Thought I'd share my reply to an angler's questions about finding striped bass around the Sheepscot River and Back River up around Edgecomb. He was wondering about general suggestion for where to target fish, how important it is to add a fishfinder to his 16 foot skiff and how to find out about salinity levels in the rivers.
Rich - I have a couple of suggestions for you that might help.
How do you like to fish? Favor the fly rod or chucking spinning gear or drifting bait? If you are most interested in catching stripers on the fly then right now I'd concentrate my efforts on the shallow coves that abound in your area. They are all mud bottom, so you won't have great "sighting conditions" most days in terms of seeing fish. You will see them, though usually very close to the boat making for a tough presentation, and that can help you learn their patterns. What you really want to watch for is signs of fish - v-wakes, swirls, nervous water, fins, pushes of water. If you see anything on the surface that doesn't fit the general pattern of wind or current, assume it is fish until you learn otherwise.
Get out early and late. You want to be on a flat just before you can make out these signs on the water or squinting in the settling darkness to discern that tell-tail sign of fish. Target overcast or foggy days when the wind is calm and your time frame for seeing fish signs will be extended later into the morning or start earlier in the evening.
For this type of work, a simple pole (think canoe type pole) would help you push that skiff around quietly. A stern mounted trolling motor would be a better investment than a fishfinder if you end up liking the shallow water game.
Low incoming tide around first or last light is an excellent time to learn new areas. Second choice would be two hours before high or an hour or so after high, again, during periods of low light. At low water work the edges of the flats in just enough water to float your skiff. At high water cruise the edges of the marsh banks, over flooded grass and right against the ledges.
There are a pile of flats all within a mile of the Route 1 bridge that can hold fish.
Don't worry about salinity. There are random acts of bluefish violence all the way up the Kennebec above Bath and there's a lot more fresh water over there. There are very few of them around right now anyway, so you will be targetting stripers for the time being.
The deeper, faster moving water fishing will pick up once the juvie alewives start moving down river in good numbers. I was on fish yesterday AM from 4 to 5:30 that would occasionally come to the surface to smack herring, but even in these instances we did better going down to hook these fish.
Good luck and have fun exploring. If it was ten years ago when you were slaying fish around the reversing falls, the game has changed significantly, at least in the way that I approach it. The "old spots" and "old techniques" still work, but if that is the only way you think about finding fish, you'll have too many fishless outing. You just might find that catching two chunky fish that you "see" in two feet of water, requiring good stalking skills and the perfect cast, can be wicked satisfying.
Capt. Peter Fallon