Invasive Species
Invasive Species are organisms that don't belong. They are plants or animals that travel from another place. Sometimes peple bring them by accident. Sometimes people bring them on purpose. They come to a new ecosystem. The ecosystem can be damaged by them. They may have no natural predators. So they have babies, and very few of them die. Very soon, there are too many of them. They use up the resources. The native organisms die. They are crowded out.
The Chesapeake Bay has some invasive species. The Blue Catfish is one. The Blue Catfish came from places like the Mississippi River. There is nothing in the Chesapeake Bay that eats the Blue Catfish. The Blue Catfish eats many kinds of fish. It is using up resources that native species need. Zebra Mussels are in the Chesapeake Bay Watershed. They come from Russia. Zebra Mussels damage boats and water treatment plants. The Northern Snakehead is also in the Chesapeake Bay Watershed. It is a fish from China. Nothing here will eat it. It has a big appetite, and eats many native fish. Mute swans came from Europe and Asia. Mute swans pull up underwater plants which fish need to survive. Phragmites are tall grasses that came from Europe. They grow so close together that they crowd out native marsh grasses.
People can do a few things to prevent invasive species. If a person is bringing a boat from another body of water, he or she can clean the boat before bringing it into new water. Zebra mussels came on boats. People should not put plants or animals from aquariums into streams or bays. Northern Snakehead fish came from people releasing them into lakes and ponds. Phragmites were planted on purpose in people's gardens. Then they spread to wetlands. People should use plants that are native to Maryland to avoid this.