No. Caviar consists of processed, salted, non-fertilized sturgeon eggs.
Yes, caviar have to come from a specific type of fish. You can see a list of them at en.wikipedia.org/wiki/Caviar or ask.yahoo.com/20030306.html
Tuna do not come from ANY continent. Tuna are marine fish.
No, tuna is a separate species of fish.
That you're so broke you can't even dream about eating caviar.
No. Tuna is an actual fish.
It comes from tuna fish.
Sturgeon
Tuna is fish. A dolphin is a mammal.
egg plus fish
Caviar can be roe from more than just one form of fish (sturgeon is preferred), but it is common with squid.
Being a fish, tuna comes, and always has come, from the ocean.
Caviar comes from fish and is graded depending on which fish it came from.