Last year I was fortunate enough to catch the tail end of the spring blitz down in Duxbury.
The last weekend of the month I spent Sat & Sun on the bridge and had a combined total of between 80-100 fish. You could see the river herring jumping out of the water every now and then.
(Of course the following week we had flooding rains, the first of a months worth, and the herring headed up to spawn.)