In honor of World Fish Migration day on Saturday, Oct. 24th, students Rebecca Colby ’21 Ph.D, Kayla Morin ’19 MS, and Peter Goggins ’21 (CAHNR) of ecology and evolutionary biology professor Eric Schultz’s fish lab contribute this column about river herring, the fish you didn’t know you needed.
A quick web search for river herring will reveal that everything from schools to breweries to train stations are named after these once-iconic, though unassuming, fish. The name “river herring” refers to two species of fish: Alewife (Alosa pseudoharengus) and Blueback Herring (Alosa aestivalis). These fish were an everyday staple for Northeasterners from the pre-colonial era through the First World War. The ease with which they were caught and preserved made river herring an important food source before refrigeration. If your grandparents lived in New England, they may have developed a taste for these fish, in the direct legacy of indigenous peoples. Even today, schoolchildren are taught the story of indigenous peoples, such as Tisquantum (Squanto), teaching the Pilgrims to survive the harsh winters by seeding and fertilizing crops with fish, most likely river herring. It was inevitable that these fish became ingrained in the lore of local cultures – billions of fish frantically swimming upstream every spring can hardly go unnoticed, let alone unexploited.
And exploited they were. Coalescing into large schools and being predictable in both timing and route, migrating river herring were easily harvested by the hundreds of thousands. Spanning Canada to South Carolina, river herring were used for bait, fertilizer, animal feed, and supper. Early records from the 1600s suggest their numbers were already in decline and, accordingly, some of the earliest laws in American colonies tried to address overharvest. Even so, commercial harvest reached its peak in 1958 at 74.9 million pounds of herring, eclipsing any sustainable limit. And, after the initial population collapse, the overall fishing rate remained 20% higher than sustainable levels for many years. Today, we see river herring populations in perilous condition, having lost billions of their numbers due to overfishing and other human activities.
Atop their laborious migratory lifestyle and the ever-present fishing pressures faced by river herring is another perennial and long-standing challenge for these fish: passage. Dams and other human-built structures have obstructed fish passage through waterways for centuries. But now, there’s a new player in town — drought. More and more, streams are drying up during summer months due to increasing human demands for water and worsening droughts from climate change. This past summer alone, UConn researchers identified six locations where water shortages trapped ready-to-migrate juvenile river herring in freshwater. The ramifications of these “stranding” events are not yet known, but the prospects for hungry river herring trapped in freshwater habitats with diminishing food supplies are poor. It is highly likely that preserving fragile river herring habitats and fine-tuning the ability to predict locations most impacted by droughts will be critical to conserving these species.
People sometimes ask: Why conserve this modest-looking, obstacle-facing fish, anyway? One overarching reason is shared by economic, cultural, and ecological appraisers alike, and that is volume. The case for river herring is always predicated on the massive abundance of these singly-forgettable fish. A single returning river herring does little good for the ecosystem of its natal, freshwater habitat, nor for the bottom line of a commercial fishing vessel. Whole schools, however, can support populations and shape economies.
Though the time of bringing home river herring for supper has come and gone, human need for these fish is more pressing than ever for use as animal feed and fish oil. They are critically important in Maine, where use of river herring as bait in lobster traps is common. In this role, river herring make an incalculable contribution to the local economy, which carries into proximate communities through shipping and trade. Demand for products that utilize river herring is projected to increase in coming decades but, due to past overexploitation, some New England regions now restrict or altogether prohibit the harvesting of river herring. Instead of being able to take advantage of a revenue source, New England states are left playing catch-up as they struggle to preserve the remaining stocks of river herring in their area.
In addition to conservation via legislative efforts, managers across New England work tirelessly to strengthen populations by moving some fish from robust populations into needy locations, one water-filled truck load at a time. In some cases, this method has even been used to reestablish previously exterminated populations. Cooperatively, researchers are working to understand which freshwater locations are best suited for successful, lasting benefits from stocking efforts. With limited resources, personnel, and funding, maximizing return on investment is critical to fisheries managers if there is to be hope of river herring rebounding.
For millennia, river herring have persisted along the Northeast coast of North America and made an indelible mark on local cultures. The modern New Englander may not rely on river herring to survive the winter nor spend enough time observing nature to notice the adult fish struggling upstream every spring, but the fundamental importance of these fish remains. Even aside from the cultural and historical legacies of river herring, it is undeniable that the very existence and seemingly limitless abundance of these fish contribute greatly to the region’s welfare. Through both direct economic use as an exploitable natural resource and critical role in the food webs of native environments, these fish support communities, livelihoods, ecosystems, and industries. For far longer than any record of their existence, river herring have roamed the oceans and streams of this region, contending with danger and hardship from all directions while engaged in a titanic struggle to survive and reproduce. The rise of industrial society only exacerbated these problems and pushed river herring to their breaking point. Now it is our turn to support them. Considering all they’ve provided us, we at least owe river herring a fighting chance.
Want to learn more about river herring or do more to support their conservation and research? Check out these links and resources: