How did the population of unionid mussels change after zebra mussels were introduced? Why did this change occur?

sample response:

The population of unionid mussels in the Hudson River decreased after zebra mussels were introduced. Zebra mussels, a nonnative species, competed with the unionid mussels for food. The zebra mussels were able to outcompete the unionid mussels, allowing the zebra mussel population to increase dramatically over six years. The unionid mussel population decreased due to a lack of food.

The zebra mussel known biologically as Dreissera Polymorph's, is a small freshwater mussel which its species was originally from the lakes in Southern Russia and Ukraine. Known globally as invasive species, they got their name through the striped pattern which are mostly seen on their shells.

Zebra mussels were noticed in Canada in the Great Lakes in 1988 at lake St. Clair. They were believed to be unintentionally released into the lakes in the ballast water of ships going to oceans, traveling the St. Lawrence Seaway. Another belief was linked to the introduction or release through anchors and chains even though this belief has been described as mere speculation.