Hundreds of fishermen yet to receive compensation after mass fish deaths. What is the verb on the sentence. And can I write HAVEN'T RECEIVED?

In the first sentence, there is no verb (so technically, it's not a sentence). It should really be: Hundreds of fishermen HAVE yet to receive....

Yes, you can write: Hundreds of fishermen HAVEN'T RECEIVED compensation after ... You can put YET either after HAVEN'T or after compensation, or just miss it out.

The verb would be the implied "have." Yes you can use "haven't received" or "haven't yet received."

Verb is a doing word so received You can write haven't received