Friends and Foes
straight to the silver carp skipping two crucial trophic levels. This puts the silver at direct competition with the native species not only at the first trophic level but at the second and third as well. The gizzard shad is a great example of a smaller sized fish that have their main source of food as phytoplankton. The gizzard shad is a primary food source for many larger fish that make up a lot of the Mississippi River System.
If you haven’t figured it out already, with the numerous numbers of silver carp eating the majority of the phytoplankton this is decreasing the number of gizzard shad and in turn hurting the native large fish population as well. This is what makes the silver carp so dangerous because they eat out the main food source to smaller fish that are important bases for the food chain. On the left hand side of the food web a brief Michigan Lake system food chain is represented. As of April 2010 there are not silver carp in Lake Michigan, in 2009 there were traces of DNA found, however actual silver carp in Lake Michigan have not been confirmed. This food web is more of a predicted food web based on its prey and its role within the Mississippi water system. It is believed that is would essentially have the same effect within Lake Michigan. The alewife is similar to the Mississippi River’s gizzard shad, where it is a primary consumer of phytoplankton and is the main food source for the larger fish in Lake Michigan.
The silver carp is having an impact on many different species in the right hand column a few of these organisms are shown. Hint - if you click on the word next to each thumbnail you will be taken to my classmate’s sites to find out more information about each organism in greater detail.
Obviously the silver carp has a different interaction with each of the species shown, by reading throughout the site you probably could figure out how, however, if you haven’t I’ll make sure I help you out just jump into the right margin!!!
Quick Facts
Food Source for Silver Carp:
Phytoplankton
Directly Competing species:
Gizzard Shad, Alewife, paddlefish (filter feeders)
INDirectly Competing species:
Larger fish (non-filter feeders), birds
INTERACTIONS:
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The silver carp’s relationships defined:
White pelican: If you check out the food web you can see the eagle on the right hand side at the top of the food chain, because of the silver carp eating phytoplankton this puts it in direct competition to small fish within the river system. Small fish that would usually be utilized by the pelican for food!
Common Shiner & Yellow Perch: The silver carp eats its main source of food: phytoplankton
Paddlefish: Another filter feeder! The problem is that the number of silver carp are so numerous that they are eating the majority of the food supply that normally would be eaten by the endangered paddlefish and other species.
Muskellunge: The Muskellunge’s main source of food is smaller fish, the population of these smaller fish are depleted due to lack of food eaten by the silver carp.
Interactions with other species
This food web is representative of what the potential Lake Michigan food web would appear to be as well as what the Mississippi River System food web is. For the purposes of showing what the carp is doing throughout both these systems it is placed by the tertiary consumers even though it is a primary consumer. Made by Me.
Photo by Kate Gardiner
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Picture by: Great Rivers Study
Silver Carp leaping out of water.
