Yet vs Whereas

[Volcano1985]

Humans depend on these teeming waters for comfort and survival, yet global warming and overfishing threaten to leave the ocean agitated and empty.

Can we use whereas instead yet in this sentence?

[Cerberus™]

You could use it, but it would not be the best choice here; if you ask me, simply "but" is better. Whereas is more specific: it "tends to contrast opposite sides of a single quality in two similar things", not just any pair of opposed clauses. See:
http://sana.tkk.fi/awe/cohesion/signposts/contrast/subordinator/whereas.html