OK I've been out a few times this year and only getting a few schoolies and yesterday hooked a few Catfish (hornpout?). Been using chunk Mackerel but not having much luck although others are bringing in keepers over 40". Only 2nd yr fishing and could use any advice as to where and/or what they are using. I have a boat and have tried different spots but very spotty with the schoolies. Thanks.....

We need to know what kind of tackle you are using. Rod length. Reel, Line weight, shocker, how it is set up?
Are you Anchored or drift fishing?
What tides you are Fishing, Day light or Nighttime, when you say Fishing spots, what do you mean.
What drew you to these spots?
What part of the Merrimac river are you Fishing?
I bet you did not think it could be this complex.

Any edges in current at the mouth of the river should hold fish, but this would apply up and down the river. By an edge, I mean things that will create eddies, reverse current, slow current next to faster, rips at narrows, etc. This might be as simple as the main channel dropoff, points at bends in the river, one of my favorites (especially if they hold herring runs) are where feeder creeks or smaller rivers enter the main river, mid river islands both up and downstream, wing dams or jetties, rock ledges, rock piles, individual rocks, holes in the river are also good spots but take close attention to electronics and some time to find.

If concentrating outside the river, I would look for ledge, both exposed with good water depth around it or sunken ledges. Rock is my favorite, big ledges in particular and what I like to look for is what I've foundly called toilet bowls. These are most evident when you have some big rollers coming in, but if you watch closely you will see them. These are specific spots on ledges that massive amounts of water will funnel into or push up on because of the shape of the rock at that spot and when it empties, it's like a big toilet bowl flushing. If the water around the ledge is blue-green, and you can see clearly down 15 feet in most spots, at these spots it will be white with frooth due to the turbulence and airation going on and you can see Jack-SH*t. Throw a 7 inch plastic jerkbait up on those spots and let them go with the flow when it flushes, braid is a huge plus here and I bet you hit some fish.

Last year was the first time that I had fished the mouth from a boat and it was fantastic. I only have a 16.5' but it handled it fine. I usually head down to the RI shore around Watch Hill but decided to try more north. We launched out of Hampton Harbor because we were not very familiar with the launches on the River and went and jigged up some mackerel off Sailsbury beach.
an interesting thing to try for the macks...if you can't find the fish try trolling slowly up and down the beach with the 4 or 5 hook mackerel rigs they sell with varying weights. have spinning rods ready cause when you find them you will catch all you need in a few minutes. we kept them alive in our well though the chunks worked just as well.
all we did at the mouth was set our boat so that we would not collide with anchored boats and then just free drifted. we fished there maybe 5 or 6 times last year and not once did we have to look around for fish. maybe we were just lucky!! hooked into a few cows that did a number on our light tackle but landed a lot of fish between 25" and 30". maybe around 30 or more fish a day for two guys. a few times we were stiffed on the macks so we pulled ashore and bought some surf clams or frozen macks. though not quite as good still caught a bunch of fish and had a blast. there are a sh!tload of boats so be ready to hear some screaming and yelling but the numbers of fish far out weighed the slight hassle.
Some tips:
1. make sure you have all the necessay safety equipment on board as the coast gaurd and EPO's love to patrol the area.
2. watch out for the deep sea boats if your boat is small..their wake is nasty
3. the rips can get pretty rough toward the outer edge so be careful
I don't know how the fishing is this year there yet but let us know how you do.