A bright green underwater plant is creating major problems for thousands of people living in one of Colombia’s most important fishing regions. What began as isolated patches has expanded into a dense network of aquatic vegetation that now covers large sections of the lagoon, disrupting fishing, transportation, access to freshwater, and the local economy. For many residents, the invasion is more than an environmental concern—it is becoming a direct threat to their livelihoods and way of life.
The plant, Hydrilla verticillata, first appeared in northern Colombia around mid-2025. Native to Asia, it is considered one of the world’s most aggressive invasive aquatic plants. Hydrilla grows rapidly beneath the water’s surface, forming thick underwater mats that can spread from even tiny plant fragments, making it extremely difficult to eliminate once established.
Scientists are still investigating how Hydrilla reached the wetland. Possible pathways include maritime transportation through Colombia’s waterways or the release of aquarium plants into the environment. Whatever its origin, the plant encountered ideal growing conditions after arriving. Pollution and changing water flows have likely contributed to its rapid expansion. The Magdalena River carries nutrient-rich water, including untreated wastewater, into the wetland, effectively fertilizing plant growth. Local officials also say increased freshwater inflows have reduced the amount of saltwater that previously helped limit Hydrilla’s spread.
The consequences have been particularly severe for local fishing communities, where thousands of families depend on the lagoon for their income and food security. Dense vegetation makes it increasingly difficult for fishermen to navigate boats, reach traditional fishing grounds, and maintain normal fishing activities, placing significant pressure on the region’s economy.
Access to clean water has also become more challenging. Many residents rely on boats to reach freshwater channels connected to the Magdalena River, but some of these routes are now blocked by Hydrilla. As a result, communities are increasingly drawing water from areas closer to their homes, raising concerns about water quality, contamination, and potential public health risks.
The environmental consequences could be equally significant. Thick Hydrilla growth restricts water circulation, blocks sunlight from reaching native aquatic plants, and disrupts habitats for fish and other wildlife. Because the affected area is a UNESCO Biosphere Reserve and one of Colombia’s most important wetlands, scientists are closely monitoring the invasion and its long-term effects on the ecosystem.
So far, much of the response has come from local residents, who have been manually cutting channels through the dense vegetation to keep waterways open for boats. Government agencies have begun monitoring and removal efforts, but Hydrilla remains difficult to control because even small fragments can quickly grow into new plants. For the communities that depend on these wetlands, the challenge extends far beyond managing an invasive species—it’s about protecting their homes, preserving their livelihoods, and safeguarding a way of life that has sustained generations.
