The Karelian Isthmus is a popular place for hiking, cycling, skiing ( Korobitsyno and Kavgolovo ), climbing ( near Kuznechnoye ), canoeing ( Losevo ), fishing for consumption ( of carp bream, northern pike, roach, European perch, ruffe, burbot and others ), mushroom hunting ( for porcini, red-capped scaber stalk, birch bolete, velvet bolete, slippery Jack, golden chanterelle, Lactarius resimus, woolly milk-cap, ugly milk-cap, saffron milk-cap, Lactarius rufus, various Russulas and others ), berry picking ( of bilberry, raspberry, woodland strawberry, cowberry, cranberry, cloudberry, bog bilberry and stone bramble ).

Its common names are ambiguous – " ruffe " may refer to any local member of its genus Gymnocephalus, which as a whole is natively endemic to Eurasia.

At full length, the adult ruffe is usually around 20 cm, but at a maximum of 29 cm.

Growth is usually occurs more when the ruffe is in clear, brackish waters.

If there is no intervention taken by the public the ruffe have the potential to ruin Lake Superior.

Not only has the ruffe become an inconvenience but, it is also the first invasive species to have been labeled a nuisance by the Non-indigenous Aquatic Nuisance Prevention and Control Program.

The ruffe and perch are competing in numbers and are also competing for food ; this is a match that the ruffe are winning.

If a large school of ruffe is found, they can be poisoned.

Second, the pheromone is species specific, so it would only repel the ruffe, none of the other fish.

Finally, the scientists found that it is resilient to freezing, so even during Minnesota's long winter season ; the ruffe could still be controlled.

By using this method there is a chance the ruffe could be prevented to go to their natural mating spots and therefore eventually the ruffe might die out.

The lake contains salmon, trout, pike, perch, minnow, dace, ruffe and eel, though the predominant species is roach, which is believed to have been introduced in the form of discarded live-baits by visiting pike anglers.

The population is threatened by deteriorating water quality and by the ruffe, a fish introduced to the lake in the 1980s and now eating the eggs and fry of gwyniad.

A Ruffe usually matures in two to three years, but a ruffe that lives in warmer waters has the ability to reproduce in the first year of life.

From here, the ruffe gradually mature until they are 2 – 3 years old, when they reach full maturity.

When injured, a ruffe will release this pheromone into the water to warn other ruffe to stay away.

48 forms ( species and infraspecific taxa ) of fish have been encountered in the lake, including roach, carp bream, zander, European perch, ruffe, endemic variety of smelt, two varieties of Coregonus albula ( vendace ), eight varieties of Coregonus lavaretus, a number of other Salmonidae as well as, albeit rarely, endangered European sea sturgeon.

Life, for the Eurasian ruffe, starts as an egg, like other fish.

The ruffe has similar eating habits, as well as having an accelerated reproduction rate compared to other like fish.

Therefore, having more ruffe in the water, leads to less food for other fish.

The ruffe has the ability to overtake many other fish species, and consequently damage the Great Lakes ecosystems.

The chemical lampricide TFM kills ruffe, but leaves other fish untouched.

The primary spawning season for the ruffe occurs from the middle of April through approximately June.

It shouldn't be too long for the ever so quickly reproducing ruffe to soon phase out any perch that stands in its way.

Ever since the ruffe was introduced into the Great Lakes system, scientists and fishery managers have been searching for the right way to get rid of them.

The ruffe also has a large, spiny dorsal fin likely distasteful to its predators.

The most obvious features to recognize a ruffe are the ruffe's large, continuous dorsal fin and its slightly downturned mouth.

The darters, perches, and their relatives are in this family: well-known species include the walleye, ruffe, and three species of perch.

** Donets ruffe, Gymnocephalus acerinus.

** Danube ruffe, Gymnocephalus baloni.

Of ruffe raffe roaring, with thwick thwack thurlery bouncing.

It also contains the endemic gwyniad, now listed as critically endagered by the IUCN due to the introduction of the invasive and non native ruffe.

They are dominated by the genera Gobio, Romanogobio, Squalius and Chondrostoma and contain such species as carp, Prussian carp, roach, bream, Silver Bream, pike, perch, ruffe, chalcalburnus, Sprattus, Mugil and others.

In Eurasia, the ruffe diet mainly consists of zoobenthos: chironomids, small aquatic bugs and larvae, which are all found in the Benthic zone of the water column.

The ruffe has the capacity to reproduce at an extremely high rate.

One week after the hatching, the young ruffe start to swim and feed actively, but they do not form schools at this age.

Generally, female and male ruffe do not live longer than 7 to 11 years.

The ruffe also has an excepional ability to detect water vibrations through organs called neuromasts.

This trait both aids the ruffe in finding food and gives the rudge an edge in avoiding predators.

The word `` mimesis '' ( `` imitation '' ) is usually associated with Plato and Aristotle.

The party is usually in a room small enough so that all guests are within sight and hearing of one another.

It will readily be seen that in this suggested network ( not materially different from some of the networks in vogue today ) greater emphasis on monitoring is implied than is usually put into practice.

One is so accustomed to think of men as the privileged who need but ask and receive, and women as submissive and yielding, that our sympathies are usually enlisted on the side of the man whose love is not returned, and we condemn the woman as a coquette.

usually, this is most exasperating to men, who expect every woman to verify their preconceived notions concerning her sex, and when she does not, immediately condemn her as eccentric and unwomanly.

What evidence is available would seem to indicate that Brooks, unlike his older brother Henry, had most of the methodological vices usually found in the amateur.

He is usually something of an underdog, he must battle the organized police force as well as recognized criminals.

he usually draws some kind of comparison with the jazz tradition and the poem he is reading -- for instance, he draws the parallel between a poem he reads about an Oriental courtesan waiting for the man she loves, and who never comes, and the old blues chants of Ma Rainy and other Negro singers -- but usually the comparison is specious.

This is a common symptom and the cause usually is pressure on the nerve leading to the affected hand.

if the Government certifies that production may be possible from the property, the royalty obligation continues for the 10-year period usually specified in the contract or until the Government's contribution is repaid with interest.

These roads are largely of less than highway standards, and usually carry traffic which is related to use of the National Forests.

April 15 is usually the final date for filing income tax returns for most people because they use the calendar year ending on December 31.

Much of this necessary increase in research and development, though properly chargeable to current expenses, is not reflected in earnings until projects are completed and the new machines sold in quantity, usually over a period of several years.

Sometimes it is necessary to roughly calculate the square inch area of the opening but the calculation can usually be made with sufficient accuracy that it won't affect the final computation.

Enough daylight is usually available from the windows, but if you have synchronized flash -- use it.

The size of the press is usually expressed in terms of chuck capacity ( the maximum diameter tool shank it will hold ) or distance between the spindle center and the column.

We know now that a 15-degree differential in temperature is the maximum usually desirable, and accurate controls assure the comfort we want.

It is usually helpful to make a sketch map in the field, showing the size and location of the features of interest and to take photographs at the site.

A body of water is usually the center of interest at parks which attract the greatest picnic and camping use.