Fish are an essential part of America’s swamp ecosystem, providing food for many reptiles and birds in the areas. They also help control the number of insect species for better balance in the ecosystem.
The species can vary significantly from tiny fish at the bottom of the food chain to much bigger predatory species. Minnows, bass, chain pickerel, and the mosquitofish can fall prey to larger predators such as bull and lemon sharks.
The water quality of swamps and marshy areas can vary greatly, and pools are also prone to drying out. This means they require several clever adaptations to survive. Some species can gulp air at the surface in poorly-oxygenated waters, some that can leave the water entirely, and others that aestivate in the mud.
In this article, we look at some fish you can find in swamps.
One of the critical swamp-dwelling fish is the mosquitofish. As the name suggests, it feeds on mosquitos, of which there are plenty in the Everglades and other major parks. The fish may be tiny, but it is plentiful and does an essential job in its place in the food chain. The fish will eat enough mosquito larvae to help with population control. A healthy number of mosquito-eating fish means that the swamp isn’t overrun. Simultaneously, these small fish are the perfect little morsel for many bigger fish and birds that live there.
You will also find plenty of minnows in the swamps and other wetlands. Minnows of different species are common baitfish because they are a plentiful and attractive lure for bigger species. The adaptability of these fish means that you can find them in other water areas, including some of the less-hospitable stretches. The bluntnose minnow, for example, has a high water tolerance so that they can survive in oxygen-depleted areas.
As these smaller fish regulate insect populations, we also need larger fish to feed on the smaller ones. Predatory carnivorous fish are abundant in swamps and can feed on a surprising array of creatures other than fish.
The chain pickerel is an average-sized fish that you can find throughout Florida. It reaches around 24 inches in length and uses its sharp teeth to eat smaller species. A much more significant threat in these waters is the Florida gar. The gar is larger at around three feet and has armored scales for protection. They are vicious, striking with great force and speed and thrashing their prey around. But, they also tend to hide in weeds in shallower waters to remain undetected.
The largemouth bass is another well-known and popular fish in Florida’s swamps and wetlands. This fish is in almost every watery habitat in Florida, from the swamps to the more brackish marshes and other lakes and rivers. It is a popular game fish because of its size of up to 24 inches. This species is even more impressive because it has a broad carnivorous appetite for snakes, frogs, bats, and water birds where possible.
When discussing predatory fish in the swamps and wetlands of North America, we have to discuss the likelihood of finding sharks in the area. There has always been the preconception that sharks are saltwater creatures who will only spend their time in the ocean. However, many species use osmoregulation to switch between salt and freshwater habitats. This allows them to come further inland to mangroves, swamps, and even further up the river. This could be to breed, provide a better nursery area for the young, or feed.
The bull shark is one such species. They can head inland into marshy areas and swamps to hunt, leading to sightings in the Everglades and some regions in Louisana. There are also stories about alligators attacking bull sharks, creating a fascinating battle between two very different apex predators. Bull sharks will also create nurseries inshore, as will lemon sharks. Lemon sharks commonly do this further off the Florida coast, with good numbers in the Bahamas. But, they are found in Florida and up into the Carolinas.
Another important consideration with these swampy areas of the southern states is that not all of these species are native. Some are invasive and could pose a big problem to indigenous wildlife by taking over their habitat or eating some species. The problem can get so bad that fishermen are even encouraged to kill any invasive species they come across to lower numbers and protect the natural environment.
One of the most interesting of these species is the walking catfish. This air-breathing fish can walk across the land to get to other channels and ditches in the stamps. This allows it to retreat from drying out pools and find better resources elsewhere. It originated in Southeast Asia but is now a problem in Florida because it has a habit of entering ponds and aquaculture farms to feed on prey.
It is similar to Asian swamp eels, which have been found in the Everglades since 2000. These creatures are different from our American eel and can reach up to three feet long. They are also dangerous to other native wildlife in the area and, like the catfish, can breathe air and survive if the area dries out.
America’s swamps would not be sustainable without our fish. Swamps and other wetlands need fish in the waters to fill that vital role in the food chain. Many that spend their days controlling the insect populations will also find themselves at risk from other fish, birds, or even humans. The variety of species, right up to the largest sharks, also shows that all kinds of aquatic life will find a way to take advantage of these waterways.
Bryan Harding is a member of the American Society of Mammalogists and a member of the American Birding Association. Bryan is especially fond of mammals and has studied and worked with them around the world. Bryan serves as owner, writer, and publisher of North American Nature.