HERRING MONITORING

A spectacular migration occurs each spring in the Mystic River.

Each spring more than 1/2 million river herring migrate from the ocean up the Mystic River to the Mystic Lakes and to Horn Pond. If lined up back-to-back, this would measure up to 100 miles of fish!

For years, a volunteer-run bucket brigade hoisted the fish over the dam — one year they moved over 17,000 fish! Since 2012, the number of herring migrating up the Mystic River has grown from 198,000 to around 500,000. This remarkable restoration success story is the result of improved fish passage at the Mystic Lakes Dam in 2012 and at the Center Falls Dam in 2018, resulting in 200+ acres in expanded habitat for herring to spawn. The great news is that there are additional improvements coming to the fish passage at Horn Pond.

Learn more about this amazing return of the river herring on the Mystic here.

The Importance of River Herring

River herring have long been an important food resource for native people in this area. As a tradition, each year the Mashpee Wampanoag people watch the birds as a sign of the herring’s return. A Herring Day celebration at the beginning of the migration signifies the start of a new year and an opportunity to teach the next generation about the importance of the herring to tribal traditions. 

River herring play a crucial role in freshwater and marine food webs. They are prey for seals, and other marine mammals in the ocean; seabirds, cormorants, ospreys, herons, and eagles; tuna, cod, trout, and several species of bass; mink, fox, raccoon, skunk, weasel and turtles. As zooplankton eaters, they turn an inaccessible resource into the food for a large number of species humans consume, enjoy and profit from.

Lastly, river herring are one of few fish species that are diadromous (migratory between salt and fresh waters). Diadromous species make up less than 1% of all fish species.

Get Involved

You are invited to participate in this wildlife migration by helping us document the migration size. The more we know about the river herring the better equipped we are to advocate for a clean and healthy Mystic River, and for this unique species and the wildlife it supports. To do this we depend on community scientists to help us document the herring run size.

In-Person Monitoring. From April - June, more than 160 volunteers go out weekly to count herring at two sites in the watershed (Horn Pond and Mystic Lakes) in 10 minute blocks. This data is used by the Division of Marine Fisheries to estimate the annual run size. Recruitment begins in March for this program, and you can tell us you are interested in this program by filling out the volunteer interest form here.

“Fish-cam” and online platform. To provide even more data about the run size and behavior of herring, the Mystic River Watershed Association installed a “fish cam” at the upper Mystic Lakes and developed an online counting platform in 2017. Want to count fish using this underwater camera, learn more about river herring and the explore the data? Visit our Mystic Herring website.

MyRWA would like to thank the Massachusetts Division of Marine Fisheries. Massachusetts Department of Conservation and Recreation, Medford Boat Club and all of the volunteer monitors for supporting this program.

HERRING MONITORING PROGRAM RESULTS

2024: Estimated run size of approximately 640,000 herring

2023: Estimated run size of approximately 470,000 herring

2022: Estimated run size of approximately 425,000 herring, the largest herring run in the MA for this year

2021: Estimated run size of approximately 550,000 herring

2020: The decline in 2020 probably reflects lower reproductive success in the severe drought conditions of 2016. Herring runs across Massachusetts showed similar declines.

2019: Estimated run size of 789,000

2018: Estimated run size of 589,924 +/1 74,087 herring.

2017: 91,997 herring counted resulting in an estimated run size of 630,098 +/- 60,599 herring.

2016: 62,562 herring were counted yielding an estimated run size of 448,060 +/- 48,113 herring.

2015: 57,617 herring were observed resulting in an estimated 477,827 +/- 40,674 herring run size.

2014: 31,063 herring were counted resulting in an estimated 239,059 +/- 37,288 herring run size.

2013: 23,635 herring were observed yielding an estimated run size of 193,125 +/- 24,250 herring.

2012: 21,052 herring were counted by community scientists. Using modeling software provided by the MA-DMF, the Mystic River herring run was estimated to be 198,932 +/- 18,062 herring. This was the first year of the Mystic River Herring Monitoring Program.