River Currents: Combating habitat degradation along the Connecticut River
In the face of this warning of the sixth great extinction over the past 400 million years of earth's history, it is important to note that the Connecticut River watershed is the home range for five different threatened or endangered species that rely on healthy clean water. The species are the Dwarf Wedgemussel, Puritan tiger beetle, Northeastern bulrush, Jessup's Milk vetch, and the shortnose sturgeon. As of now there are healthy albeit small populations of each of these species in our watershed.
The Dwarf Wedgemussel lives in sandy or gravel bottoms. The highest concentration of the mussels is in the Connecticut River above Massachusetts. The mussel's shell size rarely exceeds 1.5 inches in length and one inch wide and deep. The shells are colored brown or yellowish- olive, with reddish brown or greenish rays in young specimens.
The Puritan tiger beetle is an inhabitant of sandy beaches above the water line. The beetle population has declined along the Connecticut River due to habitat disturbance from dam construction and operation, riverbank destabilization, and human recreational activities, but they are still here and of concern in the Federal Energy Regulatory Commission relicensing underway right now.
The Northeastern bulrush is a leafy, tufted, perennial sedge that ranges from Maryland to New England and is found growing on the edges of seasonal pools, wet depressions, beaver ponds, or wetlands that have variable water levels. You can find the bulrush along the Connecticut River and tributaries where the water level fluctuates due in part to hydro generation.
Jesup's Milk vetch grows up to 24 inches tall and lives on the rocky outcrops in only three known locations in New Hampshire and Vermont along the river. Jesup's milk vetch is in the legume family and emerges after the winter ice and spring floods have receded. It grows from a taproot that serves to stabilize the plant during high water events and stores vital nutrients.
The star of this story though is the shortnose sturgeon (Acipenser brevirostrum). It is a primitive looking fish with five rows of bony plates covering its body and a mouth found on the underside of their head, an atypical arrangement. Given their prehistoric appearance it is easy to imagine them coexisting with dinosaurs as they did. Shortnose sturgeons do live in the sea but our populations live mostly in the river or its estuary.
Newly hatched shortnose sturgeons are blackish, half an inch long, and resemble tadpoles with a large yolk sac, poorly developed eyes, mouth and fins, and can barely swim so they are not a free-swimming fish and hence they actively seek cover under any available material like trees, aquatic plants, and cobble stones. Eventually the fish will reach 4 feet in length and weigh in at 40-plus pounds.
More than a century of extensive fishing contributed to the decline of shortnose sturgeon populations all along the east coast of the U.S. People thought the Connecticut River shortnose sturgeon were extirpated until an isolated population was documented trapped between the Turners Falls and Holyoke Dams in Massachusetts.
The Holyoke Dam, built in 1869 is a significant barrier between the sturgeon that live upstream and those below the dam. Unfortunately, the primary spawning areas for shortnose sturgeon lie upstream of Holyoke in the Turners Falls reach of the river. Fishery experts estimate that the upriver group numbers up to 700 adult fish. Due to the natural falls formation, Turners Falls is thought to be the natural upstream extent of the range of shortnose sturgeon in the Connecticut River.
Access to spawning habitat and the limited exchange between the fish below Holyoke and Turners Falls reach hindered recovery. In the 1980s, the Holyoke Dam installed a fish lift that let some fish move up and downstream. We are still trying to improve the sturgeon ability to find the fish lift when trying to move upstream and avoiding the turbines when they pass through the power generating units as they head downstream.
After a 2000 relicensing settlement agreement, the Holyoke dam owner began making major changes to the dam and associated canals to improve the ability of shortnose sturgeon to pass both up and downstream. Once the complex task is complete (and yes, it is still underway 17 years later), the lower river population will be able to complete their spawning run to Turners Falls and upstream fish can migrate to food rich foraging areas in the estuary with Long Island Sound.
Habitat degradation resulting from dams, bridge construction, channel dredging, pollutant discharges, incidental capture in commercial fisheries and poor overall water quality are continued threats to sturgeon. Research at the Conte Anadromous Research facility in Turners Falls offers guidance to fishery agencies on how best to protect spawning locations, mitigate the effects of hydropower operations, especially important during the current relicensing of Connecticut River hydropower operations at Northfield Mountain and Turners Falls Dams.
There is hope that this wonder of a prehistoric fish will recover its full habitat and its numbers but hydroelectric facilities owners need to step up and help in this restoration effort and provide full protection for the quintet of remarkable threatened and endangered species in our river. Let's keep the music playing!
Representative David L. Deen, D-Westminster, is Chair of the Natural Resources, Fish and Wildlife Committee in the Vermont House and Honorary trustee of the Connecticut River Conservancy. He can be contacted at firstname.lastname@example.org. The opinions expressed by columnists do not necessarily reflect the views of the Brattleboro Reformer.
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