It was a small step to reclaim a bit of native habitat for river herring, which once teemed in streams and rivers along the New England coast.
On Thursday, May 1, in a welcome example of intergovernmental and public-private cooperation, Massachusetts, the U.S., the town of West Tisbury, and local volunteers installed a fish ladder “over” the Mill Pond dam. It was a small step to reclaim a bit of native habitat for river herring, which once teemed in streams and rivers along the New England coast.
Herring spend most of the year in the open ocean, but each spring they migrate into fresh water to spawn. Since pre-colonial times, they have been trapped during their annual “runs” to provide food, bait, even fertilizer. Since the 1700s there have been laws on the books that govern the taking of herring, and harvesting them has long been regarded as a public right, even in a stream on private property.
As prime forage for striped bass, bluefish, tuna, and many other species, herring are an integral component in the oceanic food chain. They are also targeted at sea by purse seiners that scoop them up in huge quantities.
Fine, if their re-supply system is healthy, but it isn’t. When they’ve tried to procreate in modern times, herring and other diadromous fish have often found the paths to their spawning grounds blocked by dams, most of them built in the 1800s, but some well before that. (Diadromous fish migrate between fresh and saltwater — salmon, eels, and striped bass, for instance.) The Mill Pond dam dates to the mid 1600s.
Between overfishing and loss of habitat caused by dams, the effect on the population of river herring has been disastrous. “Species of shad and river herring once supported the largest and most important commercial and recreational fisheries along the Atlantic coast,” according to the Atlantic States Marine Fisheries Commission, which manages the two species as one.
“Commercial landings by domestic and foreign fleets peaked at 140 million pounds in 1969. Since 2000 domestic landings totaled less than four million pounds in any given year….
“In response to severe declines in population abundance, five states — Massachusetts, Rhode Island, Connecticut, Virginia, and North Carolina — have implemented moratoria on the harvest of river herring.”
An effort to remove or bypass dams has gained traction nationwide in the last few years, with notable successes in Maine — the Penobscot River in particular — and Washington state, where native salmon runs have been restored. It’s been so long since salmon migrated up New England rivers that most people aren’t even aware that the fish were once thick in those waterways.
The Mill Brook in West Tisbury is a tiny facsimile of the major rivers along the Atlantic and Pacific coasts, but it was once an open waterway used by migrants like herring, eels, and sea-run brook trout. The dam at the foot of the Mill Pond is one of several manmade obstructions along the brook, but it is the most important one in terms of extending the spawning grounds of herring and the living grounds of American eels, which spawn at sea.
West Tisbury’s attention has fallen on the Mill Brook recently because of a hot-button debate about whether or not to dredge the Mill Pond. In 2010, the West Tisbury Mill Pond Committee asked Brad Chase, a senior biologist who administers the Diadromous Fish Biology and Management Project for the Massachusetts Division of Marine Fisheries (DMF), to weigh in. He declined to take a position on dredging, but he indicated that the state would be interested in restoring the herring run.
“State law requires that dam owners provide and maintain fish passage for sea run fish,” Mr. Chase wrote in an email describing the Mill Pond project. “The Town of West Tisbury is the dam owner and responsible for fish passage. Our role is to work with towns and property owners to make sure safe and efficient passage is realized.”
Because restoring the fishway into the Mill Pond was a low priority for both the Mill Pond Committee and the town at large, the state, in the person of Mr. Chase, offered to replace a dysfunctional ladder that was installed about ten years ago by Peter D’Angelo and the late Tom Osmers, who was herring warden at the time.
It took four years for that offer to bear fruit, and it might never have done so without the persistence of Prudy Burt, a member of the West Tisbury Conservation Committee (ConCom) who has been dogged in her efforts to protect and, where possible, restore waterways throughout the town. In this case, she was acting on her own, not as a member of the ConCom.
For the installation on May 1, Mr. Chase was assisted by the DMF’s Ed Clark, who designed the ladder and prefabricated most of it, and Brian Waz of the U.S. Fish and Wildlife Service.
Johnny Hoy, West Tisbury’s herring warden, helped manhandle the main section of the ladder into position, at times scuttling into the 30-foot culvert under the Edgartown road to make adjustments.
Also on hand to lend a hand were civil engineer Kent Healy, the town-appointed caretaker of the Mill Pond, as required by the state’s Office of Dam Safety, and Ms. Burt. While Mr. Healy and Ms. Burt have been vocal in their opposition to dredging the Mill Pond, there is general agreement that the fish ladder will not be a factor in the decision to dredge or not.
The central section of the weir and pool ladder is a 30-foot-long chute in the shape of a square U with 23-inch high sidewalls rising from a 16-inch-wide “floor.” On site, with power from the recently retired police station, they constructed three-foot extensions, one for each end of the ladder.
At 8-foot intervals, wooden weirs — also called baffles — are placed across the floor of the ladder, creating pools of water deep enough for the herring to get the traction they need to jump up approximately five inches to the next pool. As they climb up the ladder from pool to pool, the fish gradually make up the two-foot drop over the spillway.
“This is the third small ladder we have installed this year,” Mr. Chase said. “I will draft an Operations and Management Plan to guide future O&M. All ladders need tuning after construction. Johnny [Hoy] has taken on this role and will figure out how to optimize the ladder entrance.”
Mr. Hoy was on the case the next day, arranging rocks in the stream to funnel fish toward the entrance to the ladder. “It’s a work in progress,” he said in an email six days after the installation. “Some tinkering and tweaking and observing has been done since it was installed, and more is needed. We will get it going. There was a herring and an eel in it yesterday!”
This year’s herring run was winding down by the time the ladder was installed, so its impact won’t be known until next spring, at the earliest. Its long-term success depends on many variables, but it would never have had a chance without the persistence and dedication of a few individuals determined to make a small local contribution to a global problem.
“I think Prudy Burt is behind most good ideas concerning water in West Tisbury, and this one was no exception,” Mr. Hoy said. “We had the support of Kent Healy throughout the project, both for advice and for coordinating the opening of Tisbury Great Pond to the Atlantic to let the [herring] in at the appropriate time. The crew from the state were three of the hardest working, most pleasant guys I’ve had the good fortune to work with in a long time.”
The feeling was mutual. “It was super to work with everyone on this project,” Mr. Chase wrote. “Working with Ed, Brian, and Johnny in that culvert will be a highlight of this year for me. It beats working in my cube any day. I am really hoping to hear the news of herring passing into the pond any day.” It sounded like he was expecting it, too.
Whit Griswold is a member of the West Tisbury conservation commission.