True.
Step-by-step explanation:
The Union blockades were a part of a bigger plan called the Anaconda Plan. The Anaconda Plan had the purpose to "constrict" the Southern states so they could not have access to ports and supplies, then eventually split them into two.
These blockades had a very big impact on the South. The Southern states relied on outside goods and supplies, especially during the Civil War, so now that they had little to no access to ports and outside goods was devastating to the Confederacy.
The Southern states had very little industry compared to the North, so the lack of everything not only hurt the people drastically, but hurt the economy as a whole.