Sesarma are a species of crab that are also called the purple marsh crab or marsh crab. They are nocturnal but sometimes will come out at daytime. Like the name suggests they are purple and have a carapace that grows to 1 inch long. Their carapace has a notch that goes along the middle. Their favorite food is marsh grass, which is why they are such a danger. The marsh grass is what is holding the marsh together and if it is eaten it could kill the marsh and the animals in the marsh. They are also known to occasionally prey on fiddler crabs. The marsh crab lives in burrows that they make in the mud of the marsh. One way to tell if there are marsh crabs around is if there is marsh grass missing in certain areas and lots of holes in the mud. The marsh crabs are dangerous because of how they disrupt the ecosystem of the salt marsh by eating at the marsh grass. If the ecosystem is disrupted populations of other animals can rapidly rise and fall. If the natural predators of the marsh crab are preying on it then it will be fine but if the predators are removed by a different animal such as humans the population of the marsh crabs can go out of control and destroy the ecosystem. The marsh crab can help the ecosystem or be a menace to it. If we take care of the ecosystem by limiting hunting and fishing then everything will stay in balance but if we do not limit the killing of animals for sport then we are disturbing the balance of the ecosystem which can have catastrophic results.