Darien Land Trust Prepares a Feast

The Darien Land Trust is preparing a giant banquet; but unlike even the most ambitious Thanksgiving Day cook, the Land Trust will be preparing for a few years. When the feast is ready, it is sure to lure great blue herons, osprey and long-legged egrets to soar in record numbers over the Noroton River waterway leading to Holly Pond and the sea beyond.

The centerpiece of the banquet table: a matured river herring.

Also known as alewives and blueback herring, these fish, while generally not palatable to humans, serve as the "field mice of the sea," so called because everything else eats them. They are potentially the single largest food source for birds, other fish and mammals that live along the river. A single adult female lays about 100,000 eggs. Of these, only 1,000 will survive to become two-inch-long juveniles able to migrate down the river.

"Nesting ospreys have to have healthy runs of alewives to prosper," said Steve Gephard, a supervising biologist with the state Department of Environmental Protection.

The surviving river herring will be returning from several years at sea to spawn at Olson Lake. Earlier this year, the DLT's Denis Frelinghuysen, together with the DEP, stocked the lake with the herrings’ mothers; soon thereafter, they hatched. The DLT owns the surrounding Olson Woods, and plans to re-stock next spring.

The DEP captured the two hundred gravid, or pregnant, alewives from the wild at Bride Brook in East Lyme, where they are abundant, for shipment to Olson Lake.

The anadromous fish—which breed and spawn in freshwater but spend the rest of their lives in salt water—were once plentiful at Olson Lake and in the Noroton River, which flows through it. But the population plummeted to near zero when the Department of Transportation designed and installed a nondescript cement culvert to channel the Noroton River beneath an overpass during construction of I-95 through Darien in the 1950s.

Whether by DOT design or stream-bed erosion (it was so long ago it no longer matters which, said Gephard), the top of the culvert is 12 inches above the stream surface except during times of flood. It is a barrier to river herring whose genetic code directs them to swim upstream to the place of their birth to breed and spawn but whose physical limitations (they do not jump like salmon) prevent the journey.

"The 30-foot cement ledge disrupts the entire ecosystem," Frelinghuysen said.

Fixing the problem is no small task.

Riverside properties are at risk of seasonal flooding if the stream-bed is raised too high to reach the top of the culvert. Other conservation groups are applying for funding to study the site; later, engineered plans will be submitted to state, local and federal agencies. In the meantime, the DLT is taking corrective measures to enable the alewives to return upstream, a fish ladder among them.

All of this will all take several years to accomplish.

The feast at Olson Lake will have to wait.

On the other hand, the timing is exquisite. Since the 2009 hatchlings will not begin to return to their spawning grounds for several years, when they have reached reproductive maturity, the culvert should be fixed by the time they arrive.

"With a little bit of luck, they will be up and over in 2012," Gephard said.

(It will be a bittersweet time for the young breeders: their mothers are expected to return throughout their lifetimes to Bride Brook in East Lyme, where they were spawned, to breed again.)

The DLT’s participation in the river herring run fits neatly into its overriding mission of enhancing the varied ecosystems of the Noroton River/Holly Pond waterway.

With its near-seven acres of parcels, the DLT is the largest property owner on Holly Pond, and it has been applying tender loving care in full measure to attract wildlife and enhance biological diversity.

Recently, ospreys have been nesting on the Darien shoreline after years of absence, even without alewife stocking at Olson Lake. Snowy egrets, once a threatened species, have been spotted in large numbers at Gorham’s Pond.

"You might conclude they’re a common bird unless you were aware they were decimated by DDT in the 1970s," said Frelinghuysen

Smart stewardship of its critical salt marsh properties and development of a native wildflower meadow just upland are just two examples of the trust’s many initiatives to conserve and protect the Holly Pond shoreline and become, says the DLT, “a positive force for nature.”

The Darien Land Trust will hold their annual meeting on Sunday, Nov. 15 at 5 p.m. at the Wee Burn Country Club. The evening, entitled “Becoming a Positive Force For Nature,” will include a discussion on the DLT’s bird habitat conservation efforts and the screening of a short film, The State of the Birds. An art show and reception will follow. All are welcome.