What lives in "tidal" waters ?

[AndyS]

Like near New Brunswick, is it a dead zone. I was looking at the lower Raritan river on Google Earth and it is huge, just wonder what might be lurking in the "zone" between fresh and salt, then I guess I have to tides into effect also. The section of river is close to my home but I read few reports from the area (other than tackle boxes being stolen, etc.)
I looked around the net and it is hard to come up with anything. I have floated the upper stretches, I see alot of boat ramps on the lower end.
Thanx for the help.