Presently, there are no estuaries, deltas, or large rivers
near me. The few rivers are barley navigable. My limited
exposure was as a kid in and around the Chesapeake Bay and
some swamps in the mid-west.

I guess you would want a boat with a shallow draft or a
retractable keel. Sail power is an advantage, but have a very
reliable motor or engine to get you out of trouble fast.

I used to catch numerous fiddler crabs but never ate them.
If you chase them, they run into a hole. You can wait for
them to come to the surface to "take a look"; you immediately
plunge a stick (flat is best) at a 45 degree angle into the
adjoining soil, but pointing toward the tunnel and this
will block their escape. Now dig up the crab.

Agree, that pollution is a real problem that is hard to
analyze. Piracy is on the up-swing, so piracy copy-cats
or piracy wanna-be's will increase. Corrupt LEO's can
harass you or confiscate you boat.

Sailing, coastal sailing, fishing, and coastal scavenging
is a whole different world. I have seen articles written
on this life-syle, but I cannot remember where. There must
be other sailors doing this life-style and forums where
you can learn some tricks of the trade.