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Citizen Science

The Return of the River Herring

Each spring, river herring migrate from the Atlantic Ocean to freshwater inland streams (see Figure 1). The fish spend most of their life in the Atlantic Ocean, but they rely on estuaries and freshwater streams to migrate, spawn, reproduce, and grow. Coastal rivers along the East Coast of the United States historically supported seasonal river herring runs, and the rivers often appeared silver in color as millions of herring migrated upstream. Two species, Alewife and Blueback Herring, are found along the East Coast of the United States, and spawning spans from March to June. After the eggs hatch, the young remain in freshwater until late summer or early fall, when they travel to the Atlantic Ocean. In three to five years, the young herring will retrace the journey back to freshwater to reproduce. Like many species that rely on multiple habitats during migration, the river herring are vulnerable to threats (such as predation) during the annual passage from ocean to inland streams. To sustain the migration and meet the high-energy demands of the journey, the river herring consume zooplankton and smaller fish, as well as eggs and larvae of other aquatic species to survive. The river herring serve as an important food source for other animals including bald eagles, osprey, seals, otters, and even whales! Fish such as cod, tuna, haddock, halibut, and bluefish will also eat river herring, and healthy populations of young river herring serve as a food source for many sport fish including bass and trout. The river herring also serve as a bait species for catching lobster. River herring play essential roles in the ecosystems they inhabit throughout their life span.

Figure 1
|	FIGURE 1: River herring, including Alewife Herring (pictured below) and Blueback Herring, migrate from the Atlantic Ocean to inland streams each spring to reproduce.

River herring, including Alewife Herring (pictured below) and Blueback Herring, migrate from the Atlantic Ocean to inland streams each spring to reproduce.

Once abundant, river herring numbers have been decimated by human impacts. One such impact includes dams that were constructed along rivers to support industrialized mill operations. Over the last two decades, the population has experienced a 99% decline and is designated as a species of concern, falling to nearly endangered levels; however, the river herring are making successful comebacks thanks in large part to the science and community-based work of organizations including the Mystic River Watershed Association. This organization focuses on stewardship, water-quality projects, habitat restoration, community engagement, citizen science and more to protect and restore the Mystic River Watershed. Solutions such as fish ladders have been critical in their work (see “Project Blog Post” and “Fish Ladder Poster” links for fish ladder visuals). Fish ladders help to facilitate the movement of river herring so that they can once again navigate rivers impacted by dams to successfully reach their spawning grounds.

The Mystic River Herring Education Project from the Mystic River Watershed Association invites students to count river herring as the fish move through fish ladders. Nearly a decade ago, the organization led dam renovations and fish ladder construction projects to help facilitate the river herring migration. The results are encouraging, and your help is needed to document the population and its recovery. Underwater cameras have been added to help monitor the river herring migration as they use the fish ladders. With the help of technology, your students can engage in science beyond the classroom with the river herring citizen science project.

Project goal: Connect learners to the river herring migration.

Your task: Play a video and report the number of fish that you observe.

Science discipline: Life and Environmental Science

The Mystic River Herring Education Project is an online citizen science project with a user-friendly website full of information and resources to use in the classroom (see “Project Home” and the links that follow). To engage in the citizen science project, students will visit the project home page and watch short video clips of migrating river herring. While they view the video clip, they will count and record the number of river herring that they observe swimming from right to left on the screen. Once the video is complete, they will enter the total number of fish observed in that clip. Students are able to replay the video clips if needed. The video clips are generated from underwater cameras that film the river herring as they pass through a fish ladder. By counting river herring observed in the video clips, you play a key role in documenting the population and its recovery. The online citizen science river herring counts have enabled nighttime counts to take place; this online counting of the fish from the video clips is helping to account for many river herring that are using the ladder at night, which is not possible to see during in-person counts. This fun and meaningful project connects to a number of important life science concepts, and the fish ladders also help to highlight aspects of engineering and design practices.

After studying this fascinating fish and its amazing annual migration, and helping to document its comeback, we invite you to participate in Global Citizen Science Month (see Additional Resources). Held annually in April, Citizen Science Month serves as a springtime celebration of science. The monthlong event is coordinated by Sci-

Starter and the School for the Future of Innovation in Society at Arizona State University (ASU), with added support from the National Library of Medicine, the Citizen Science Association, Science Friday, and the National Geographic Society. Throughout the month of April, virtual events, webinars (including a weekly citizen science educator webinar series), and more will take place, and online resources including tutorials and certificates are available for educators (see “Calendar,” “Resources,” and “Tutorial” in Additional Resources). You are also encouraged to add your own events to the website! By participating in citizen science, your students will turn their curiosity into impact beyond the classroom.

Mystic River Herring Eduation Project at a glance

When: Anytime

How: Visit the project website (see “Project Home”) and click “Start Counting”

Where: Online/Global

Time needed: Variable, as much or as little time as desired

Special equipment needed: None

Cost: Free

Contact for more information:

Safety: As with any science lab, classroom, or field activity, always ensure that you are following recommended safety practices; for more information on safety in the science classroom visit


Project home—

About river herring—

Getting started instructions—

Student page—

Fish Ladder Poster—

Project link on SciStarter—

Project blog post—


River Herring Migration: A Mystic Ecological Success Story video—

Story map of the river herring success story—

Global Citizen Science Month—




Jill Nugent ( teaches science online, engages educators in citizen science experiences for the classroom, schoolyard, and beyond, and serves on the SciStarter Team. Follow SciStarter on Twitter: @SciStarter.

This column is the result of a partnership between SciStarter and the National Science Teaching Association. For more information about SciStarter and other citizen science projects, please visit

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