The black crappie has a variety of interactions with other organisms.  Some of these interactions are commensalistic, some are predatory, some are parasitic, and others are mutualistic.  Pomoxis nigromaculatus requires many of these interactions to survive.

Commonly the black crappie is found in bodies of water where carp reside.  The carp tend to destroy thick vegetation, which results in clear and nutrient-poor water that Pomoxis nigromaculatus prefers.  Because the black crappie benefits while the carp remain unaffected, this is a commensalistic relationship. 

                                                                                                                            
              

                                                     




                       
                                    A common carp swimming.  Photo taken by                                              More common carp swimming in a lake.
                                                         Микова Наталия                                                                                   Photo taken by Leonard G.

To learn more about the black crappie’s habitat, click here.

The black crappie has a mutualistic relationship with many bacteria that are found in its digestive tract.  Many of these bacteria help to break down the chitinous exoskeletons of the aquatic insects that Pomoxis nigromaculatus consumes.  The bacteria benefit because they have a relatively stable environment in which to live, and Pomoxis nigromaculatus benefits because it can consume organisms with exoskeletons that are difficult to digest without experiencing indigestion.
                
To learn more about the black crappie’s nutrition, click here.

The black crappie feeds on, and is fed on by, many different organisms.  As they grow in size, black crappies typically consume aquatic insects, zooplankton, and small fish, such as immature bass, bluegills, and perch.  Younger crappies eat 
zooplankton, aquatic insects, and insect larvae.  Although 
they can be voracious predators, Pomoxis nigromaculatus 
act as prey to many organisms in the aquatic food chain.  
They are often eaten by blue herons, large muskellunges, 
northern pikes, otters, and snapping turtles.  In order to 
discourage predation, black crappies often travel in 
migratory schools.  
                                                                                                                                       A blue heron eating a black crappie.  Photo
by John Cossick (U.S. Fish & Wildlife Service).

There are many parasites that inhabit Pomoxis nigromaculatus, but two of the most common are Haplocleidus dispar and Cleidodiscus vancleavei.  These two parasites are trematodes, or parasitic flukes, that can be very destructive to black crappies.  These two species require two hosts to complete their life cycles; one is generally a mollusk while the other is a member of the sunfish family (Centrarchidae).  When a fish such as the black crappie is infected with one of these parasites, they often establish themselves in the gills.  The gills of the black crappie then become clogged with the parasite, which causes extreme difficulties in respiration and filter feeding.  Eventually the affected individual can die due to its inability to acquire sufficient oxygen.
                
To learn more about respiration in black crappies, click here.

                                                                            
Me and my grandpa catching a black 
crappie at Serpent Lake. Photo taken 
by Kurt Jacobson.

                                                                 
       
To learn about some of the black crappie’s adaptations, click here.
To learn more about other organisms at multipleorganisms.net, click here.
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