The waters of Ligonee Brook saw a once-rare rush of small fish down its shallow, winding reaches last week, as a year-class of alewives dashed out of Long Pond for the tidal waters where they will grow to adulthood.
For the better part of the week, which coincided with the October full moon, hundreds of the tiny young-of-the-year fish could be seen at various points along the brook’s route, scurrying through the curves, over the shallow spots and under the snags of broken tree branches, catching leaves as they drifted with the steady flow of the brook in this exceptionally high-water year.
Alewives are a species of herring, one of several species of river herring that, like salmon and striped bass, live their adult lives at sea but charge up even impossibly shallow trickles of freshwater to lay their eggs in freshwater streams and ponds.
It was not even a decade ago when the adult progenitors of this fall’s escapees would not have been able to make it up the chronically clogged brook to Long Pond to spawn.
The pond’s obstacles have slowly been chipped away. First, the Friends of the Long Pond Greenbelt spearheaded a major clearing-out of the creek bed and an effort to raise awareness of the numerous blockades in the creek.
Then came Eagle Scout Max Yardley and his project to remove a culvert from the former railroad bed that once connected Sag Harbor to Bridgehampton by train.
This year, Southampton Town Trustee Bruce Stafford led another major clearing of fallen branches and tree trunks, not to mention human detritus, from the brook’s path. A fallen tree branch can quickly collect leaves and other sticks that will gradually choke off the passageway for fish.
“The culvert under the [Bridgehampton-Sag Harbor Turnpike] is still a problem that we’re hoping the county will address soon,” said Dai Dayton, of the Friends of the Long Pond Greenbelt, who was one of the leaders of the original effort to clear out the run of Ligonee Brook in 2010.
For a variety of meteorological and hydrological reasons, the water levels in Long Pond — and, therefore, in the brook that babbles its way to the back-most headwaters of Sag Harbor Cove — have been very high. In dry years, the brook can be effectively dry, or just a moist trail that young eels, which also are born in the pond, can make their way through but which traps either adult or juvenile alewives.
Ms. Dayton noted that an ephemeral lens pond known as Slade Pond, just off the Bridgehampton-Sag Harbor Turnpike, was full this year for the first time in several years.
“This year was pretty much as high as it gets,” she said. “It’s nice to see. It will get like this and then it will maintain for a few years but gradually it will slowly drop down again. Hopefully, we will get some good runs while it’s like this. The eels should be moving now, too.”