Headway for herring at the Orleans run
By Judy Scanlon
Posted Nov 30, 2018 at 3:01 AM
With an estimated run size this year of over 28,000 herring, the Pilgrim Lake herring run in Orleans has regional significance as the second-largest river herring run in the Pleasant Bay watershed.
River herring (alewife and blueback) are referred to as a “keystone species,” vital to the marine, estuarine, and freshwater food webs.
River herring populations have undergone a significant decline, largely due to impaired water quality, overfishing, and lost or restricted access to important upstream freshwater spawning areas. Protection of historical spawning habitat like Pilgrim Lake and improvement of fish runs are critical to survival of the species.
Once privately owned, the Pilgrim Lake fishway is thought to date back to the 1930s. The town purchased it long ago, taking over responsibility for its management.
The original structure consisted of 17-foot long concrete fishway that had deteriorated over the years, impeding herring migration into the lake.
In a significant state-town planning and funding collaboration, Massachusetts Division of Marine Fisheries (MA DMF) designed an improved weir and pool fishway system, increasing the number of number of pools along the run from one to six, creating rest areas for the herring.
Next, using a cofferdam to control water flow, the old fishway was demolished, and new concrete walls were poured under supervision of the town’s Department of Public Works.
The new run was completed last October and is ready for next year’s herring migration.
Next spring, as a final part of this project, the MA DMF will install a new electronic fish counter purchased by the town.
Since 2008, more than 70 dedicated Orleans volunteers have conducted visual herring counts each year. The electronic counter will provide 24-hour continuous counts of herring migrating up the new run, providing fisheries scientists with more accurate data for fishery management and future restoration decisions.
Over the past 11 years, data collected from the volunteer visual counts indicate a gradual upward trend in the number of returning herring. The highest visual counts and the largest MA DMF estimated run size have occurred during the past two years, partially due to minor improvements made before the entire system was replaced.
Thanks to years of volunteer stewardship efforts and a highly effective state and town partnership, the Pilgrim Lake herring run restoration project will make a significant contribution to the comeback of this important species.
Judy Scanlon is a marine biologist living in Orleans since 1960. She is the volunteer technical coordinator for the Orleans Volunteer Herring Count ProgramWater Water Everywhere is a monthly contribution of the Orleans Pond Coalition: orleandpondscoalition.org
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