Which fish is considered weedy? These are species that are of little value, disadvantageous for fishing, and harmful to other populations. Their unprofitability is determined by slow growth, small size and low nutritional value. In fish farms, such a trifle complicates sorting, in nets clogs the cells and reduces the profitability of the catch.
Weed fish displace other, more valuable species in water bodies by eating their eggs and resources of a common food supply. However, some of them, despite the small size, are of gastronomic interest.
Harm
Rapidly breeding and holding in large schools, weed fish threaten populations of other, larger and more valuable species, eating up to 80% of their eggs in spawning, and sometimes completely destroying it. Larvae and fry of bream, pike, common carp, ruff, pike perch also become food for small predators.
The surviving juvenile of commercial fish that feeds on phyto- and zooplankton may not survive due to a lack of food if their natural food is absorbed by weed fish. This situation is a particularly acute problem for small enclosed bodies of water. In addition, these small numerous small fish often become carriers and pathogens of diseases caused by parasites or bacteria.
Benefit
It is difficult for some fishers and trappers to believe this, but the weedy freshwater fish, also called wild, has several advantages:
- It supports the biological diversity of water bodies.
- It is a food base for valuable predatory fish such as perch, asp, pike, catfish.
- It feeds on waterfowl ichthyophages (storks, herons and others).
- It eats in huge quantities of sludge, unicellular algae and bacteria that form the biological fouling of water bodies.
- Loach, ruff, gudgeon and some other types of weed fish have good taste and are appreciated in amateur fishing.
- In some regions, ruffs, bleak, roach can be of commercial importance because of their large specific gravity.
But such wild fish tend to breed excessively and quickly. This problem is especially relevant in small enclosed bodies of water, for example, in ponds. Therefore, the size of its population must be controlled.
Types of struggle
Despite some advantages, the harm from weed fish is more than good. Among the methods of dealing with it, trash traps are used - devices in the form of various forms of boxes with a metal mesh. They are installed on a watercourse (canal, pipe) during the filling of ponds. A thorough annual fishing will also give a good result. Reduces the number of weed fish and increases the productivity of commercial ponds rearing fish of prey. These are one-year-old pike, two-year-olds of large perch.
Where and which fish is considered weedy
In Russia, the most malicious parasite is rotan, which has become a real disaster in many reservoirs. Abroad, it can be other types, even those that are considered delicatessen in our country.
In some states, crucian carp, catfish and other fish enviable for a Russian fisherman are on the list of weeds. For example, in Australia, for some time now, carp have been ranked among these, which in most European countries are bred in fishing ponds. But in the warm Australian climate, it breeds too quickly, creating a dangerous competition for the original inhabitants of local lakes.
In non-commercial water bodies, not all small fish are considered weedy, but only one that threatens the existence of other inhabitants. Many of these species have a fairly high taste and are deservedly appreciated by culinary specialists. The main quality that gives the right to call the weedy fish is a reduction in its number or crowding out other species.
Which of these representatives are common in Russian reservoirs? The most “harmful” can be called the head-rotan, ruff, bleak, vodhovodka, stickleback. The list of “wild” small fish also includes char, loach, gudgeon, goby, smelt, three-needle, Amur roe, minnow, snapper, pinch and others.
Rotan firebrand
The original habitat of this gluttonous fish was the Far East. In the mid-20th century, rotan spread to other regions of Russia. Having successfully acclimatized, he entered most water basins. Like a fast-breeding predator, rotan in a small pond is able to quickly exterminate all other types of fish, eating their eggs, fry. They attack adults, but small-sized inhabitants of the reservoir.
Rotans are cannibals. By catching them, one can often find the so-called nesting dolls when another is in the mouth of one fish. Sometimes you can count up to 4 - 6 individuals swallowed along the chain.
The size of the fish is 10-15 cm with a weight of about 200 grams. Sometimes the largest specimens weighing up to 500 grams can reach 35 cm. This species has an amazing ability to survive in polluted reservoirs, withstands complete freezing and partial drying of ponds. Rotan lays up to a thousand eggs per season. Its number can be regulated by predatory fish: perch, pike, catfish, eel, zander, asp, trout. Delicate dense rattan meat tastes great. As a bait, this hardy fish is able to "work" all day.
Ruff
This is the most common weed fish in Russia, very gluttonous and unpretentious. The length of her body is not more than 20 cm, and weight - 100 grams. Ruffs love cool water. They rarely rise to the surface during the day, and they are kept in large flocks at a fairly large depth, closer to the bottom of the reservoir. Spend most of the time in ambush, looking for prey. At night, the ruff is highly active and floats into small places.
He eats in the daytime and at night. As it grows, it eats in huge numbers the eggs of other fish, which it drives away from their food places until it eats itself up. Therefore, in some ponds and lakes, ruff becomes the predominant or only species. Big perch, pike perch, pike, burbot are the natural enemies of these weed fish, regulate their population.
Stickleback
This is a very small and ubiquitous fish. It can become a real scourge of fisheries. Its size is 4-10 cm, and the life expectancy does not exceed 3 years. The stickleback lays no more than 250 eggs, but it is an extremely greedy and gluttonous weedy fish.
It not only eats caviar of valuable commercial species, but also deprives them of food, which it itself absorbs in huge quantities. Thanks to spiky needles at the dorsal fin and on the abdomen, the fish remains invulnerable to predators such as perch and pike.
Bleak
Low value fish. Her body is no longer than 20 cm. Keeping in packs, bleak prefers slowly flowing deep water. Relative to thermophilic, these weedy fish usually stay in the upper layers of water bodies in areas free of vegetation.
Bleeding is very gluttonous. She spends all day hunting. It feeds on plankton, lower crustaceans, insects and pollen that have fallen to the surface of the water. Large specimens eat caviar and juveniles of other fish species. In spawning, the bleak lays up to 4000 eggs.
Conclusion
If one of the species disappears in nature, others begin to develop rapidly. Weed fish are the natural food of freshwater predators. When they are actively caught from water bodies, a trifle begins to multiply rapidly. Every fisherman wants to catch a large fish. Many throw a trifle back into the water.
Over the past decades, many new devices and fishing methods have appeared, fishing has become more effective. This led to a catastrophic increase in the number of small fish, which is very difficult to get rid of in water bodies.