Guest blog post by fisherman, retired Boston Globe writer and CRWA volunteer Nick King
WATERTOWN – There are lots of new commuters passing through town these days and they’re dwarfing by tenfold the human population of this community on the Charles River. The newcomers are river herring, and their annual spring migration is in full force, bringing hundreds of thousands of them into and up the Charles, many schooling below and above the Watertown dam.
State Fisheries Biologist Benjamin Gahagan estimates that in a given year, more than 300,000 alewives and blueback herring enter the Charles, not just a sign of spring but also testament to the improved cleanliness of the river thanks to conservation efforts by the Charles River Watershed Association and others. All told he says some 2 million river herring enter the Boston Watershed each year, including the Charles, Mystic and Weymouth Back Rivers.
Seagulls are fishing for herring in the Charles River.
The herring have a lengthy commute, travelling hundreds of miles in the salt water to get back to the Charles and its tributaries where they were born. This makes them anadromous, meaning they’re born in fresh water but migrate to the sea to live, returning to the fresh water only to spawn. It is thought that perhaps a third of them survive the spawning migration to return again to the sea.
The annual return of the herring is a natural phenomenon that triggers a whole series of other natural phenomena – and humans are included. The little fish are followed and pursued by bigger fish like shad and striped bass. Birds of all feathers congregate for the smorgasbord – ospreys, gulls, herons, you name it, it’s a wild aviary with the birds wheeling and diving with abandon at the teeming herring as they fight their way upstream. Meanwhile pedestrians traversing the walkways on either side of the river gawk, exclaim and snap photos of the legions of roiling fish as they try to flip themselves over the dam.
For hundreds of years up and down the East Coast, herring were a prized resource as food, bait and fertilizer. Today, their numbers are depleted enough that they are protected in Massachusetts and some other states. Dams are a major obstacle to the spawning and survival of river herring but attempts have been made to help ease their way up stream.
In 1972, for example, a fish ladder was installed at the Watertown dam, equipped with a series of 15 baffles to slow the cascading water and enable the fish to move up river. But it is now known that this fishway is located on the shallow side of the dam, so it is not nearly as accessible as it would be if it were located on the north side where the main channel lies.
Group of herring swimming in the Charles River.
Regardless, some fish do make it up the ladder and continue on their way to Waltham’s Moody Street dam which, like the three dams just further upstream in Newton Lower Falls, also has a fish ladder.
While this spring’s herring migration has unfolded in the waters of the Charles, considerable activity went on above the water as well. On May 31, a new pedestrian bridge was installed across the river just upstream of the Watertown Dam. The bridge arrived in four separate steel spans; two were connected together on the north side of the river and two on the south, then both double-length spans were lowered by cranes to meet and be bolted together in the middle. It’s Watertown’s version of the Golden Spike.
Once the new bridge is fully open, pedestrians will be able to look down and enjoy a bird’s eye view of the hordes of river herring commuting below.