What Role Do Manatees Play in the Ecosystem?

Often referred to as “sentinel species,” manatees are an indicator of the overall health of their marine ecosystems. As residents of both freshwater and saltwater ecosystems, typically slow-moving bays, rivers, coastal marshes and estuaries, manatees are quite susceptible to different environmental stressors. They are ideal indicators of any severe environmental changes that could have devastating effects on their ecosystems or habitats. Being predominantly aquatic herbivores, they play a critical role in the nutrients cycle and help clear the waterways by feeding on aquatic plants.

Core part of the ecosystem

Like other animals, manatees are merely a part of the much larger system where components are interdependent — remove one of the elements from the system and the whole system inevitably falls apart. In their ecosystem, manatees stop local vegetation from being obstructive by eating up massive quantities of plant life, up to 110 pounds of food per day. After eating huge quantities of sea grasses, the animals excrete all the digested flora in their surrounding environment and help recycle nutrients. Manatees do not prey on other animals, allowing other aquatic animals to thrive.

Opening up waterways

Eating up large quantities of marine plants makes manatees very crucial to canals, shallow rivers, salt marshes, bays and mangroves. Many of these nutrient-rich ecosystems are often clogged with overgrowths of hyacinth and other vegetation, supported by runoff fertilizers and outputs from sewerage treatment plants. As manatees eat up and clear these invasive vegetation from the waterways, they improve the health of their specific ecosystems. If the waterways were to be blocked by the invasive vegetation, there would be detrimental effects on other organisms in the water.

Returning to the same grass beds

Manatees also impact their ecosystems by repeatedly returning to the same places to graze. While they usually feed on the edges of these grass beds, they never forget where their food sources are located even after migrating to other areas. The constant “mowing” of seagrass helps to maintain the health of these grass beds. Likewise, their large body size ensures that they are able to influence the structure and function of their environments, not just as major consumers of aquatic plants and recyclers of various limiting nutrients, but as promoters and regulators of primary productivity.

Swimming with manatees is a unique, thrilling and remarkable experience. When you go out with our captains you’ll have an experience that you will remember forever. Knowledgeable in the nature, behavior and activities of manatees and on their interactions with humans, they’ll ensure you have a wonderful time with these fascinating sea cows. You also will have an opportunity to check out the beautiful scenery and connect with nature. For more information on manatees and manatee tours, visit the “Captain Mike’s Swimming With The Manatees” site.

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How do manatees contribute to the ecosystem?

Manatees are aquatic mammals that dwell in slow-moving, freshwater and saltwater bays, estuaries, coastal marshes and rivers. As purely aquatic herbivorous mammals, Florida manatees occupy a unique niche in the ecosystem. They play a vital role in the nutrient cycle. Moreover, they contribute significantly to waterway maintenance by actively feeding on aquatic plants. While they lack territorial behavior and intricate predator evasion strategies, manatees face no natural predators. Furthermore, they are absent from habitats shared by large sharks and killer whales, which are common predators of aquatic mammals. They are long-living animals with slow reproductive processes, low population growth and high susceptibility to over-exploitation by humans.

Food and Feeding

Florida manatees are opportunistic feeders, consuming over 65 species of floating, emergent, or submerged aquatic plants and grasses. They also consume leaves and shoots, along with seagrass beds found in both freshwater and seawater habitats. Additionally, they also feed on some fish varieties and small invertebrates. However, they do not actively pursue any fish, freshwater animals or marine animals. Engaging in grazing for 5 or more hours daily, manatees consume a substantial amount of vegetation. The quantity varies on their activity level and body size. Some can consume up to 8 percent of their total body weight each day.

Habitat and Ecology

Florida manatees are found in a variety of different environments, from the nearly pristine areas dominated by salt-marsh habitats and mangroves to the densely populated canal systems in urban settings. The mammals dwell in freshwater rivers, marine coastlines and estuarine bays, but are unable to tolerate extended exposure to low temperatures. They frequently migrate to warm-water springs, outfalls from electric power plants and various industrial facilities to avoid cold-related mortality.

Effects on ecosystem

Manatees’ biggest ecological contribution is recycling of various limiting nutrients, which promotes primary productivity. Their large body size means they are not only major consumers of aquatic vegetation, but also have huge influence on the structure and function of their environments. Manatee grazing is effective in mosquito and weed control, ensuring that waterways are not obstructed by overgrowth of vegetation. Manatees can serve as indicators of the ecological health of their habitats.

Predators and boat collisions

Since few marine animals are large enough to prey on them and the common predators of marine mammals such as killer whales, crocodiles and sharks rarely target them, manatees do not have natural predators in their ecosystems. In fact, manatees are large enough to be left alone by just about every other animal they encounter except for humans who have hunted them almost to extinction for their bones and meat. Manatees are also extremely susceptible to being hit by boat propellers, with many of them dying every year through boat collisions and human activities in their habitats.

Want to spend your day enjoying an extraordinary interactive outing with the manatees? At Captain Mike’s, we offer a unique opportunity for outdoor enthusiasts to see and swim with these gentle giants. Our experienced and knowledgeable guides will provide you with a pre-tour education video on passive observation, teach you how to achieve the best experience during your trip, take you out to the places where you can find manatees and provide you with a snorkel, mask and wetsuits. We will ensure that your manatee tour is completely safe, thrilling and memorable. For more information, visit the “Captain Mike’s Swimming with the Manatees” site.

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