Prehistoric wonder

Extensive fishing contributed to the decline of the shortnose sturgeon. Can it survive?

WESTMINSTER — Recent research is warning that the rapid loss of wildlife in recent decades shows the sixth mass extinction over the past 400 million years in Earth's history is underway.

In the face of this warning, it is important to note that the Connecticut River watershed is the home range for five threatened or endangered species that rely on healthy clean water: the dwarf Wedgemussel, the puritan tiger beetle, the Northeastern bulrush, Jesup's milk-vetch, and the shortnose sturgeon.

As of now, there are healthy - albeit small - populations of each of these species in our watershed.

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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 1 inch wide and deep. The shells are 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 the beetles are still here and of concern in the Federal Energy Regulatory Commission's current relicensing of dams on the Connecticut River.

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.

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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 its head, an atypical arrangement.

Given its prehistoric appearance, it is easy to imagine fish of this species coexisting with dinosaurs - and 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, and poorly developed eyes, mouth, and fins.

They can barely swim, so they are not a free-swimming fish; hence, they actively seek cover under any available material, like trees, aquatic plants, and cobblestones. Eventually, the fish will reach 4 feet in length and weigh in at 40 pounds or more.

More than a century of extensive fishing contributed to the decline of shortnose sturgeon populations all along the East Coast of the United States. 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 species in the Connecticut River.

Access to spawning habitat, and the limited exchange between the fish below Holyoke and Turners Falls reach, hindered the sturgeon's 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's 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.

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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 fish in 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 U.S. Geological Survey's Conte Anadromous Research Center in Turners Falls offers guidance to fishery agencies on how best to protect spawning locations and to mitigate the effects of hydropower operations - especially important during the current relicensing of Connecticut River hydropower operations at Northfield Mountain and Turners Falls Dam.

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!

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