High Noon on the Peconic River

June 13, 2011 – 12:00 p.m.

The Explorer Tour Boat sets out daily on the Peconic River, come rain or high water.  In fact, today at noon we were approaching high tide with air temperature 70° F, partly cloudy skies, and 1-3 mph northwest wind.  Along the river, we sighted a number of Purple Martins, Red-winged Blackbirds, Double Crested Cormorants, Mute Swans, Herring Gulls and Blackback Gulls, Great Egrets, Canada Geese with goslings, a solitary muskrat and a 3 ft. Northern Water Snake cruising along the grassy banks.  At the mouth of the river near the Rte. 105 bridge, a pair of Osprey perched on the edge of their nest in the center of Colonel Island.  Three more Osprey nests are active along this stretch of the river.

Heading across Flanders Bay toward Hubbard County Park, there was very little boat traffic, a light breeze and small glassy wavelets.  At Birch Beach, we disembarked and came upon a pair of Horseshoe Crabs mating onshore in a still-rising tide.  The female was three times larger than the male, each robust and encrusted with barnacles and slipper snails.  Among depressions in the wet sandy intertidal zone, we discovered a substantial number of developing Horseshoe Crab eggs, small transparent spheres with pale turquoise larvae swimming and tumbling in circular paths inside the spherical membrane.  The embryonic form appeared between 10 and 12 days old, ready to emerge in another two days.

A Great Egret and an Oystercatcher skimmed the surface of the outflow of Birch Creek.  A Dowitcher probed the shallows.  Beach Goldenrod, Beach Rocket and Spartina patens were scattered along the high beach.  Spartina alterniflora has grown about 18 inches high; numerous small schools of juvenile Atlantic silversides and larger striped killifish skirted the shoreline and swam throughout the flooded salt marsh.  Our seine net picked up a few of the baitfish, small lion’s mane jellies, a one year-old bay scallop, grass shrimp – females with clusters of eggs against their abdomens – and long-clawed hermit crabs, some with fuzzy pale pink “snail fur” – colonial hydroids – adorning their borrowed mud snail shells.  Live mud snails patrolled the bay bottom, assembling wherever a dead crab or scrap of animal tissue lay.

At our crab trap in the middle of Flanders Bay, we used a YSI meter to record the following readings:

     Surface – water temp – 21.9° C, salinity – 25.5 ppt and DO – 6.12 mg/L

     Bottom – water temp – 21.7° C, salinity – 26 ppt and DO – 6.4 mg/L

Near Colonel Island at the mouth of the Peconic River:

     Surface – water temp – 23° C, salinity – 12.2 ppt and DO 5.97 mg/L

     Bottom – water temp – 21.4° C, salinity – 24.8 ppt and DO – 3.45 mg/L

At the dock, behind Main Street in Riverhead:

     Surface – water temp – 22.6° C, salinity – 13.2 ppt and DO – 3.26 mg/L

     Bottom – water temp – 22.2° C, salinity – 23.3 ppt and DO – 0.72 mg/L

The Peconic Estuary is an Estuary of National Significance, one of 28 in our country granted that distinction by the federal government.  It is a dynamic, powerful ecosystem, deserving of careful monitoring and preservation.  We hope to offer a small contribution of our observations over the next twelve weeks to inspire people to visit and treasure this great natural resource and to assist our communities of scientists and conservationists in their important work.

Submitted by Ann Haskell, Marine Educator, Blue Ocean Institute

The Blackbacked Gull is the largest sea gull.