Shocked fish tell scientists tales in Stillwater.
Pumpkinseed - 62. Long-nose - 104. Tasellated - 88.
Such was the esoteric narrative of local fisheries technicians Derek McDermott and Bennet Leon, dictating fish lengths in millimeters to the project leader, Dr. Caleb Slater. We were in waders and hip boots, electro-shocking sections of the Stillwater River feeding into Wachusett Reservoir to determine the health of numerous species that live there, particularly landlocked salmon.
McDermott incredulously commented on the river level being lower than he had ever seen it in his life. Fortunately, the Stillwater is fed primarily by cold, clean-filtered groundwater that comes up through West Boylston's invaluable gravel substrate. Despite warm air temperatures, the river was running about 50 degrees - comfortable for trout and salmon.
McDermott carefully carried a backpack with a 24-volt, battery-powered Electro Fisher. The instrument can be juiced up or down, depending on a specific water's conductivity. Basically, the cleaner the water, the higher the voltage needed. The previous week, the research team needed 600 volts to shock our pristine western salmon streams.
The Stillwater, with significantly more nitrates and phosphates, required only 300 volts. As we waded upstream, McDermott submerged an extension pole, looking much like a metal detector. Stunned fish immediately floated to the surface to be netted and placed in containers for later identification, measuring and release.
Wearing rubber wading gear, we were immune to the shocks occurring all around us. Our sampling areas were 100 meters of river. The first stretch, not far upstream of the reservoir, yielded more than 300 largemouth bass, pumpkinseeds, tasselated darters, long-nosed dace, white suckers, crayfish, frogs, redfin pickerel, black-nosed dace, yellow bullheads, brook trout and landlocked salmon.
It was impressive to see the team expertly identify each fish while still submerged. Few veteran fishermen can differentiate some of these species, especially the minnow-shiner complex. The little yellow bullheads can easily be confused with brown bullheads, too. To distinguish them, look at their barbels. They have a large, prominent, lateral pair that look like a mustache, and less prominent, beard-like ones under their chin. If the latter are yellow, you've got a yellow bullhead; if they're brown, your fish is a brown bullhead.
McDermott and Leon periodically carried buckets of fish down to a live well, weighted down in the river with a big rock. All samples would wait there for us until we were through collecting from the entire sample stretch.
Much can be learned from this labor-intensive research. Most obviously, one can determine the makeup of the local fish population. Its biodiversity is fairly small, a result of glaciers destroying many species here 10,000 years ago. Whatever native species exist today have returned in the interim. Most of the fish, though, are introduced species, like our largemouth bass, smallmouths and blue gills.
By measuring and graphing each species, one can see size-spikes of year-classes. For example, the graph of 1-year-old brook trout will clump around 2 inches. Two-year-old brook trout will cluster around 4 inches. First-year salmon average about 3 inches; 2-year-olds average about 5 or 6 inches. Taking accurate counts and length measurements can help reveal how a particular age class is doing. If the average population sample or size of an age class is smaller in subsequent years, we know something is wrong. Slater has been doing the same stretches of the same waters for about 20 years. His long-term analysis is invaluable in revealing population trends.
Most native brook trout survive only three years, attaining a maximum size of about 6 inches in our little streams. They get hammered by predation from mink, otters, herons, kingfishers, and winter ice, which kills many of them, as well as an estimated half of our young salmon.
Our target landlocked salmon are self-sustaining, though, despite all the hazards they face, with no stocking of them in the watershed. Their original populations may well have arrived in Wachusett from the aqueduct that connects it to Quabbin. Lakers may have come in the same way. They're not stocked either.
Landlocked salmon spend the first two years of life in the river, growing to about 6 inches before leaving to mature in the reservoir. Once mature, they'll leave the reservoir to spawn upstream in the Stillwater usually in October and November, as soon as the first substantial rains cause the river to rise.
Hopefully, one day we can remove the dam from the Quinapoxet River in Oakdale. That single act would triple the suitable habitat for landlocked salmon in the watershed.
Mark Blazis can be reached by e-mail at firstname.lastname@example.org
Tomorrow - Falconry season for ducks and coots opens through Feb. 10.
Tomorrow - Sea duck season (scoters, eiders, and long-tailed ducks) opens through Jan. 29.
Sunday - Safari 3D Archery League Tournament. Hamilton Rod & Gun Club, Sturbridge. Information: (508) 885-3336.
Sunday - Star Island Striped Bass Tournament. Cash prizes and Calcuttas for best bass and blues. Information: (631) 668-5052.
Sunday - Free bird walk, New Braintree and vicinity with Rodney Jenkins, Forbush Bird Club. Meet at 7 a.m. at Winimusset WMA parking lot, Turnpike Road off Rte 122 in New Braintree. Information: (508) 757-5010.
Sunday - Singletary Rod & Gun Club meat raffle, 1:30 p.m.
Monday - New England Fly Tyers meeting, 7-9 p.m. every Monday at American Legion Tatnuck Post 288, 570 Mill St., Worcester.
Tuesday - Remaining antlerless deer permits for WMZs 10, 11, 13, and 14 go on sale at Mass Wildlife.
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|Publication:||Telegram & Gazette (Worcester, MA)|
|Date:||Oct 8, 2010|
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