Compiled by Tom Lake, Hudson River Estuary Program Consulting Naturalist
More than half of our Almanac entries this week (58%) feature Hudson River natural history education for students from elementary school-age to college. While the goal of the Almanac is to share adventures, the focus has always been on education.
Highlight of the Week
7/29 – Manhattan, HRM 2: In early afternoon, a member of the construction crew restoring pilings under the Hudson River Park’s Pier 40 brought a large oyster (Crassostrea virginica) to The River Project. They had found the oyster – 220 millimeters-long (mm) and weighing 23.3 oz. (1.46 pounds) – living on one of the pilings. At 8.66 inches-long, this was by far the largest oyster recorded in the estuary in modern times, exceeding one found on Hudson River Park’s Pier 25 during summer 2017 (185 mm or 7.3 inches).
This giant oyster is alive and well at Pier 40 for reasons far more complex than simply saying, “the river is getting cleaner.” We measure the river's water quality in terms of how we interact with it, i.e. swimming and eating fish. Oysters and many other marine organisms have a different ecological measure. This oyster likely found the perfect niche on a piling that, in addition to being perfect, may have also been unique. (Photo of giant oyster at Pier 40, Manhattan courtesy of Toland Kister)
[A discussion of giant oysters in the Hudson River must begin 32 miles upriver and 5,000 years ago, with archaeologist Louis Brennan’s excavation of the Kettle Rock site at the north end of Croton Point (1960). Brennan discovered shell middens (ancient refuse heaps) of large oysters – eight-inches-long on average – which he called G.O., or Giant Oysters. Oyster shells found chronologically above and below this strata or horizon were five-inches-long or less. This G.O. strata – approximately six-inches-thick – radiocarbon dated to c. 5,387 years old. Brennan believes this phenomenon occurred during a time of significant sea level fluctuations in the estuary as well as the accompanying salinity regime that may have created optimum conditions for oyster growth (Brennan 1962). The Indians who shucked these oysters were hunter-gatherers ancestral to the Lenape people who met Henry Hudson in 1609. Tom Lake]
[Note: one inch = 25.4 millimeters (mm)]
- Toland Kister