Crayfish Ecosystem

Food Chain

• In a thriving ecosystem, a balance is always maintained so that there is enough food and resources for the creatures that inhabit it. Crayfish are an important part of their ecosystem and serve an essential link in the food chain. While some crayfish can live more than 10 years, most live for about two to four years. They are scavengers, feeding on both dead and live plants as well as fish and invertebrates. While adults prefer to feed on plants, the young crayfish prefer meat, feeding on snails, tadpoles and insects. Both young and old will not hesitate to eat other crayfish. Crayfish also serve as food for other creatures. Fish and birds eat crayfish, as do many mammals including raccoons. Approximately 240 species of wildlife in Northern America include crayfish in their diet.

Habitat

• Crayfish are found almost anywhere that there is water, from flowing streams to drainage ditches. There is even a variety that is found in underground water in caves. Except for the burrowing varieties of crayfish, they all need water to survive, and the water must be unpolluted. In fact, studying the health and size of crayfish populations is a good way to determine whether water is polluted. Crayfish do well in waters that are clean, while they die in water that is polluted. They need water that has a good oxygen supply so that they can breathe.

Shelter

• Since they are nocturnal, crayfish spend their days hiding under logs or rocks and come out to feed at night. Some types of crayfish live in underground burrows for their whole lives and only emerge in order to feed or mate. These burrowing crayfish dig tunnels that can be up to 5 feet deep in the moist banks of a stream. Sometimes they venture further and build their burrows some distance from the water surface, creating unwanted holes in the moist soils of golf courses.

Ecosystem Invaders

• When habitats are destroyed by erosion, dredging, silt buildup, pollution and dams, certain crayfish populations become stressed; about 65 different breeds of American crayfish are considered as either threatened or endangered. Another leading cause for the decline in crayfish populations is the arrival of nonnative crayfish into the ecosystem. This results in the transmission of crayfish diseases as well as a reduction in available resources as the nonnative breeds compete for food and also feed on the native crayfish. The Nashville crayfish, Oronectes shoupi, is an example of an endangered breed of American crayfish. It is found in only two creeks and has been negatively affect by sediment buildup due to urban development.