A Pond Under Pressure
By Larry Penny
(03/14/2007) At 173 acres, Fort Pond in Montauk is the second largest freshwater lake on Long Island behind Lake Ronkonkoma, 240 acres large. Up until 1925, Lake Montauk, nearly a thousand acres, was the largest lake, but it has remained completely tidal since that time.
East Hampton Star Archives
Fort Pond, seen here at the beginning of the 20th century, is the second largest freshwater lake on Long Island.
In pre-settler times, and perhaps afterward for a short period, both of Montauk’s two largest water bodies were opened periodically to the sea, Fort Pond to Fort Pond Bay, Lake Montauk to Block Island Sound. They were also opened by rising waters from rain runoff and coastal overwash, as Oyster Pond to their east still is from time to time. The 1838 United States Coast Survey map of Montauk clearly shows intermittent overflow dreens at their north ends.
Fort Pond is a gem, not only for fish and fishermen, but also for a host of wildlife. But nowadays, as with Las Vegas, everything that goes there, stays there.
The jetties constructed on either side of Lake Montauk’s inlet permanently opened it to the sea. The Flaggy Hole railroad line through Hither Hills linking East Hampton to Montauk just north of Fort Pond, constructed just prior to the end of the 19th century, separated Fort Pond from Fort Pond Bay, and the pond has remained fresh ever since.
Fort Pond and Lake Montauk were old meltwater channels (vis-a-vis Georgica, Hook, and Sagaponack Ponds), caused by the outflow of glacial streams eroding the morainal lands on their sides about 15,000 years ago. Lake Ronkonkoma, which is circular, is more of a kettlehole pond, isolated as it is from coastal waters by its inland location.
Fort Pond’s surface reflects the top of the water table, which rises and falls depending upon the degree of precipitation from year to year. The precipitation recharges the upper glacial aquifer (of which the pond is a part), but also runs off into the pond from the adjoining highlands and from its peripheral roads.
Since its primary watershed is several hundred acres in extent, runoff from, say, a two-inch rain can elevate the pond two to three inches overnight. On a windless day the pond’s surface in its central part is slightly higher than to the north and south. Consequently, south of this point, water flows out underground to the Atlantic Ocean, and north of it to Fort Pond Bay.
Tidal differences between the ocean and the bay tend to influence the exact position of this water “divide” at any single moment. The last time the pond was connected to the seas was in late summer of 1954. Hurricane Carol caused the Atlantic Ocean to sweep through downtown Montauk and spill into it.
Fort Pond averages about 12 feet in depth and is more than 25 feet deep at its deepest point just north and east of its center. Thus it is about twice as deep as Lake Montauk and about half as deep as Lake Ronkonkoma.
As seen with the naked eye and measured on a United States Geological Survey water level gauge installed in 2002, the pond stands at a record-high level. The small wooded island, which was shown on the earliest maps available, is completely submerged save for the tupelo trees and other vegetation, which cannot tolerate the two-plus years they have been underwater.
In 1890, before the advent of the railroad, such a high water level would have forced the pond to overrun its banks and let itself out to the bay. Obviously, such relief is no longer possible.
Fort Pond hasn’t been flushed out since the railroad tracks separated it from Fort Pond Bay at the end of the 19th century.
Fort Pond is a bountiful aquatic habitat, chock full of fish, most of them from early-on stockings by various entities or individuals, but lately by the State Department of Environmental Conservation. Long Island, because of its relatively short life geologically speaking, has been isolated from the freshwater fish fauna that populates the rest of the state. Such fish species belong to the Great Lakes, Hudson River, Delaware River, and Susquehanna drainages, and thus were able to travel from south to north up rivers as the ice sheet retreated 25,000 to 12,000 years ago.
It wasn’t as easy reaching Long Island from the southern refugia, however. Long Island’s native freshwater fish fauna consists of yellow perch, pumpkinseed sunfish, banded sunfish, pirate perch, brook trout, redfin and chain pickerels, and several small baitfish, including the banded killifish, mudminnow, golden and bridled shiner, swamp and tessellated darters, and three-spined stickleback.
Fish species that can tolerate saltwater and thus move easily along Long Island coasts, such as the alewife, smelt, striped bass, American eel, tidewater silverside (or “white bait”), and nine-spine stickleback, are part of the native fish fauna found in Long Island’s fresh waters. Of these, Fort Pond has yellow perch, chain pickerel, banded killifish, pumpkinseed, white perch, and American eel.
Much later on, largemouth bass, smallmouth bass, bluegill, and carp (native to Eurasia) managed to find their way into the pond. In the latter part of the 20th century, a striped bass-white perch hybrid was stocked by the Department of Environmental Conservation and did well for a time, and within the last eight years walleye pike as fingerlings were added by the D.E.C.
This last species, native to central and northeastern North America’s lakes and ponds, was first added to Lake Ronkonkoma, and a few years later to Fort Pond, in both cases in the form of hatchery-raised fingerlings. They were added not only to provide a very popular freshwater game fish to the existing stocks, but as an experiment to try to overcome the “stunting” problem that is ubiquitous in America’s lakes, ponds, and streams.
It seems that the food chain is eaten down to its base — the same thing is happening in the world’s oceans — such that the game fish become smaller and smaller. The zooplankton crop, the small aquatic invertebrates that the young game fish feed on, are overgrazed. The game fish adults, in turn, predate and deplete their young. They don’t get enough to eat.
The walleyes are supposed to counter this by feeding on the baitfish and the fingerling game fish, in particular the juvenile perch, thus relieving the predatory pressure on the zooplankton, increasing their abundance, and rebuilding the food chain from bottom to top, trying to achieve the pre-stunting dynamic balance that produces larger fish.
At the same time, the increasing zooplankton population is able to eat more of the phytoplankton, preventing “blooms,” which burn up the dissolved oxygen at night and cause several other problems. It’s an interesting experiment and, according to Charles Guthrie, who heads the D.E.C.’s freshwater fishery program on Long Island, seems to be working.
In 2004 the number of yellow perch caught by gill netting and electrofishing in Fort Pond by Mr. Guthrie and his staff decreased by more than half, while the number of largemouth bass increased slightly when compared to the figures for the 2001 sampling. The maximum walleye size and weight reached in 2004 were 22.5 inches and 4.24 pounds, while in 2001’s sampling they were 19.1 inches and 2.52 pounds. After about 20 inches, the weight increases a pound for every inch in length added.
The longest largemouth bass caught for both 2001 and 2004 samplings was 19.9 inches and 5 pounds. The largemouth bass is a deeper-bodied fish than the walleye, which is elongated.
The 2004 sampling, however, did not produce a single walleye less than a foot long, while the 2001 sampling produced two different size groups below that length, about 9 and 4.5 inches respectively. In other words, the two batches of walleye fingerlings stocked a year apart had grown up to more than 12 inches in length by 2004, but there were no new young coming along, thus no breeding by the stocked fish and no recruitment.
A sampling to take place this year will determine whether or not walleyes will breed in Fort Pond. Since Fort Pond by some measurements is the second most popular fishing pond on Long Island, and because largemouth and smallmouth bass are such valued game fish, most likely many bass larger than those sampled by the D.E.C. were taken by rod and reel.
White perch were the most common fish sampled, amounting to 973 and 1,272 individuals in 2001 and 2004, about five times as many as the next most populous fish, the bluegill. One of the objects of the walleye introduction was to reduce the number of yellow perch, which were prime predators of largemouth and smallmouth bass young. Their numbers dropped in the collection by a factor of five from 109 in 2001 to 23 in 2004. The walleyes may be limiting the number of perch.
Fort Pond is a gem, not only for fish and fishermen, but also for a host of wildlife, including breeding Canada geese and mallards, overwintering waterfowl, muskrats, mink (Jimmy Grimes found a roadkill adult on Industrial Road north of the pond in December), turtles, frogs, freshwater mussels, and a host of other species.
On the other hand, it has been lucky so far not to have suffered a fish kill. It is dumped into through some seven large culverts, which shunt runoff and the pollutants it contains from three of its perimeter roads, Montauk Highway to the south, Second House Road to the west, and Edgemere Road to the east.
It also receives sheet runoff from steeply sloped residential areas on the east and west, as well as commercial sites on the south. A Long Island Power Authority plant with voluminous underground fuel oil tanks buried in groundwater on the northwest shore, and several commercial ventures along Industrial Road, including an East Hampton Town highway barn, all have the potential to pollute.
On the east and west sides, in addition to single-family residences, there are multiple-occupancy dwellings, which generate a large amount of septic flow containing nitrogenous wastes, as well as other nutrients, chemical cleaning agents, microbes, and so on, entering the pond’s waters from below. On the south, in addition to several businesses, is a popular soccer field, which was designed to pitch toward the ocean but actually was constructed to pitch toward the pond.
More than a century ago the pond could be partially flushed out by opening it to the sea in the manner that Georgica Pond is flushed out at least twice a year to the ocean. Nowadays, as with Las Vegas, everything that goes there, stays there. The East Hampton Town Natural Resources Department offered the town a set of recommendations in a 1997 Watershed and Aquatic Habitat Study and Enhancement Plan, but thus far little has been done to mitigate its concerns.
If Fort Pond follows in the path of Lake Ronkonkoma, which was built much earlier and has serious pollution problems, watch out. Instead of the second-largest lake on Long Island, it will be destined to become the second most polluted lake on Long Island. It could be just around the corner.
Questions and comments can be sent to Mr. Penny at [email protected]