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Trout at 50 meters under the ground. A fish farm in the rock

The plant complies with technology regulations, and agriculture and veterinary watchdogs test fries twice and four times a year respectively, according to the deputy director

MOSCOW, April 3. /TASS/. If you travel some 70km from Murmansk towards Finland, you’ll see how different the nature there is with more coniferous trees; tall pines and firs, just like in central Russia; and magnificent snow caps on branches — what a beauty! Here, in the forest, you can barely see a cement wall with huge gates — the Upper Tuloma Hydroelectric Power Plant. It is absolutely unique as being located under the ground. And this is not the only surprise. Imagine, inside the power plant there is a trout farm.

268 megawatts under the ground

The 17 hydroelectric power plants on the Kola Peninsula make four cascades. The plant, which we enter through the gates, was built in 1962 -1965. The date is carved above the gates. Inside the rock, four turbines produce 268 megawatts.

The turbines have been in service here for 55 years, running as smoothly as a Swiss watch. But any watch requires tuning from time to time. The plant is now undergoing a big upgrade, after which every turbine’s output will be 8MW more. The overhaul actually hampered our plans of touring the place, and we headed straight for the fish plant.

Amazingly interesting …

The tunnel in the rock is 320 meters long. It runs downwards, almost 100 meters deep. The trout farm is at the depth of 50 meters. The power plant’s machines are under the ground, whereas the farm is mostly under the water reservoir, which collects water from the Tuloma River and Notozero Lake.

Small water streams glide down the granite walls. I am curious to learn how the farm works, why people agree to work under the ground, and whose idea it was to make a fish farm there.

"This is the only plant in the Murmansk Region, producing trout farming material, small fries, and the only plant in the world, which is under the ground," the plant’s owner, Arctic Salmon company’s Director Sergei Prudnik tells us.

"The power plant’s architects hoped salmon in the Tuloma River would use this fish corridor, they even made an elevator here. But there’s no fooling the nature. Only once salmon used the corridor in 1965, that’s it," he said.

This fish corridor remained unchanged until 1992, when scientists came forward with an idea of how this corridor could be used. This is when the corridor turned into a fish plant.

Finland’s Atria supplied and installed the equipment, which has been up and running for 28 years now. This is exactly the same number of years that Valentina Belyayeva has been working at the plant. She used to be a technology engineer, a director, and a deputy director now.

"I graduated from the Murmansk State Technical University as a trained fish technology engineer, dreamed of going out to sea, but life took a different turn. I have been working here for 28 years and I know everything about trout," she said with a smile.

The trout plant’s staff is only four people, including the director. This woman is responsible for the entire production process. The annual output is 1.5 million small fry!

Let's start with the hatchery!

Two dark rooms with shelves, which are separated from the other space by a black non-transparent curtain, a sound of rippling water, wet floor… This is where eggs are put into tanks, and in about a month they get ripe and small fries appear. The cycle from eggs to fries takes six months. Valentina calls this part of the plant a "kindergarten."

"It is very interesting: you put eggs, then watch how eyes inside eggs begin moving. Look. Some tanks are filled with eggs, in others there are larvae — they are very small — about 80 milligrams. They now are at the short stage when they may be disturbed, but there are periods, when larvae need absolute silence, darkness and, of course, certain water temperature and certain amount of oxygen."

Eggs need water of plus 10 degrees, fries — not more than plus 14 degrees. They do not have to warm up the water at the plant. Cold water from the reservoir gets mixed with warm water from the power plant providing ideal conditions for growing fries.

"They huddle up, clinging to each other, the process is called "fanning" — this is how they develop the reflex of imitation. Good reaction from the fry! At this age, they are bold, pushing away their relatives. Fight for life goes on," the deputy director told us.

As soon as the fry gets to the tank’s top, it may be placed into ponds — the shop has 28 ponds, each of 7m3. In three or four days, the "babies" swim, and the trick is to feed them on time. The process is automatic, "smart" equipment does the job in line with a certain algorithm.

"Here, you can see each of the 28 ponds. We get all the information: quantity of fish, average weight, temperature. Just look, the water temperature is plus 11.12 degrees, the feed is 5%. Every day, a fry eats 874 grams of feed — almost a kilo," she continued.

As fries grow, they are placed into different tanks depending on sizes. Feed is bought from Denmark. Russia does not produce fish feed. The plant works to orders, the demand is high, the director said.

"This year’s contract is for 1.3 million small fries. We sell them to Arkhangelsk, Karelia, and now the Murmansk Region has been buying them actively. Businesses open new aquaculture farms, mostly not big farms. On the Ura and Tuloma (rivers) <...>, tanks are installed right in the rivers, as trout will grow only in pure running river water."

Clients buy fries of 5-10 grams, then grow them and only later sell them to retailers.

The complete cycle to grow trout takes about 30 months. You may sell fish already after 18 months, or even 12 months, when it is about 300 grams, but this fish is popular with restaurants only as 30-35cm fish looks perfect across a plate.

Health is above all

The plant complies with technology regulations, and agriculture and veterinary watchdogs test fries twice and four times a year respectively. The director shows us a file of documents: every inspection has confirmed high quality of products.

"I say, our fish is clean, temperature is never high, the water is of the first category, due to the <...> purest-water reservoir, clear from any industrial waste," he said. "We use high-quality feed, a balanced complex of protein, fat, carbohydrates, minerals and vitamins."

Rainbow trout comes from North America, the technology engineer says. This species could have perfectly adapted in Russian northern rivers. However, businesses in Russia usually grow trout at farms, and into rivers they release juvenile salmon. The plant’s director opens another secret to us:

"Our fish expert Valentina is not just a professional, <...> she is a caring and uncompromising person. She may spend nights here, like now that the plant undergoes the upgrade process. At times, the upgrade works may require cutting off electricity, and fries are top sensitive to temperature fluctuations."

Valentina says she has got used to staying there overnight after many years at the plant.

"It’s my choice. One turbine is stopped for the night, and this is the time, which we might miss to turn on our pumps so that water could go to the first shop. Without warm water we may lose six months of work to grow fries."

Have you ever stripped fish?

The plant’s second shop is equipped with eight bigger fish ponds. Each is 42m3 and water pours into them right from the reservoir, without any warming.

Here, in the running water the grown-up fish live, aged between one and three years and needed to renew the spawning population. A good grown-up trout may spawn up to 6,000 eggs at a time, which can fill up about a 500-gram jar.

"I am the only one who strips those grown-up fishes. We never use anesthetics! Special solutions are available, but we do not use them either. We did try once, but fish recovers from them very painfully. Thus, I do everything myself within two days: on the first day I strip, and on the second I may strip additionally, if that’s needed. And they are all fine."

After spawning, fishes are week, and thus they are fed off hands, though every pond is equipped with feeders.

"In the wild life, trout may live for 20 years," the deputy director said. "Here, they may be in the spawning pond to the age of ten, but we prefer to keep them to the age of six, and every year we replace about 25-30%, and burn the old fish. That’s the rule."

"The spawning pond is home to about 600 fishes, plus male fishes, plus ‘extras’. Thus, at a time there may be about 6,000 fishes."

Polar Night's Rainbow

Fish can tell what season it is by the water temperature. In our bigger ponds the temperature is equal to water temperatures in a river: cooler in winter and warmer in summer. In warm seasons, trout is more active, it needs more feed, and in cold seasons all processes slow down.

"In the wild, spawning is usually in April-May, eggs grow from November to January. But here we can regulate the cycles. If we want, we may raise the temperature to speed up the process. And, on the other hand, we 'make' a polar night for the fish — almost like in the nature. Before the spawning, we separate females from males, as the males get ready much quicker."

I ask Valentina, how she can understand when it is time to separate them and to sort by the age.

"It’s elementary," she says with a smile. "They are so different. The girls are pretty, their noses are shorter, the bodies shimmer like a rainbow, their violet color is most bright, and girls are bigger than boys. The males are very different. They have big heads with heavy chins, and the body color becomes darker. Besides, they have a bright red strip along the body, in the spawning season it becomes crimson, and when the fish is playing, in the artificial sun you can see a shining rainbow!"