Fixed nets. Analysis of the structures of fixed seines

Luxol

Set nets from the group of traps are the most common. Their principle of automatic fishing and the ability to keep the fish alive attracts a lot of attention from specialists.

The catchability of the fixed nets depends on the factors affecting the entry of fish into the yard and into the chambers, and their holding capacity.

a guide wing, which serves as an obstacle to the movement of fish and makes it change the direction of movement towards the location of the camera;
an inlet that facilitates the entry of fish into the trap and makes it difficult to return from it;
a chamber (boiler, box, cage) that holds and keeps the catch alive from one check to another.

The set seine is a rectangular net chamber with adoptions in the form of vertical doors. Adding a wing increases the entry of fish into the camera.

Fixed seines - application

It was found that the use of wings with a length of more than 18 m for carp fishing is impractical, since in this case the carp does not enter the trap, but after passing along for some time it turns around. The recommended wing installation angle is 30°, if the trap has one, the angle between them should be 60°.

To catch marketable fish in fattening ponds, it is best to use two-chamber traps with a length of 5-8 m, a width of -3-5 m and a height of at least 15 m. be often cellular with a cell pitch of 20-26 mm and from a thick thread of 93.5 or 187 Tex. In this case, the wings and the first adoptive child can have a pitch of 25-35 mm.

What does the marking tex mean?

Carp and silver carp are very careful, so it is better to leave such traps open at the top, or close the large-meshed delyu.

The advantage of a set net

The advantage of such fishing gear is the autonomy of their action. The fish remains alive for a long time and all the work of the fisherman is reduced only to the selection of a protege. In addition, such fishing gear can be used in places inaccessible to seine fishing.

Stavniki are installed on stakes, frames or floats and braces with weights and anchors. It is necessary to unload the fish from the stalkers from the boat, lifting the bottom of the stalker from one edge (input), moving it to the opposite wall and driving the fish into a corner where it can be selected with a net.

It is better to install traps in places with dense vegetation and mask the entrance to the trap. The del mesh used for the construction of fixed seines must be painted green or brown.

luxsol.ru

Commercial fishing gear in fish farming

How fish are caught in pond and lake fish farming

In the practice of fishery development of inland water bodies, including water bodies for complex purposes (VKN), various tools are used to catch fish, but active fishing means are preferred.

Regardless of the methods and gear used, water bodies must first be prepared for fishing:

carefully examine the bed and banks;
clear the water area from floating objects, trees and shrubs protruding above the water or connected with the ground;
remove alloys;
clear the bottom of sunken objects; align the bed;
perform other tasks depending on specific conditions.

According to the principle of operation, fishing gear is divided into three groups.

The first one is called “enveloping” networks. Their principle of operation is based on the fact that the fish gets stuck, or “enclosed”, trying to pass through the nets installed in the form of a wall in the way of its course. The net cloth in such tools is made of a thin thread and either cuts into the body of the fish or confuses it. In VKN and on small lakes, fixed nets are used, which remain motionless in one place during the fishing process. Their catchability is low and in comparison with other tools does not exceed 14-15%. Fixed networks are widespread. They catch fish different types. In ponds, single nets are used, and for catching larger reservoirs, the nets are connected in series into a long wall, the so-called net order.

The fixed net (fig.) is a rectangular canvas, planted on the upper and lower pick-ups and sometimes on the side veins.

Types of fixed nets: simple; b - cutting.

The rebounds are made longer than the planted web of the network in such a way that free ends 0.5-0.8 m long protrude from each of its sides. These ends, called priukhs, are designed to connect the networks in a net order. Sometimes priukhs are made in the form of loops. Nets are planted with a coefficient of 0.5! Floats made of polystyrene (melt) are attached to the upper selection, sinkers are attached to the lower one. The number of those and others depends on whether the network will work afloat or will be deepened. According to the device, the fixed nets are simple and “thin”, sometimes they are called two- and three-walled, depending on the number of net walls.

For fishing areas with a depth of 1.5-2 m, the nets are installed on poles, with an increase in depth - on anchors. The first net is tied up in such a way that the lower end of the pole is at a distance equal to the depth of its driving into the ground from the lower end of the pole, and the upper one is tied up depending on the height of the net. The other end of the network is tied in the same way to the second pole, the lugs of the first end of the second network are attached to it, etc. The prepared networks are loaded into the boat and taken to the installation site. On poles, they are usually installed for one night or a day, but sometimes for a longer time. In the first case, the catch is chosen simultaneously with the removal of the net order, and in the second, they are sorted out at least twice a day, removing the caught fish.

Even more common is the installation of fixed orders at anchors both in shallow water and in depth. Stones, bricks and other improvised materials are used as anchors.

The second group consists of screening tools in the form of a net wall of various shapes. Having swept over a part of the reservoir, the tackle is sunk ashore or on a watercraft. Water passes freely through the meshes, the fish lingers, but does not get tangled or bundled up, but remains on the canvas or rolls into a bobbin. Fishing in these cases is undesirable and even harmful, as it slows down the work and reduces the productivity of the fishermen. Therefore, netting is made from coarser threads and with a finer mesh than that of nets. The most widely used of this group of tools were cast nets. The seine is considered optimal with a length of at least 1/3 of the perimeter of the reservoir. A throwing equal-winged net (figure below) consists of two identical wings, two drives and a bobbin.

Scheme of an equal-winged cast seine: 1 - wing; 2 - drive; 3 - skein 4 - outlet (shirt) skein; 5 - upper selection; 6 - lower burr; 7 - floats; 8 - weights; 9 - nag; 10 - bridle; 11 - edge.

The wings are designed to cover the fished area of the water area and represent the longest part of the seine. They are made from a relatively light and large-mesh case, and sometimes composite: canvases from a heavier fine-mesh case are placed in the center. This distribution of delhi is explained by the behavior of the fish: at the beginning of the seine operation, it does not seek to leave the swept area, but as it sinks, it tries to leave the seine. This is prevented by the part of the wing remaining in the water. The height of the wings to the ends (nags) is reduced so that when they sink, they are the first to go ashore.

The drives are used to guide the fish into the motna. They are made from a thicker thread and a small-mesh deli 20-40 m long and sewn with a bobbin.

Nets are planted on rebounds with a coefficient of 0.5. A melt is attached to the top, a load is attached to the bottom, and poles or nags are attached to the side edges. They straighten the ends of the seine, preventing the rebounds from folding when sinking. Ropes are tied to the nags, ropes are pulled for them. Catching marketable fish from the VKN is the most difficult and time-consuming task. The greatest effect is given by throwing seines of large sizes. Their catchability increases in proportion to the area of the wrapped space, which is confirmed by the experience of total fishing of small lakes in the Novgorod, Pskov and Leningrad regions, as well as some VKN of the Stavropol Territory.

According to the Pskov branch of GosNIORKh, the total fishing did not have a negative impact on the ichthyofauna of small lakes in the North-West. Moreover, there is a qualitative improvement in its composition due to the removal of low-value species. A sparse stock of commercial fish makes better use of food resources and gains market weight faster.

An elongated pond is recommended to be caught with longitudinal tones, when the seine covers it to the full width. If fishing is carried out with one seine, then the reservoir is blocked with fixed nets into two parts. This makes it possible to filter almost the entire water mass, and the number of tons depends on the length of the reservoir.

In this case, it is recommended that the seine is 1.5 times longer than the maximum width of the reservoir and 5-6 m high with flared wings.

In silted reservoirs, the lower selection cuts into silt. To avoid this, the so-called “valance” is sewn to it, and the seine moves more easily along the muddy bottom. To facilitate the fishing of non-drainage reservoirs, since autumn, water is partially pumped out of them with pumps.

Practice has shown that the bulk of carp and carp are caught in the first ton. In the next tony, their catch drops sharply, as frightened fish leave for hard-to-fish places. Therefore, the first longitudinal tone must be carried out especially carefully.

Fishing brigades in the Stavropol Territory successfully use long seine nets to catch stocked reservoirs with fish. Each team consists of 12 people: a foreman, two minders, a cook and eight fishermen. A caravan of five boats is formed at the pier:

the first is equipped with a stationary engine with a capacity of 11 liters. With. and a winch driven by a Vyatka motor;
the second is a seine net (750 m long seine is laid in the stern of the boat, the upper line is laid in loops, the lower line is in rings);
the third is equipped with a 1000 m long cut (cable with a diameter of 30 mm);
the fourth has an edge and a winch (a truss with rollers for normal cable feeding is installed in the bow); the fifth is intended for the transportation of caught fish.

The formed caravan, as a rule, goes to the baited ton, but if this was not done in advance, then the foreman goes on the lead boat and “gropes” the fish sixth. An experienced fisherman on the go feels how a fish hits a pole, and in this place the seine begins to notice.

The first and second boats, without slowing down, sweep the seine in a semicircle, moving away from the shore for the entire length of the edge. The sinking begins immediately after the net is swept out, pulling both wings at the same time. The spotted wing is one and a half times shorter, so it is pulled out first, the nag is fixed with a steel pin on the shore, and the upper line is thrown onto the boat (rice).

Scheme of seine netting: 1 - edge; 2 - wing (goes from the shore); 3 - motna; 4 - fugitive wing (larger); 5 - edge; 6 - non-water; 7 - motor boat.

The third group is represented by traps or stationary fishing gear, which account for no more than 5% of the total fish catch in our country. Such tools (fig. below) are especially suitable for catching snarled water bodies. Venter is a net cylinder, or barrel.

Fixed fishing gear: A, B, C - ventery; G - fixed seine.

When cast, it lies on its side on the bottom of the reservoir. At one end, the barrel has an opening for fish to enter, and at the other end, it ends with a net cone called a cod, or a cod. In working order, it is held by wooden or metal hoops - casters. The diameter of the input coil, as a rule, is larger than the others. The length of the vents ranges from 1 to 20 m, and the diameter of the inlet cauldron is from 0.5 to 5-6 m. Inside the barrel there are net necks, or weasels, in the form of truncated cones, with a wide base directed towards the exit, and narrow - inside the vent. They direct the fish inside the barrel and do not allow it to go back.

To increase catchability, the barrel is equipped with wings from 5 to 200 m long. They block the fish from the bottom to the surface and direct it into the vent. Several additional small wings, the so-called openers, serve the same purpose. Fish caught in the vent accumulate and remain in it. During inspection, small-sized venteri are taken out of the water entirely, and for large ones, only a cod, the end of which is unraveled and the fish is shaken out into the boat.

According to the principle of operation, the fixed nets (stavniki) are similar to the vents. They are most widely distributed in marine coastal fisheries.

It must be taken into account, however, that the use of a large number of passive fishing gear of various designs or small seines requires a significant expenditure of effort for their maintenance and does not allow the widespread use of mechanization. As a result, fishermen's labor productivity is low, the cost of fish caught is high, and the resource base of reservoirs is not fully utilized. G. Servetnikr Candidate of Agricultural Sciences

www.ya-farmer.ru

Fishing with fixed and smooth nets

One of the main fishing gear for salmon fishing is the harve net.

Garva is an old fishing term that was used in medieval Russian chronicles, and comes from the Sami word "harrv" - this is how the natives of the Kola Peninsula and the northern part of Scandinavia called their salmon fishing nets, which were used at least from the end of the last millennium.

It is unlikely that the Saami "harrivs" resembled the current garves, at least in the middle of the nineteenth century V. Dal in his dictionary gave the following definition of garves: "a fixed net for salmon, 10 sazhens long, 3 sazhens wide, meshes 1-2 inches".

But by the end of the century, the harves had grown significantly in size, and the dictionary of Brockhaus and Efron reports: "The length of the harves is different and sometimes reaches several miles."

The length of modern harves used for fishing in fresh water is at least hundreds of meters, height 8-9 meters, mesh 70-100 mm. It is possible to stretch a network of this size in water only with floats with a large carrying capacity (the so-called "cubas" were used before, now they have been successfully replaced by plastic bottles from soft drinks). They put the orders of the harves not in a straight line, but in a rather tricky labyrinth, in search of a way out of which the salmon get entangled in the cells.

The large size (combined with a hefty price) makes this tackle “unbearable” for amateurs, both figuratively and in the literal sense of the word - it cannot be set up from an ordinary boat. And the fishery supervision does not issue licenses for the use of harves to lovers, they are too big and catchy.

However, there are "amateurs" - they catch with harves in Lake Ladoga, and even more often in Onega. Often, when trolling on these lakes, spinners and wobblers are hooked on harves that do not have any identification tags required for fishing gear. But such fishing can be called "amateur" only in quotation marks - the same fishing, only underground.

If harves are used on wide reservoirs, which cannot be blocked from coast to coast, then on the relatively narrow rivers of the Kola Peninsula, a different method of installing nets is used: they are stretched across the river, in parallel, at a distance of no more than 2 meters from each other. Usually the river is blocked by 3 nets, sometimes their number in one place reaches 5–6. The meaning of this setup is as follows: salmon sees the network well in clear water and does not want to go into it. But instinct drives the fish to the upper reaches, to spawning grounds - it jumps over an obstacle and immediately finds itself in front of the next one, having no free space to accelerate before a new jump. And if he somehow contrives and jumps over the second net, then the third is ahead, and so on.

But this only happens in theory. In fact, the salmon, which manages to jump on two-meter waterfalls (also having almost no space for overclocking), often effortlessly overcomes the obstacles set by a person. Here is a small sketch made by a visiting St. Petersburg spinner who made his debut on the rivers of the Murmansk region (V. Makeev, “For the first time on Kola”, “Rybolov” No. 4/2000):

“The next day we decided to fish on the Kuz River, which is only 20 km from the village (from Umba - A. Sh.). From everything it was clear that the fish inspection put a big cross on this river - it seems that it does not exist here at all, and, as a result, there is no salmon - poachers almost completely knocked it out. But the remnants of the once large herd stubbornly went to their native river, overcoming one after another the placed nets.

We saw the poachers almost immediately, they, lounging on the grass, looked towards the river: what if some fool, flying into the net, still tries to get out of it. After questioning them, we were horrified to learn that the nets on this river cost no less than 50-60! They completely crossed the river, and besides, in two or three rows: salmon is a smart fish, the net jumps over, but, having overcome one, flies into another with acceleration. One fish can be exchanged for 6 bottles of vodka, so they guard it day and night, not thinking that it will disappear in this river forever.

And yet, by some miracle, part of the salmon nets passes!

Emotional opinion. A visiting sportsman might think a little: the locals have been catching salmon in this way since time immemorial - but it has not ended yet ... He could, but he did not think. Didn't want to. Or failed.

But another opinion, more balanced, is the view on the Internet of the problem of the nets of the Kola fly fisher A. Sokolov, presumably, somewhat better than mr Makeev familiar with local realities:

“At the same time, there are people who fish for sale with sports equipment - spinning and fly fishing. During the season, some of the most “efficient” manage to catch up to 200 tails, and this is not somewhere on the Varzuga teeming with trifles, but on Kolya! And that's for one person! The fishing mode is simple - “caught-in-the-bushes”.

At the same time, in the network in June and July, there really isn’t much - I shot a lot of networks at that time on Kolya and Kitsa - empty. Salmon is not a fool, he sees the net well. And blocking the river from shore to shore with about 5-6 nets set every 2 meters in order to net the fish jumping over the net does not help. But in autumn, with dark long nights, the nets become catchy. Yes, and belts, too, and floating.

I have said more than once and I will repeat: there are no predatory gear, there are predatory fishermen. What causes more damage to salmon populations - nets or fly-fishing - is a moot point. But it should be noted a curious fact: in the middle of the 20th century, when the use of nets on the Kola rivers was practically not limited, and spinning rods on their banks were a unique phenomenon, many times more salmon entered the rivers.

Some athletes are in favor of such a radical solution to the problem: to ban the nets once and for all, to follow the implementation of the ban in the strictest way, and to catch sports gear according to the principle: “catch and release”.

In response, I can only give one more quote, this time from myself, my beloved (from the preface to one of my books):

“Oh yes, there is also the famous principle: “catch and release”. But after all, not everything is so simple with him either ... They use it massively in licensed fishing on spawning salmon rivers. They say that the athlete will amuse himself, and the salmon will spawn, give offspring ...

Oh is it? After all, salmon does not feed in the rivers: it grabs a fish that has turned up, bites in half and throws it - instinctively takes care of the fate of the offspring, reduces the number of lovers to feast on salmon caviar and fry. The entire energy reserve for the long journey to spawning grounds and for spawning itself is in the fat accumulated by fish over the months of marine life. And that supply is barely enough, barely enough, - the salmon roll back into the sea, emaciated, exhausted to the last degree.

And if a considerable part of that reserve was spent on a long, furious struggle, on attempts to get away from the spinning sportsman-lover of nature? And if we add the consequences of traumatic shock? You can’t discount the nervous shock from being in the hands of people (you can’t do without a photo session with a defeated fish, it’s unsportsmanlike). Are there any chances for a successful spawning after all this? Okay, let's say they stay. Tiny, but they remain. So after all, there is a new license area ahead, and again the lure falls in front of the nose of the salmon, and again the instinct makes it grab ...

I am not saying that if the caught salmon is salted, then there will be more fish in the rivers. But somehow it will turn out more honestly, without the sanctimonious sports hypocrisy ... "

However, let's return from discussions about poaching and sportiness to catching salmon with nets. For fans of more than garves, small orders are available from the relatively short nets allowed by the rules. Naturally, they are used not in large lakes, but in relatively narrow and not turbulent sections of rivers.

L.P. Sabaneev described such orders under the name "veils":

“Setting nets (for salmon fishing - A.Sh.) are divided into curtains and harves. The first consist of two fixed nets, approved on stakes; one of the networks - the "wall" - goes from the coast perpendicular to its direction; the other network - the "factory" - adjoins its middle to the first, going to it perpendicularly, therefore, parallel to the coast; a "cache" is attached to the ends of the plant - a network in the form of a semicircle, facing the wall with a hole; access to the cache is narrowed by two networks, which leave between them only a small passage - the "gates". The salmon, walking along the shore, rests against the wall, turns along it, rests against the factory, turns again, and finally comes across through the gate into a hiding place, from where it is already difficult for it to get out.

A rather vague description, but the classic did not give a picture that clarifies the essence of the matter. However, it is clear that the orders of gill nets used today differ little from “curtains” - the principle is the same: put up a barrier in the way of a salmon going against the current and wrap it in a tight corral, surrounded on all sides by a net.

Where amateurs are allowed nets up to 60 m in length (or two thirty-meter ones), you can still try to set up something like a “curtain” alone; where it is possible to fish with only one net 25–30 m long, at least two people must go fishing (moreover, each fisherman must have his own personal permit; however, many of our fishermen despise bureaucratic bureaucracy and do fine on dark nights without pieces of paper with seals).

On fig. 17 shows an order of two single-walled thirty-meter nets, installed near the shore on stakes driven into the bottom. In the same way, by proportionally increasing the indicated distance, it is possible to stretch two 60-meter networks, the main thing is not to violate the proportions: the BVG and EZhZ angles in the figure shown should not exceed 35–40 degrees.

Rice. 17. The order of two 30-meter nets for catching salmon. Distances between stakes: AB - 30 m; BV and VG - 6 m; HL and DE - 3–3.5 m; EZh and ZhZ - 6 m; ZB -1.5 m.

Special "salmon" nets are quite expensive, so sometimes two types of nets are used in one design. For example, in section AB, an ordinary “bream” net of twisted thread is pulled into a straight line (salmon almost never gets tangled in it, and it only performs a guiding function), and a polygonal figure is built from a special “salmon” one.

Theoretically, a guide net can be made from any equipped net, for example, from a wing from a seine net - this is how the fishermen build their stabs. But in practice, it is impossible to implement such an idea: salmon nets are always placed near the bank closer to which the midstream of the river is located, and a strong current does not allow the use of nets with a large windage (strong - in this case only in comparison with the current near the opposite bank; do not set up a network on a real rapid).

Why "bream"? Why not some partial fine-mesh? For several reasons. Firstly, every little thing will not come across and distract from serious fishing. Secondly, due to the increased mesh size, the net will catch less fallen leaves and other debris floating down the river in autumn. Thirdly, salmon may not notice a net designed for small fish - that is, usually tied from a thin fishing line - and foolishly fly into it. An event that is sad not for the salmon, but for the net and its owner - in the morning, instead of the caught fish, a large hole in the net will be found. And large-mesh gill nets for catching spring caviar bream in our places are knitted from twisted nylon thread, thick and coarse enough (for some reason, the bream goes into such a net more readily than into a thin line, perhaps in search of objects that it "rubs" against, squeezing out caviar and milk). Such a tackle holds salmon, although it rarely comes across it.

But the usual “bream” net needs some refinement, primarily to be equipped with additional floats and sinkers (especially if it uses cargo and floating cords with weights and floats woven inside - such nets are only suitable for calm water, and they are installed on rivers in backwaters, bays and along coastal grasses).

As additional sinkers, large (18–20 cm in diameter) and heavy rings from a five-millimeter metal bar are tied up; a foam float is attached above each ring. Lead cast weights are inconvenient to use - they fall into large meshes of the net, confusing the tackle.

The carrying capacity of the floats is determined experimentally: they take a float, obviously larger than necessary, tie a ring to it and lower it into a barrel of water. Then the float is reduced until it, together with the ring, begins to sink quickly, reaching the bottom of the barrel in 2-3 seconds; the resulting float is used as a template for making the rest.

The gaps between the additional floats and sinkers depend on the initial load of the net and on the strength of the current in the place chosen for fishing, and can range from 0.5 to 1.5 meters. More often than after 0.5 m, it makes no sense to tie them: if the current “lays” the network anyway, you can tie anchors to it every 5–6 meters (heavy, several kilograms, metal weights or stones of the same weight), and over each anchor, tie a plastic two-liter bottle to the top selection. To prevent the network from deforming in water, a vertical vein is passed through its cells at the points of attachment of anchors ( nylon cord 1.5–2 mm thick, and slightly less than the height of the net in the landing), tying its ends to the upper and lower selection.

If the anchors do not help to keep the net in the correct vertical position - look for a new place for fishing, with a calmer current.

Now let's move on from the auxiliary net, stretched perpendicular to the shore, to the main part of the tackle - to the one that actually catches the salmon.

It is best to purchase a branded Finnish or Norwegian-made salmon net with a mesh of 70–80 mm (this mesh size is most optimal for Luga salmon, in places where larger salmon enter, it is possible to use a mesh of 100–120 mm). Imported salmon nets are made of multi-monofilament thread - the name is complicated, but, to put it simply, among the materials from which the nets are knitted, this thread is the same as the “braid” among the fishing lines: with a small thickness, it is distinguished by increased strength.

The best networks are connected without knots, there is also such a technology for machine networking: the intersecting threads that form the cell of the network are not connected, but are, as it were, woven into one another. Usually commercially available salmon nets are correctly planted, but sometimes they still have to be loaded, adjusted to specific fishing conditions; however, this is not such a laborious task, in comparison with knitting and planting.

The only disadvantage of the Norwegian and Finnish "salmon", especially knotless ones, is the high price. Therefore, many people use home-made nets: they either knit the net fabric themselves, or put it on the rebounds. In the first case, I do not advise using monofilament, although with a thickness of 0.4-0.5 mm it keeps entangled salmon. But the problem is in the knots: monofilament is generally quite slippery compared to twisted nylon threads, and requires a more complex knot, or a double ordinary one, otherwise it will “creep”; on a thick monofilament, it is especially difficult to tighten such knots and they turn out to be bulky, sloppy - the nets with them catch the garbage floating past more, and the fish are reluctant to go into them.

On commercially available wood nettings, the knots are small and neat, but a tricky technology is also used there: the threads only at the knots heat up to a certain temperature, and stick together, fuse, - as a result, a simple knot does not “creep”. A factory-made monofilament line is suitable for a salmon net, but the trouble is that it is almost impossible to find linen with a mesh of 70-100 mm and a line diameter of 0.5 mm on sale - the circle of possible buyers is too limited.

Large-mesh canvases made of twisted nylon thread are found on sale much more often - they are usually used when planting a salmon net on their own.

Landing methods are somewhat different from those used in the manufacture of a conventional partial network. If in a network designed for small fish, on the so-called. “Firing flint” or “posad” (a piece of landing thread between two knots attaching it to the lower or upper pick-up) is freely strung from 4 to 7 extreme meshes of the net, then in salmon nets - no more than two, and then with a relatively small mesh (60 -70 mm), and in large-mesh nets (over 70 mm), each cell is attached to the rebounds (a similar landing is used in the manufacture of nonsense).

Rice. 18. Planting a large-mesh salmon net.

Only in those cases when the point of attachment of the landing thread to the pickup falls on the float, in any case, two cells are planted on the "flint" (the dimensions of the float do not allow it to be placed between the cells). The above-described rings made of a metal bar are used as sinkers, and for their fastening it is not necessary to double the length of the “flint”.

Rice. 19. Planting a salmon net at the place where the float is attached.

The floats in advance, before the start of the landing of the net, are strung on the cord of the upper pick-up and fixed with wooden wedges at a given distance from each other. The sinker rings are then tied to the assembled net, each exactly under the float. It happens that, according to the conditions of fishing, you have to use very large floats and very heavy rings - in such cases it does not interfere with connecting them with vertical veins, as described above.

If you need a particularly heavy load, then it is undesirable to increase the diameter of the load rings too much. At the same time, it is difficult to bend them from a very thick bar - it is much easier to connect two rings together by attaching one to the other and fixing it with electrical tape.

Cords for picking up and landing thread are used with increased thickness and increased strength. Landing knots also need to be knitted more reliable: for example, Finnish anglers use the knots shown in fig. 20.

Rice. 20. Extra strong knots for planting salmon nets.

The landing coefficient of the net along the length is standard, 1 × 2: i.e., a 30-meter net should be obtained from a 60-meter doll. Nets with a landing coefficient of 1 × 2.5 (just such a landing is shown in Fig. 18) are more catchy, but in rivers they are applicable only in places with a weak current, that is, extremely rarely - mainly such nets are caught in the flowing lakes of Karelia and Kola peninsulas.

The stakes for installing the net are cut down strong (alder and similar trees are not suitable), with a thickness at the top of at least 3–4 cm; if the lower end is too thick at the same time, the excess wood is squeezed off it.

Each stake is tied in turn to the net in advance at two points, to the lower and upper pick-up (to the bottom - stepping back from the end of the stake to a distance equal to the penetration of the stake into the bottom soil), and then driven into the bottom with a sledgehammer and a simple device called " nabionnik ”- a piece of a metal pipe impaled on a pole.

Usually the stakes are hammered so that they do not reach the surface of the water by 5-10 cm, which makes the exposed tackle invisible from the outside.

There is another way to install a single-wall salmon net, much easier, but much less efficient. It is used in shallow places where for some reason it is impossible to stretch the net in the form of a trap: a rocky bottom that does not allow stakes to be driven in, too strong a current, etc. alone.

The simplified installation is called “weather vane” - one end of the network is firmly tied to a stake or a metal pipe, and it itself is freely pulled out by the force of the current, not fixed in any way, and oscillates like a weather vane, or rather, like a big flag in the wind. To avoid twisting the network into a bundle, the so-called. is tied to the far end of it. "nag" - a wooden six, equipped with a load at the upper end, and a float at the upper end; the load is selected so that the nag stands vertically in the water, but only its float remains on the surface.

The length of the nag should be significantly less than the height of the net in the landing (for example, for a net with a height of 1.8 m, a meter nag is enough). Along the entire length of the net, every 3-4 meters they put vertical veins equal to the length of the nag. Heavy sinkers with this method of fishing are not needed, the net must have positive buoyancy - it is enough that the weight cord gives it a vertical position in the water.

Such a net is already a cross between fixed and smooth nets, which are described in detail in the article “Smooth Nets”.

Next chapter

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set seine

The invention relates to the field of industrial fishing and can be used for commercial fishing in the coastal zone. The set seine contains a central cable, a guide wing made of netting, a frame and two traps, each of which has a lifting road with openings, an inlet and a cage. The central cable, the guide wing and the frame are mounted on the rebounds and unfastened by guy wires with anchors. Traps are mounted on the frame opposite to each other, and a guide wing is installed on the central cable. The main and additional traps have two pairs of entrances formed from the side of the coast and the sea, and the guide wing has openings at the end. EFFECT: increase in the fishing capacity of the fixed seine by increasing the fishing area. 1 ill.

The invention relates to the field of industrial fishing and can be used for commercial fishing in the coastal zone.

Fishing with fixed nets in some areas is a rather complex problem that has not been solved so far. On the one hand, the problem arises due to the bottom relief, where the seine is set up - the relief is not the same - it is difficult to set the seine to the optimal depth, it can cling to the relief and break when the sea is rough. On the other hand, the design of seines mainly provides for entry into the trap only from the side of the shore, which does not allow you to collect a large catch, because. the fish that comes from the sea goes back to the sea.

In addition, due to low storm resistance, in conditions of heavy seas or storms, seines become tangled, washed ashore and become completely unusable.

Thus, at the moment, the level of development of technology and the technology of setting fixed seines in the conditions of commercial fishing are still far from perfect.

Known set seine, including a guide wing, a yard with openers, a lift road and a cage equipped with a distributed buoyancy along the upper selection. Along the top line, the seine and cage are additionally equipped with a system of variable buoyancy blocks, which are evenly distributed along the top line and along the outer frame of the net and are connected to the wave compressor through the receiver. The net is attached to the ground with dead anchors by means of inclined braces (p. RF No. 2138161, IPC A01K 69/00, publ. 1999).

But despite the classical level of performance of the specified fishing gear, the following disadvantages can be noted: the net has a low productivity, because to completely fill the seine with fish, a rather long time is needed, since the seine has one entrance, which provides for the wait-and-see position of the fishermen to fill the fishing gear and, consequently, a certain loss of working time.

Known hanging seine, including a trap with a bottom and an inlet made in the form of a slot and equipped with a lifting curtain. The trap includes a lifting road and is additionally equipped with a rectangular frame, unfastened by guys with anchors, while two guide wings are attached to the narrow side of the trap, equipped with rebounds, one of which is two times shorter than the other (p. RF No. 2219768, MPK А01K 69/00, published December 27, 2003).

The disadvantage of the known invention is the presence of one entrance to the trap, which reduces the permeability of fish per unit of time and, consequently, reduces the efficiency of fishing.

In addition, noting the small size of the well-known seine as its advantage, we can say that this is also its disadvantage, since such a seine has a low production capacity due to the fact that after filling the seine, the fishing process is suspended for pouring fish, i.e. lost time to unload the catch.

Moreover, a small number of anchors and weights does not allow working with such a seine in conditions of high seas, because. it can be unanchored and carried away by the current.

A classic set seine is known, including a central cable, a wing made of a net cloth planted on rebounds, and a trap containing several net chambers - yards and cages. The net walls of the yard direct the fish to the cage, where the catch is concentrated. At the entrance to the trap there are openings formed by vertical converging net walls, designed to guide the fish into the trap. The entrance consists of a net tray that rises from the bottom almost to the surface of the water - a lift road ending with a pouring device (watering can). The trap is suspended from the frame. The central cable, frame and trap are secured with a bracing system. The net is attached to the ground with dead anchors by means of inclined braces. (Melnikov V.N. The device of fishing gear and the technology of fish extraction, M., Agropromizdat, 1991, pp. 127-133).

The disadvantage of the known fishing gear is the low production capacity of the seine.

The closest analogue of the claimed invention is a set seine containing a central cable, a guide wing made of a net fabric, a frame, a main and an additional trap, each of which has a lifting road with openings, an inlet and a net, with the central cable, the guide wing and the frame set on rebounds and unfastened with guy lines with anchors, while the traps are installed on the frame opposite to each other, and a guide wing is installed on the central cable (Andreev N.N. "Handbook of fishing gear, netting materials and fishing equipment", Moscow, Pishchepromizdat, 1962 , pp. 227-230).

The disadvantage of the invention is the presence of one entrance to the trap. This reduces the productivity of the seine, because. the fish enters the seine from one side and a certain waiting time is required to fill the seine.

The objective of the invention is to increase the production capacity of the seine, as well as to reduce the fishing time by ensuring the continuity of the process.

The technical result is an increase in the fishing capacity of the fixed seine by increasing the fishing area.

To achieve the technical result, a set seine containing a central cable, a guide wing made of netting, a frame and two traps, each of which has a lifting road with openings, an inlet and a cage, the traps (main and additional) are equipped with two pairs of entrances formed by from the side of the coast and the sea, and the guide wing has openings at the end.

Supplying the seine with additional openings makes it possible to form two pairs of entrances, which makes it possible for fish to enter both from the side of the sea and from the shore, and this, in turn, contributes to the speedy filling of the seine and an increase in the volume of fish catch, which leads to the achievement of a technical result.

The drawing shows the device in working position, general form, view from above.

The set seine includes a central cable 1, a frame 2 and traps 3 mounted on the frame 2 opposite to each other. Each trap contains a lifting road 4 equipped with 5 openers, a watering can 6 and a bulkhead cage 7. Openers 8 are installed in the middle, perpendicular to the central cable 1, forming entrances 9 to traps 3.

The central cable 1 and the frame 2 are mounted on rebounds 16 and equipped with 10 kukhtyl and 11 overlays to keep them afloat. To unfasten the frame and the central cable along their perimeter, braces 12 with anchors 13 are installed for attaching the seine to the ground. To guide the fish into the trap, a guide wing 14 is installed on the central cable 1, made of a net fabric and containing a flap 15 at the end.

The set net works as follows.

To set up a seine, first install the central cable 1 with the guide wing 14. Then install the 15 openers and the frame 2. Attach the traps 3 to the frame 2 and hang the openers 8.

In the process of fishing, the fish that comes from the sea passes along the guide wing 14, passes through the entrances 9, meets on its way the openings 8, which orient the school along the openings 5 to the trap 3. The fish from the trap 3 are prevented by the openings 5, which set at an angle to the inlet to the trap. Fish along the lifting road 4, then through the watering can 6 enters the bulkhead cage 7, where it is concentrated. According to the accumulation of fish, without stopping the fishing process, either a floating cage or any vehicle where the catch is poured is moored to the cage 7.

If the fish moving along the guide wing 14 from the sea tries to go back to the sea, then the 15 openers do not allow it to deviate to the side, they orient the fish along the guide wing 14 in the opposite direction, driving it into traps 3.

A set seine containing a central cable, a guide wing made of netting, a frame and two traps, each of which has a lifting road with openings, an inlet and a cage, the central cable, the guide wing and the frame are planted on the rebounds and unfastened by guys with anchors , while the traps are mounted on the frame opposite to each other, and a guide wing is installed on the central cable, characterized in that the main and additional traps have two pairs of inputs formed from the coast and the sea, and the guide wing has an opening at the end.

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The set seine, as they say in books, refers to "passive fishing gear", i.e., after it is installed, it "catches fish itself." The principle of operation is based on using the property of salmon to return to their native river after sea feeding. At the beginning of summer, the salmon dispersed in the places of the sea zhora begins to stray into schools, and foolishly rush to their rivers. It is still not really known what kind of GPS fish use, but the rivers where, who was born, salmon are found thousands of kilometers away.

When approaching their native shores and in search of their own river, salmon herds nestle against the coastline - this is where they are met with fixed nets. Along the coast of Kamchatka, if memory serves, "cut" about 400 sites for the installation of sea seines. But, as in any fishing - plots to plots, a lot of strife ... Naturally, the most "delicious" places are near the mouths of the rivers - there the fish will never pass by. However, it is forbidden to set a net closer than 2 km to the mouth, and the distance between the nets must be at least 2 km.

The seine itself is structurally a “wing” (a wall made of a net extending perpendicularly from the coast into the sea for about 1 km) and “traps” at the marine end of the wing (systems of the “nipple” type - a labyrinth with narrow entrances and walls and a bottom from a continuous network with a mesh of about 30 mm).

The principle of operation is nauseatingly simple - a salmon walking along the coast stumbles upon an obstacle (wing), starts to bypass it ... runs into traps and that's it ... All that remains is to “sort out” the seine, drive the fish to one end and “pour” it into the “slot” ( a barge without a bottom, covered with a net so that the fish live there longer) or a "cage" (a blank fence from the same net adjacent to the trap). In the slots in tow, the fish is handed over for processing - to their factory on the shore, or "at sea" to fish processing vessels. The steamboat, again, can be its own (master's), or left, where the fish is handed over under the contract. Depending on the "yield", the price of the issue ranges from 60/40 (60% of the proceeds from fish to "getters" and 40% to "receivers"), to the opposite - 40/60 (this is when fish are like dirt, and there is nowhere to put them ). It is considered fair if 50/50%.

Below, some nasty photos from such fishing in the previous year:
View of the seine from the slot from the side of the cage. The iron boat on the right is a "sabunka" - used to monitor the situation (whether the fish has entered) and minor repairs of nets. In the background is a "bulkhead" on which a team of fishermen sorts out a seine (drives the fish to the dead end).

Bulkhead seine at the stage of completion.

Bulkhead completed and preparation for "filling" the slot.

Slot filling.

The hole is filled.

The boss leads the process.

Transportation of the slot to the receiving and processing vessel (floating base Sodruzhestvo)

View of the boat and the slot from the deck of the mother ship.

View of the deck from the forward superstructure.

The simplicity of the “theory” of such fishing does not at all guarantee the same in “practice” ... Only the installation of a fixed net requires 2-3 weeks (subject to good weather and calm seas). In addition to the delivery and “bringing into working condition” of the shmurdyuk itself (nets, cables, ends, buoys, etc.), it is required to dig up and prepare in the fishing area about 2000 (two thousand !!!) sandbags for loading guy wires, with which the whole structure of the seine is fixed ... Take out from the shore into the sea and "drown" these same bags, "bundles" of no more than 50 pieces. at a time, because if there is more, then the ship may capsize. And such cases, unfortunately, were ...

The net itself needs not only to be installed, but also set up, almost like a piano - to adjust the dimensions, height and dimensions of the “passages” and all that. Like any “delicate matter”, setting up a seine requires not a hefty skill, if not talent ... Therefore, good foremen responsible for setting a seine and fishing are highly valued and well paid.

However, to catch a lot of fish, although this is a necessary condition, it is not yet sufficient for successful fishing - all fish must be well attached (processed at your own factory or handed over to a receiver on favorable terms).

Only in order to “recapture” the costs of setting up a seine and at least pay the fishermen something, you need to catch at least 200 tons of salmon. But in general, the "performance" of such a seine, with good conditions(approaches of fish, calm weather, etc.), allows you to take 1000 or even more tons for Putin.

And, lo and behold... A team approached Kolpakov, with whom I was supposed to work under a scientific quota. At first glance, the fishermen, like fishermen, are all hardened in words (cooler, only eggs). The brigadier, however, confused a little - he was young ... and somehow weak with charisma ... But the men arrived on a very dexterous MRS-80 (small fishing seiner). They also lived on it (7 people in the cockpit and 6 in the hold adapted for life), they also served the net.
Amenities from the stern, dining room on the cover of the hold.

Based in the estuary of the river. Mikhail Nikolaevich often looked at the "light" and whites from the seal's liver (pictured below)

Our site under the seine is the most "chocolate" - the first from the mouth of the river. Kolpakov to the north. The men put the central and frame under the seine ahead of time - it remains only to hang the "rags" (nets), which they did without problems in a few days. The weather whispered - the sea, like a mirror.

As soon as the seine net was set, the fish immediately went. There was no blockage yet, but in a couple of days they drove 30 tons into the cage. But with the delivery of the catch, there was a strain ... The vessel, with which an agreement on joint work was concluded in advance, has not yet approached the fishing area ...

Live fish in a net can normally “live” for 2-3 days, and if it is not “cleaned up”, then it dies and falls to the bottom, tightly piling the net with its corpses. If this happens, it's easier to cut the traps and re-sew than to manually try to throw it out.

There was nowhere else to “pull” with the delivery of fish, and the representative of the company decided to drag the slot to Sobolevo, or rather, to the mouth of the river. Vorovskaya (the company has its own fish processing plant in Sobolevo). And the way by sea is only from the mouth of the river. Kolpakova to Vorovskaya is about 60 km ... As a rule, such slots are not dragged further than 3-5 km ... There is a wave in the sea ... the fish will snort, wash ... Again, speed - with a slot on a leash, the course is no more than 3-4 knots.

Since there was nowhere to go, we went to Sobolevo. We set off in the morning and by 7 pm we approached the mouth of Vorovskaya ... but you can’t go in - the tide is out. For another three hours they hung out in front of the mouth, and when the water “approached”, they set off to enter. By this time, twilight had already thickened, but in principle, there was more or less visibility.

Overcoming the elastic countercurrent of the fairway, our MRS with a slot on the leash was slowly drawn into the river. And when it already seemed that everything - the mouths had passed, the ship, trembling from the strain of all the horsepower, was shaken by a strong side impact (almost fell off its feet) ... !!!?

While in bewilderment they tried to find out the cause of the underwater "hook on the right", men began to jump out of the hold and throw their mattresses and belongings from there onto the deck. It turned out that a hole (the size of a boot) was formed from the impact, with which outboard water whipped with terrible force !!!
The hold before our eyes was filling with water, in which firewood, socks, clothes were floating mixed up ... In less than a few minutes, the men in the hold were already fussing in waist-deep water ... and she was arriving ... !!!

Attempts to push the hole with mattresses and rags did not give any results, because because of the bunks and the inner lining it was impossible to get there ...

Fortunately, a 10 cm hole “did not get” the adjacent engine room and the ship remained on the move. They managed to call for help on the radio in time. An MPC-150 jumped up from a nearby pier and unfastened our slot with fish. Light and at maximum speed, they rushed to the shore. And when it was already possible to touch the water from the deck with your hand - Thank God, we ran aground.
It's gone...

PS. I apologize for the quality of the photo - camera"

UDK 639.2.081.117

A.A. Grachev, D.A. Grachev

Astrakhan State Technical University, 414025, Astrakhan, st. Tatishcheva, 16

A NEW METHOD OF INSTALLING A SET WING

A method is proposed for installing the wings of a set seine along a broken line, which has significant advantages over the traditional method for installing a wing in a straight line. A mathematical model of the process of guiding fish by the sectional wing of large traps installed along a broken line has been developed. The results of calculations of angles for various options for installing wings, including a curvilinear shape, are given.

Key words: fixed seine, wing, mathematical model, optimization.

A.A. Grachev, D.A. Grachev NEW WAY OF INSTALLATION OF MAIN LEADER NET

A method of the stationary net leaders" installation by a broken line has the significant advantages over the traditional way of installation by a straight line. A mathematical model of the areas of the large fish sectional leader traps set by a broken line shows the calculation results of optimization setting angles for different installation options of the leaders, significantly increases the efficiency by optimizing the gear setting angles sectional leaders set by a broken line.

Keywords: stationary uncovered pound net (set-net), main leader net, mathematical model, optimization

Introduction

F.I. Baranov laid the foundations for the theory of trapping, having considered the principle of operation of traps, the theory of the wing, the foundations of the theory of inlets, gave a qualitative justification for some indicators of the elements of these fishing gear, etc.

At present, for the analysis and substantiation of indicators of fishing with traps, mathematical models are often used to assess the productivity of fishing through the fished volume and the probability of fish leaving the fishing zone in various ways.

Purpose and objectives of the study

The most important from the point of view of fishing efficiency is the first stage of the process of detaining (capturing) fish by the wing and directing them to the entrance to the trap.

At present, in domestic practice, the wings of large traps are set strictly straight, mainly at right angles to the direction of the coastline, in order to provide the largest fished area.

Modern studies of fish behavior using sonar and underwater observations show that a significant proportion of fish (up to 50%) move in the opposite direction from the trap and leave the fishing area, reducing its effectiveness.

The ratio between the number of fish heading in the direction of the trap and in the opposite direction depends mainly on the direction of installation of the wing in relation to the direction of the fish - the "fish route".

In this regard, it is advisable to determine the optimal wing installation angles depending on various fishing indicators, including the characteristics of the external environment, the type of fish and the nature of their behavior and distribution, etc.

Mathematical modeling of the process of directing fish with a straight wing

M.I. Gurevich proposed a hypothesis about the analogy of the movement of a school of fish with the movement of a liquid jet running onto an oblique wall, according to which the probability of the direction of the fish by the wing towards the trap is represented by a dependence of the form

P(a)=--->(1)

_ ". . 1 - cosa and in the opposite direction: p (a) =---, (2)

where a - angle of installation of the wing to the "fish route", deg.

Given the efficiency of this hypothesis in relation to some fish species and fishing conditions studied in the works, it is possible to solve the problem of optimizing the angle of installation of the wing of traps in order to increase the efficiency of fishing.

It is of interest to optimize the choice of the angle of installation of the wing with one trap at the end to the "fish route" at a distance from the coast in waters with equal depths. For simplicity of calculations, the probability of fish escaping through the net and away from the wing can be neglected. In this case, as we have shown in , the relative proportion of fish Q(a, L) directed by the wing to the entrance to the trap from the angle of its installation to the direction of the “fish route” and the wing length L is equal to

k[(1 + cosa) (-kgT \ ■ Q (a, L) \u003d - "- x (e kT) x sin a. (3)

On fig. Figure 1 shows the results of calculating the dependence of the relative proportion of fish caught and directed by the wing to the entrance to the trap, on the angle of its installation a to the direction of the "fish route" and the length of the wing according to formula (3) using the Mathsay program.

/U" /■/ // v\

r tí ■/ / \ 4 \

ft É 1 í ! i / ? h-L\X

/1 / 1" / ■■" }//. ■ ■" 4 > \

Rice. Fig. 1. Dependence of the relative proportion of fish Q caught and directed by the wing to the entrance to the trap on the angle of its installation a to the direction of the "fish route" and on the length of the wing L, at L = 5-1500 m; kL = 0.001; to" != 1 Fig. 1. Dependence of a relative share of fishes Q delayed and directed by a wing to an

entrance to a playground from a corner of its installation and to the direction of "a fish route" and from wing length L: L = 5-1500 m; kL = 0.001; to 1= 1

It is shown that the largest proportion of fish directed by the wing into the trap corresponds to an angle of ~ 60° with respect to the “fish route” and decreases with increasing wing length.

In the Volga-Caspian basin, small traps (secrets, vents) are traditionally set with the wing “on the move” of the fish, i.e. at an angle of 50-70°. Large traps for catching salmon fish in the coastal zone of the Far East and Kamchatka, off the coast of Dagestan, Azerbaijan and Iran in the Caspian Sea are mainly set at an angle of 900.

Mathematical modeling of the process of guiding fish by a curved wing

Taking into account the results of previous studies and the experience of practical application of schemes for setting small traps "on the move", it seems appropriate to increase the efficiency of fishing by installing the wings of large traps not in a straight line, but in the form of a broken line with a decrease (or increase) in the installation angle of the section to the "fish route" from the coastal to the rod. At the same time, the number of wing sections can be more than two, and the installation angle of the initial (shore) section and the angle between adjacent sections can be changed and optimized depending on the fishing conditions.

This proposal is supported by experimental data, which showed that the efficiency of a curved wing is higher than a straight one, while the proportion of fish caught in a trap was 46%, and for a straight wing it was much lower (23%).

Let b be the length of the wing, k be the coefficient that takes into account the proportion of fish walking along the wing that will reach the entrance to the trap, a is the initial angle of the wing (coastal section), n is the number of wing sections, r is the number of the section, r is the law fish density distribution, b is the angle between adjacent sections, b0 is the optimal angle between adjacent sections.

Let us determine the relative proportion of fish Q(b) directed by the sectional wing to the entrance to the trap, taking into account that each section is set at a different angle to the “fish route” and directs fish into the trap with different probability as a sum of probabilities:

e ~ kbz (/> m

As an example, we set the initial parameters in the form of the following values: a = 90°, n = 3, with a uniform distribution of fish density r(x) = 1. For simplicity of calculation, we take the wing length b = 1 and the coefficient k = 0.1. The solution of equation (4) makes it possible to optimize the angle between the sections with the value b0 = 17.745°; at the same time, the relative proportion of fish directed by three sections of the wing into the trap is maximum and equals Q(b) = 0.532, or 53.2%. A similar wing installed in a straight line at an angle of 90° gives the value Q(b) = 45.2%.

On fig. Figure 2 shows an example of optimizing the installation angle of a three-section wing according to formula (4) using the Mathcad program.

Significantly up to 0.581, or by another 9%, the proportion of fish directed by a three-section wing increases, with a decrease in the initial installation angle of the coastal section to 70 ° compared to the traditional scheme. In this case, it is necessary to install the second and third sections at angles of 64 and 58°, respectively, with an adjacent angle between the sections of 6°. At the same time, the increase in fishing efficiency is 28.5% compared to the traditional scheme. Calculations by formula (4) show that for

two-section wing, if the initial section is installed at a traditional angle of 90°, then the second section must be installed at an angle of 60°. In this case, the proportion of fish sent to the trap will increase by 15%. The choice of installation option depends on the characteristics of the water area and the nature of the distribution and behavior of fish in the zone of action of the wing. The proposed calculation method makes it possible to take into account these features to a large extent and optimize the wing installation scheme for specific fishing conditions.

On fig. Figure 3 shows the possible schemes for installing the wings of the fixed seines with the calculated indicators of the relative proportion of fish directed by the wings to the entrance to the trap. With an increase in the number of sections, the installation of the wing is carried out almost along a curve (dashed line). The curvilinear installation with an initial installation angle of 90° increases the efficiency of the wing by 20.6% compared to the traditional one. With an initial installation angle a less than 60° (upper diagram), subsequent sections are installed under high angle to the direction of the “fish route”, since b0 takes negative values.

Rice. Fig. 2. Dependence of the relative proportion of fish Q(b), directed by a three-section wing to the entrance to the trap, on the angle between the sections b0 2. Dependence of a relative share of fishes of Q(b), a directed three section main leader net to an entrance to a playground, from a corner between the sections b0

Rice. Fig. 3. Values of the relative proportions of fish directed by wings to the entrance to the trap for various installation schemes 3. Values of relative shares of the fishes directed by wings to an entrance to a trap for various schemes of installation

The proposed installation schemes will improve the storm resistance of the seines, since the rod sections of the wing experience less hydrodynamic resistance during storm currents. On the other hand, the vortex trails (vortex sound) created by the flow when flowing around the elements of the wing of the set seine as the angle decreases, will change in the direction of decreasing sound intensity and

increasing frequencies, helping to reduce the distance of the response of the fish to the wing. In this case, the design of the yard will need to be changed taking into account the angle of installation of the last section of the wing. In addition, a gradual decrease in the angle of installation of the wing will make the movement of fish along it more stable and will affect the decrease in the probability of fish leaving the wing, depending on the length of the wing.

The proposed calculation method can be used both when fish approach from one side of the wing and from the other, and the total proportion of fish is determined by summation, taking into account the ratio of the proportions of fish approaching from each side.

The curvilinear form of the installation can be used not only for wings, but also for yard openers and other elements of the set nets, which will increase the likelihood of fish entering the traps and making it difficult to exit.

It is advisable to conduct a set of experimental studies under field conditions to refine the adjustment coefficients included in the proposed dependence for estimating the relative proportion of fish directed by the wing towards the trap, for various ways installation of wings of fixed nets, as well as to test a trap with curved elements.

A method is proposed for installing the wings of a fixed seine along a broken line, which has significant advantages over the traditional straight line.

A mathematical model of the process of guiding fish with a sectional wing installed along a broken line to the entrance to the trap has been developed, options for calculating the optimization of installation angles have been presented.

A significant increase in fishing efficiency is shown by optimizing the installation angles of sectional wings along a broken line, including along a curve.

Bibliography

1. Baranov F.I. Selected works. T. 1. Technique of industrial fishing. - M.: Pishch. prom-st, 1969. - 719 p.

2. Melnikov V.N. Biotechnical substantiation of indicators of tools and methods of industrial fishing. - M.: Pishch. prom-st, 1979. - 375 p.

3. Melnikov V.N., Khanipur A.A. Mathematical model of fishing with fixed nets // Tr. International Conf. dedicated to the memory of prof. V.N. Voynikanis-Mirsky. - Astrakhan: AGTU, 2000. - S. 63-64.

4. Grachev A.A., Melnikov V.N. Development and application of mathematical models to improve the efficiency of fishing: a review. inform. VNIERKh. Ser. Industrial fishing. - 2002. - Issue. 1. - 50 s.

5. Grachev A.A., Melnikov V.N. Commercial and environmental problems of increasing the efficiency of the use of commercial fish stocks. - Astrakhan: Ed. house "Astrakhan University", 2006. - 207 p.

6. Melnikov V.N. General mathematical models of productivity of fishing with fixed nets and small traps // Vestn. ASTU. Ser. Pisces. household - 2010. - No. 2. - S. 25-33.

7. Melnikov A.V., Grachev A.A. Substantiation of indicators of the net fabric of fixed nets // Vestn. ASTU. Ser. Pisces. household - 2010. - No. 2. - S. 34-45.

8. Grachev A.A. Estimation of catchability of a trap taking into account the time of stagnation // Vestn. ASTU. Ser. Pisces. household - 2012. - No. 1. - S. 36-43.

9. Grachev A.A. Evaluation of indicators of the probability of detention and direction of fish by the wing of the trap // Vestn. ASTU. Ser. Pisces. household - 2012. - No. 1. - S. 30-35.

10. Inoue Y and, Arimoto T. Scanning sonar surveyon the capturing process of trap nets. Proc. world pump. fish. Gear and Fish. Vessel Design. - 1989. - P. 417.421. St. John's, Newfoundland: Marine Institute

11. Gurevich M.I. On oblique running of fish onto a net partition // Ryb. household -1963. - No. 9. - S. 47.

12. Suzuki M. A fundamental study on fish movement in response to set nets and the function of the fishing gear. J/Tokyo Univ. fish. - 1971. - 57 (2-2). - P. 95-171.

13. Inoue Y. Effect of Blocking and Leading Fish School by Set-net Leader // Bull. Japan. soc. sci. fish. - 1987. - 53(7). - R. 1135-1140.

14. Inoue Y. Fish Behavior in the Capturing Process of the One-trapped and the Two trapped Set-net // Bull. Japan. soc. sci. fish. - 1986. - 53(10). - R. 1739-1744.

Grachev Dmitry Alexandrovich, e-mail: [email protected].

How fish are caught in pond and lake fish farming

In the practice of fishery development of inland water bodies, including water bodies for complex purposes (VKN), various tools are used to catch fish, but active fishing means are preferred.

Regardless of the methods and gear used reservoirs must first be prepared for fishing:

carefully examine the bed and banks;
clear the water area from floating objects, trees and shrubs protruding above the water or connected with the ground;
remove alloys;
clear the bottom of sunken objects; align the bed;
perform other tasks depending on specific conditions.

According to the principle of action fishing gear divided into three groups.

The first one is called “enveloping” networks. Their principle of operation is based on the fact that the fish gets stuck, or “enclosed”, trying to pass through the nets installed in the form of a wall in the way of its course. The net cloth in such tools is made of a thin thread and either cuts into the body of the fish or confuses it. In VKN and on small lakes, fixed nets are used, which remain motionless in one place during the fishing process. Their catchability is low and in comparison with other tools does not exceed 14-15%.
Fixed networks are widespread. They catch different types of fish. In ponds, single nets are used, and for catching larger reservoirs, the nets are connected in series into a long wall, the so-called net order.

staked network(Fig.) is a rectangular canvas, planted on the upper and lower pick-ups and sometimes on the side veins.

: simple; b - cutting.

The rebounds are made longer than the planted web of the network in such a way that free ends 0.5-0.8 m long protrude from each of its sides. These ends, called priukhs, are designed to connect the networks in a net order. Sometimes priukhs are made in the form of loops. Nets are planted with a coefficient of 0.5! Floats made of polystyrene (melt) are attached to the upper selection, sinkers are attached to the lower one. The number of those and others depends on whether the network will work afloat or will be deepened.
According to the device, the fixed nets are simple and “thin”, sometimes they are called two- and three-walled, depending on the number of net walls.

For fishing areas with a depth of 1.5-2 m, the nets are installed on poles, with an increase in depth - on anchors. The first net is tied up in such a way that the lower end of the pole is at a distance equal to the depth of its driving into the ground from the lower end of the pole, and the upper one is tied up depending on the height of the net. The other end of the network is tied in the same way to the second pole, the lugs of the first end of the second network are attached to it, etc. The prepared networks are loaded into the boat and taken to the installation site.
On poles, they are usually installed for one night or a day, but sometimes for a longer time. In the first case, the catch is chosen simultaneously with the removal of the net order, and in the second, they are sorted out at least twice a day, removing the caught fish.

Even more common is the installation of fixed orders at anchors both in shallow water and in depth. Stones, bricks and other improvised materials are used as anchors.

The second group consists of screening tools in the form of a net wall of various shapes. Having swept over a part of the reservoir, the tackle is sunk ashore or on a watercraft. Water passes freely through the meshes, the fish lingers, but does not get tangled or bundled up, but remains on the canvas or rolls into a bobbin. Fishing in these cases is undesirable and even harmful, as it slows down the work and reduces the productivity of the fishermen. Therefore, netting is made from coarser threads and with a finer mesh than that of nets. The most widely used of this group of tools were cast nets. The seine is considered optimal with a length of at least 1/3 of the perimeter of the reservoir.
A throwing equal-winged net (figure below) consists of two identical wings, two drives and a bobbin.

: 1 - wing; 2 - drive; 3 - skein 4 - outlet (shirt) skein; 5 - upper selection; 6 - lower burr; 7 - floats; 8 - weights; 9 - nag; 10 - bridle; 11 - edge.

The wings are designed to cover the fished area of the water area and represent the longest part of the seine. They are made from a relatively light and large-mesh case, and sometimes composite: canvases from a heavier fine-mesh case are placed in the center. This distribution of delhi is explained by the behavior of the fish: at the beginning of the seine operation, it does not seek to leave the swept area, but as it sinks, it tries to leave the seine. This is prevented by the part of the wing remaining in the water.
The height of the wings to the ends (nags) is reduced so that when they sink, they are the first to go ashore.
The drives are used to guide the fish into the motna. They are made from a thicker thread and a small-mesh deli 20-40 m long and sewn with a bobbin.

Nets are planted on rebounds with a coefficient of 0.5. A melt is attached to the top, a load is attached to the bottom, and poles or nags are attached to the side edges. They straighten the ends of the seine, preventing the rebounds from folding when sinking. Ropes are tied to the nags, ropes are pulled for them.
Catching marketable fish from the VKN is the most difficult and time-consuming task. The greatest effect is given by throwing seines of large sizes. Their catchability increases in proportion to the area of the wrapped space, which is confirmed by the experience of total fishing of small lakes in the Novgorod, Pskov and Leningrad regions, as well as some VKN of the Stavropol Territory.

In this case, it is recommended that the seine is 1.5 times longer than the maximum width of the reservoir and 5-6 m high with flared wings.

the first is equipped with a stationary engine with a capacity of 11 liters. With. and a winch driven by a Vyatka motor;
the second is a seine net (750 m long seine is laid in the stern of the boat, the upper line is laid in loops, the lower line is in rings);
the third is equipped with a 1000 m long cut (cable with a diameter of 30 mm);
the fourth has an edge and a winch (a truss with rollers for normal cable feeding is installed in the bow); the fifth is intended for the transportation of caught fish.

: 1 - edge; 2 - wing (goes from the shore); 3 - motna; 4 - fugitive wing (larger); 5 - edge; 6 - non-water; 7 - motor boat.

: A, B, C - venteri; G - fixed seine.

To increase catchability, the barrel is equipped with wings from 5 to 200 m long. They block the fish from the bottom to the surface and direct it into the vent. Several additional small wings, the so-called openers, serve the same purpose.
Fish caught in the vent accumulate and remain in it. During inspection, small-sized venteri are taken out of the water entirely, and for large ones, only a cod, the end of which is unraveled and the fish is shaken out into the boat.