the article said.

Caught in large quantities, the fish could be retained in the watercourses and then extracted for processing, such as smoking and drying. Evidence collected at the site shows traces of harder, pinfish and herring, all of which are fish species.

That said, the watercourses did not allow for long-term storage of live fish. Core samples taken from the site showed dark gray stains consistent with the accumulation of organic matter. This suggests that fresh ocean water did not enter the enclosures, apart from some splashes during high tide.

“We don’t know exactly how the courts worked, but our feeling is that storage would have been short-lived – on the order of hours to a few days, not months on end,” said Michael Savarese, a co-author of the study and a geologist from Florida Gulf Coast University, in the press release.

Artist's impression of the 'house', a large building that served as the political seat of the kingdom of Calusa in the 16th century.

Artist’s impression of the ‘house’, a large building that served as the political seat of the kingdom of Calusa in the 16th century.
Statue: Merald Clark / Florida Museum

The watercourses were built between 1300 CE and 1400 CE, according to the site’s carbon dating. This timing coincides with major upgrades to a large home known as the ‘house,’ the supposed home of Caalus, a Calusa king who lived in the mid-16th century. This structure could accommodate as many as 2,000 people and was the likely seat of power for “a long-lived corporate group” that dominated for about 500 years, the newspaper said.

Ultimately, the researchers linked the construction of these watercourses a burgeoning Calusa population, made up of about 20,000 individuals, and the emergence of complex political systems, such as the study describes:

The creation of [food] surpluses required overcoming significant challenges in the storage and distribution of products. Mound Key is in a subtropical climate, which would certainly have caused problems in maintaining excess stability and freshness, especially with animal products. We suggest that the Calusa of Mound Key was able to solve this unique problem in a very sophisticated way, including keeping live fish in water court depots. Construction of these facilities would likely require coordinated efforts and collective buy-in from larger segments of society.

Equipped with an abundance of food, the Calusa were able to support large-scale labor projects, generous parties and the emergence of other important institutions that “lead to greater investment in complex social and political formations,” the newspaper said.

But it wouldn’t be long. This civilization was at its peak when the first Europeans arrived in the New World, a development that turned the Calusa and many other Native American groups upside down.

Nevertheless, the Calusa remain a rare example of a civilization that achieves a high degree of socio-political complexity due to a lack of agriculture. If done correctly, and as the Calusa has shown, fish can power an entire kingdom.


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