blueback herring

Blueback herring

Alosa aestivalis

Blueback herring are sleek, metallic-blue fish under a foot in length, and are considered bait fish.


Blueback herring (Alosa aestivalis) are an anadromous species that spend the majority of their adult lives at sea, only returning to freshwater to spawn. They are sleek, metallic-blue fish, under a foot in length. Important ecologically to food webs in the watershed as adults and juveniles, and for recreational fishing, these migrants historically ranged as far upstream as Bellows Falls, 179 miles from Long Island Sound. They spawn in quick, shallow currents of the main stem river and its tributaries; also utilizing coves, juveniles then feed in the Connecticut’s currents until fall, when they return to the sea.

Fish Facts

  • Species type Anadromous
  • Size Up to 1 foot
  • Conservation High Concern
    A species of high concern is one that has been evaluated to be at risk of extinction or elimination fie to restricted range, few populations or occurrences, recent and widespread declines, severe threats or other factors.
  • Migration period April – June
  • Where to see them Moulson Pond, StanChem, Rainbow, West Springfield, Holyoke, Easthampton and Turners Falls dams

River population trends

Fun fact!

Historically, river herring (the collective name for Alewife and Blueback Herring) spawned in virtually every river and tributary along the Atlantic coast.

What do they look like?

Blueback herring are silvery in color and have a series of spiny and keeled scales along their bellies. They are characterized by the deep blush-green hue of their backs. With a black spot on their shoulder behind their head, they are difficult to distinguish from the alewife.

Where and when can I see them?

Visit Blueback herring from April to June at these dams:

Holyoke dam