Henryh“Have you ever eaten salmon? (To me it means throughout your entire life)
Have you eaten salmon yet? (To me it means eg at dinner the host asking me if I want to have some otherwise he will take away the plate.)”
This interpretation is basically correct, but the second one isn't really asking if you want some salmon.
Have you ever eaten salmon? does mean 'throughout your entire life'.
Have you tried the salmon yet? (This is more idiomatic with tried the. tried means tasted, taken a sample to eat. the salmon is that salmon which is available at the party, let's say.) This question is asked by someone who expects you to try the salmon at some time in the near future. Maybe you said earlier, "I think I'm going to try the salmon". So now people think you will eventually try the salmon. When they see you later, they ask if you have really tried it by this time: Have you tried the salmon yet?
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Henryh “I have never ridden a camel.
I haven't ridden a camel yet.”
I have never ridden a camel. (in my whole life)
I haven't ridden a camel yet (during this outing at which we all intend to ride a camel). (My turn to ride a camel has not yet come, though I expect to take my turn riding a camel soon.)
-- What animals have you ridden?
-- I have ridden a horse.
-- Have you ever ridden a camel?
-- No. I have never ridden a camel. But it's strange you should ask. I am going to Egypt on vacation. My family and I are going to ride camels while we are there.
-- So you haven't ridden a camel yet!
-- Right!
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To summarize: have ever? / has ever? / have never / has never relate to all time before the statement is made. have ... yet? / has ... yet? / haven't ... yet / hasn't ... yet relate to the near future in which some action is expected or intended.
CJ