Millions and Millions of Fish Grow Here

Front Page / Jul. 24, 2011 2:19pm EDT

By Ben Strange

Just months ago, tucked away in the White River National Fish Hatchery on Route 107 in Bethel, six million North Atlantic Salmon eggs lay in watery trays, waiting to hatch.

Also waiting, but on the word of biologists from the north end of the White River, hatchery manager Ken Gillette kept the eggs in water just cold enough to delay the process. Finally, when the water up north had warmed a little, Gillette turned on the heat in the trays just a tiny bit.

The facility, along with its six million soon-to-be Atlantic-bound salmon, also is a full-time employer to five additional permanent staff, two term employees and two college interns. Along with the salmon, they manage some 750,000 lake trout, eventually on their way to Lakes Ontario and Erie.

With a budget shy of $1 million, the national hatchery works towards the restoration of North Atlantic salmon to the Connecticut River and its tributaries, and the stocking of trout in the two Great Lakes.

After receiving a detailed explanation of the images displayed in the hatchery’s modest visitor’s center (depicting the life cycles of trout and salmon), Herald photographer Tim Calabro and I were treated to a full tour of the expansive facilities by Gillette.

The Hatching Process

The first room we stepped into had nearly 70 eight-foot diameter tanks, most of them filled with parr (fish in the early part of their life cycle) of either lake trout or North Atlantic salmon.

Parr, we learned in the visitor center, are characterized by the camouflaging stripes on their sides, which they lose upon leaving their nesting grounds in a process called smolting.

Lining the walls behind us were over a thousand trays that recently held fish eggs. Following the annual cycle, the center had emptied these trays in spring for the hatching of fry (the period preceding parr). All of these fry were taken and released in tributaries of the Connecticut River throughout Vermont, Connecticut, Massachusetts and New Hampshire,

The trays could hold an astounding 10,000 eggs each.

Gillette noted that during the process, some eggs will inevitably go bad, and that bad eggs had to be removed to negate the risk of contamination. Luckily, long ago were the days of doing this by hand. A machine using an optical eye sorts out bad eggs from good ones as the liquid in bad eggs congeals.

This year the facility put out anywhere from five to six million eggs—70% of which on average made it to the fry stage. Gillette noted that they are set up to do more than that if necessary, and recalled that one year they had as many as 12-13 million. 

“That was just too much,” Gillette said as he smiled.

Older Fish, Bigger Tanks

After showing us scores of fish of various sizes throughout the room of tanks, Gillette explained that fish are kept in these tanks until they are a year old, at which time they’re run through a pipe to the larger pools outside.

The outdoor pools, 56 in all, are home to fish anywhere from one to four years old. New technology allows an artificial current to be run constantly (necessary for the adolescent Atlantic Salmon) and provides filtration.

To deal with the wastewater that is produced by the pools, the plant has its own recirculation center for cleaning water at some two thousand gallons a minute.

We had the fortune of visiting on a transfer day—when some tens of thousand parr had been moved to the outdoor tanks. Gillette told us that by the end of the process the fish would have filled six tanks with 90,000 apiece. 

Throughout the subsequent years, these fish would be spread out to other tanks as they grew and as older fish were shipped out. 

Water

The system by which the facility gets and uses its water was simply astounding.

Four massive pumps, located at the back of the facility, are used to fill tanks, create currents, or move fish, drawing upon four primary wells. If used all at once, the pumps can bring 3000 gallons a minute into the hatchery.

During our visit, the pumps were running just shy of a measly 2000 gallons per minute.

If this isn’t enough, they also are set up to draw upon the White River, adjacent to the facility. However, such a situation is yet to arise.

Apart from filling tanks and creating currents, water is used to move fish between tanks. A massive pipeline starting from the smaller indoor tanks was in use to move thousands of parr to the larger tanks waiting outside.

The facility is able to regulate (quite accurately) the temperature of large amounts of water. Eggs respond directly to miniscule temperature differences in water and can be made to slow down or speed up their process.

For a late spring, the facility can cool down the water a bit, and correspondingly, the eggs will take longer to hatch into fry.

Will Salmon Return?

One of the tasks charged to the hatchery by the U.S. Fish and Wildlife Service is the restoration of North Atlantic Salmon to the Connecticut River and its tributaries, including the White.

There was a time when salmon were extraordinarily plentiful in the river, but due to dams, the dramatic migrations to the ocean and back came to an abrupt halt decades ago. Salmon have the remarkable ability to return to the area of the freshwater river where they were born after spending years in the Atlantic Ocean—there is some debate about how this is done, but the most prevalent theory is the use of scent or chemicals imprinted on the fish early in life.

Salmon, unlike many fish, require shallow water with a gravel base to lay their eggs. Unable to reach their tributaries, salmon cannot spawn.

Naturally, salmon would stay in their tributaries from the time they are hatched until the process of smolting, and which time they will work towards the ocean. 

All of the North Atlantic salmon eggs produced at the center are taken to tributaries as fry, and the center hopes that these fry will return someday to spawn as full-grown salmon. The center has had considerable difficulty producing good results, however.

“There was a bump this year, but certainly not the numbers we hoped for,” confessed Gillette. He said that so far 108 salmon returned to the Connecticut River to spawn—up from around 50 last year.

Still, the center has hope that some day North Atlantic salmon will return in plenty to the Connecticut River.

 

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