Two species of fish in coastal Massachusetts are collectively referred to as “river herring.” They are the alewife (Alosa pseudoharengus) and the blueback herring (Alosa aestivalis). They are very similar in appearance and both species are anadromous, meaning they are born in freshwater, spend the majority of their lives in the ocean, and return to freshwater to spawn. Mature river herring undertake an upriver spawning migration in the spring. In Massachusetts waters, alewives spawn in late March to mid-May when water temperature reaches about 51ºF. Blueback herring spawn later in the spring (late April through June), when water temperature reaches about 57ºF.
Jackson Square Dam and Fishway is located in Weymouth’s Jackson Square, the herring run has played an important role in Weymouth’s history as the herring was both a prized and protected resource. The herring run centers around a so-called “fish ladder” – a series of steps where the river pools to make it easier for the fish to swim upstream – built by the state in the 1940s. The run begins at Whitman’s Pond, and flows through and under the Iron Hill area, passing under Commercial Square. It flows past the town incinerator, into Back River and out to sea.
A pair of murals by local artists depicting the run’s prominent place in Weymouth history now hang from what used to be the bare back wall of The Venetian Restaurant. Two kiosks at the park provide information on the different species that swim in the river and some important dates in the run’s history.
*Congratulations to gabby812 on FTF!*