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RESTORING FISH RUNS
Restoring Anadromous & Catadromous Fish "Runs"For thousands of years, migratory fish species such as American shad, blueback herring and alewife (another type of river herring) swam far up Massachusetts’ coastal rivers each year to fulfill their biological imperative of spawning (laying their eggs) in fresh water. Rainbow smelt are another ocean species that spawn in our coastal rivers, though generally in the brackish waters that are affected by ocean tides. “Catadromous” species like American eel spawn in the ocean and then move to freshwater to live.These fish were a critical food source for Native Americans and early colonists alike. Native Americans in southeastern Massachusetts would plan their own seasonal movements with the spawning runs of herring. Spring fish runs were so plentiful – virtually solid masses of fish extended from shore to shore -- that colonial farmers depended on them to fertilize their fields. In the seventeenth century, Israel Stoughton began to build a dam on the lower Neponset River to harness water power to run his mills (it was the second dam built in what is now the United States). So angry were upstream farmers from Norwood that they marched all the way to Milton and Boston, where the dam was being built, and tried unsuccessfully to tear it down. So began the long battle waged first by farmers and then by conservationists and fish biologists to restore “fish runs,” the rivers and streams that for centuries were used by anadromous and catadromous fish. Literally thousands of old mill dams remain on our rivers and streams today, remnants of our industrial past that no longer serve any useful purpose. Click here to learn more about other negative impacts of dams. Dams are so disastrous to fish runs that every anadromous fish species is in severe decline (although over-fishing, water-pollution and other factors play a role as well). The decline in these species also harms their predators, including popular salt water sport fish such as striped bass and bluefish. Herring and shad are also an important link in the larger Gulf of Maine food chain that supports numerous commercial fish species, including cod. Restoration of fish runs would not only help these sport and commercial fish rebound, but would also have a beneficial effect on the overall ecology of rivers and streams, extending the range of birds such as eagles and osprey, to name just a few. One key question for conservationists trying to restore fish runs is the effectiveness of fish ladders and ramps, which are designed to get some adult fish species over dams in the spring and juveniles back to sea in the fall. Oddly, these devices sometimes work on one river while the same devise is rejected by the same fish species on another, and biologists don’t know why. Also, fish ladders and ramps generally do not work for all species of anadromous or catadromous fish that may have once spawned in a given river or stream. They may be used by strong swimming species like herring, be problematic for the more skittish shad, and be unusable for smaller fish like smelt. Nevertheless, there have been many successes, including the fish ladder that gets herring around a dam on the Nemasket River (part of the Taunton River Watershed) in Middleboro. These devices are often less controversial than dam removal (especially where people now live on ponds that form behind dams) and can occasionally be cheaper than dam removal. Fish ladders and ramps are quite common, often successful, and should not be rejected out of hand by those who want to restore our native anadromous and catadromous fish runs. What You Can Do to Help Remove Obsolete Dams and/or Restore Anadromous Fish PassageWork to remove dams that are harming your local rivers and streams or to provide fish passage over them.
Work for state dam removal legislation and fundingAsk the Governor and your state legislators (if you don’t know who your legislators are, go to www.wheredoivotema.com/bal/myelectioninfo.php):
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