The Merrimack River is one of the North Shore's premier striped bass fisheries. The river empties at Newburyport between the jetties, and the combination of a spring herring run and hard tidal current draws bass into the mouth and up the estuary in numbers.
The ground
Fish the mouth and jetties, where current and bait concentrate, and the estuary channels and edges upriver. The spring herring run is the marquee event, when bass stack to feed on the migrating bait.
How to fish it
Match the herring in spring with larger soft plastics, swimbaits and flies, and fish the current seams at the mouth. Jigs and plastics work the estuary edges. The mouth can be dangerous in an outgoing tide against an onshore wind, so fish it with care.
Mind the mouth The Merrimack mouth is notorious for dangerous conditions when a strong ebb meets an onshore swell, the bar can break hard. Know the tide and sea state, and do not run the mouth in sketchy conditions. Safety first.
Regulations Striped bass rules apply, and river herring are protected. See Massachusetts DMF.