By Mike Bottini
Sagg Pond is the southernmost link in the Long Pond Greenbelt’s north-south trending chain of kettlehole ponds and vernal pools. Unlike the other “chain links” spanning the seven miles between the Atlantic Ocean and Sag Harbor, most of Sagg Pond’s shoreline is privately-owned and it is best visited using a shallow draft paddle craft. And unlike the other greenbelt ponds, Sagg is neither fresh nor is it tidal in the strict sense of each term.
This pond is one of our particularly interesting and unusual waterbodies that defies an accurate label or category. Among the descriptive terms used for Sagg Pond are salt pond, saline pond, brackish pond and coastal lagoon. In the Sagg Pond chapter of my East End paddling guide, I used the former – salt pond – but one could argue that the term is the least accurate of the lot.
As with all the greenbelt’s ponds, Sagg Pond’s main source of freshwater is groundwater, which is constantly seeping into the 150-acre pond along its entire shoreline. A not insignificant freshwater surface flow enters the pond’s north end by way of Solomon’s Creek, draining Sagg Swamp and empting into the pond at the bridge – known as White Walls – on Sagaponack Road. But since the swamp and creek are also groundwater fed, Sagg Pond’s water quality is heavily dependent on protecting the groundwater quality beneath the surrounding land area from as far away as 1.5 miles, and includes farmland and residential estates.
The pond’s northern section has a classic freshwater appearance. The shoreline vegetation there is a mix of black pepperidge, or tupelo, swamp maple and willow. It is rare not to hear the noisy rattle-call of the belted kingfisher, and glimpse the striking, crested, blue and white bird darting from its hidden perch, when paddling through this stretch of the pond. Be sure to search the overhanging limbs for roosting piscivores: double-crested cormorants and several species of herons and egrets. I’ve also glimpsed Sagg Swamp’s resident great-horned owl perched in this corner of the pond.
Paddling south, the swamp trees are soon left behind. The pond sits squarely amidst the best agricultural soils in the world and, since the 1600s, both shorelines were plowed and worked as farmland. The original forest that covered these deep, rich soils has been gone for so long that we are unsure of its exact composition. A few patches of cattails, three-square rush and the freshwater species of cordgrass (Spartina pectinata) can be found, as well as the conspicuous flowers of mallow. All provide excellent food resources for waterfowl, shorebirds and muskrats that inhabit the pond.
By the time the Bridge Lane bridge comes into view, a large grass species – phragmites – dominates both sides of the pond’s shoreline, towering six to ten feet above my canoe and growing so thick that it obscures any view of the adjacent farm fields. Its long, thin, brittle stem is topped by a beautiful plume-like inflorescence, not an unattractive sight, particularly when set in motion by a light ocean breeze and the late afternoon sunlight. It’s no wonder that some are dismayed to learn that this plant is the bane of many wetland ecologists who have devoted their careers to eradicating it.
A few songbirds have adapted to utilizing the dense phragmites stands as nighttime roosts. Hugging the shoreline with my canoe at dusk, huge flocks of red-winged blackbirds nervously reposition themselves as I pass close by, making a noise that resembles a gust of wind through the reeds.
About six years ago I was lucky enough to get a good look at possibly the most rare year-round resident of Sagg Pond near the Bridge Lane launch site. No, not Peter Mattheisson, but a pair of immature mink! Although the entire Long Pond Greenbelt has excellent mink habitat, Sagg Pond is the only place I’ve seen them or their sign. Mink are in the mustelid or weasel family, and they share many behavior traits with other species in this group, although they are generalists and do not excel in any one hunting technique. They can climb trees to predate on bird nests, but not as well as the pine martin; they are adept at hunting mice and voles, but not as well as the long-tailed weasel, and they can take to the water to catch fish, but not nearly as well as the river otter.
Most summers, at least one person can be found with a chicken neck on a string in one hand and a long-handled net in the other, trying their luck for blue crabs at Bridge Lane. This technique requires a good feel for pulling the crabs within netting reach, and is also done from the beach at the south end of the pond.
Fishermen also line up here to catch whitefish and white perch. Eels are also harvested from the pond, using eel pots, similar to a lobster trap. The water here is brackish, becoming more saline as you get closer to the sand beach that forms a leaky dike separating the pond from the ocean. The dike only leaks in one direction, southward from pond to ocean because of the hydraulic head created by the pond’s elevated surface: usually 4-6 feet above the mean level of the ocean. Since ocean water does not flow through the beach sand and into the pond, exactly how does saltwater get in?
The one hundred yard width of the sandy beach is breached – naturally via storms and ocean overwash, or rising pond water levels and overflow, or artificially via a backhoe – an event known locally as a “let.” Lets take place at the “gut,” the unvegetated, flat, narrowest section of beach between the ocean and pond. The fact that lets occur several times per year prevents the development of beach vegetation and dunes in the vicinity of the gut.
The timespan during which the pond is open to the ocean varies considerably with each let. Some lets remain open for less than a day before longshore currents reseal the breach. Others have remained open for over a month, at times prompting the Trustees charged with managing the pond to request a backhoe be brought back to the site, this time to rebuild the sandy dike.
A let serves several purposes. Some are timed to allow migratory fish, for example alewives, access to the pond to spawn in spring. A fall let allows the juveniles out, and access to their overwintering grounds far offshore. Heavy rains and rising pond levels may prompt a let to reduce local flooding.
Lets don’t just lower the pond level and allow fish to come and go. They also ‘freshen’ the pond by increasing salinity levels. The ocean high tide reverses the flow of water at the gut, pushing a small portion of the highly saline Atlantic into the pond, creating ideal salinities for estuarine species: blue crabs, mummichogs, silversides, killifish, sheephead’s minnows and others.
These prolific species attract the flying piscivores. I’ve counted as many as eight osprey circling over the south end of the pond when the alewives are running. Flocks of cormorants swim and dive in formation. Least and common terns hover close to the surface, diving beak-first. Black skimmers arrive near dusk, flying inches above the water, with their odd beaks barely touching the pond. Egrets and herons stalk in the shallows on the pond’s edge. With easy access to the ocean intertidal zone, and the rich food resources of the pond, the beach provides excellent habitat for nesting terns and plovers.
When the gut is open to the ocean, the pond mirrors the ocean tides. With low tide, large areas of sandy shoals and mudflats are exposed, attracting shorebirds that probe in search of worms and small mollusks. The incoming tide will send pulses of seawater through the narrow gut and into the pond, filling it ever so slightly. This place, where the ocean meets the pond, is fascinating and watching all the water in motion can be mesmerizing.