What is drift-nets, drift-net fishing

Drift fishing is fishing, which is carried out by drifters - fishing vessels. The ship drifts with the current and the wind along with a very long network, the so-called drift-net order, or floating networks, forming a single system. The length of the networks can reach 50 km. These nets catch moving fish. The need for drift-nets has arisen in connection with the need to harvest some species of fish that are kept sparingly. In this way, tuna fishing is carried out, salmon, mackerel and herring are mined.

Network Features

Driftnet (or flowing) networks are a web that the fish does not regard as a barrier, so it tightens the mesh tightly, tightly entangling them without being able to escape. Rectangular individual networks with a height of 10-12 m and a length of 30 meters are connected to each other in a single drift-net order, which can be based on a rope-leader, and buoys and floats support this system at a given depth. Drift networks are used for the commercial extraction of fish from drifters.

Materials used

The catchability of tackles depends on many factors, including the material and thickness of the thread, the size of the cells, the coloring, and the landing of the cloth on the rebounds. If previously used vegetable threads, including cotton from twisted yarn, now the most frequently used are durable and catchy fishing nylon nylon, as well as nylon, amilane and similar of artificial fibers.

High efficiency is demonstrated by fishing nets from monofilament (fishing line), the so-called venation. The main advantage of these gears is their transparency. Even in daylight, the catchability in clear water is very high, while competently colored networks of other materials can scare away the fish. In addition, they have higher stiffness than twisted yarns, which keeps mice stretched, does not allow networks to become entangled and contaminated. Although the rigidity slightly complicates the work with them and increases the volume, requiring more space on the deck.

Constructive types of networks

In their structure, the devices for fishing may be single-walled gill, double-walled or tri-walled. The last two species are also called "knapsacks". The most effective are three-walled fishing net, consisting of three netting. Outside there are large-lined canvases, called rye (rye, rye), and in the middle there is a smaller part (del). All three canvases are planted in one set, but the fragment has a long length and is located between the outer layers with considerable slack. Passing through the cut, the fish gets entangled in the particle, getting into the net bag. Double-walled consists of two canvases with different sizes of cells and are effective in the case when it is known exactly which side the fish is coming from.

For drift-net fishing fishing nets are most often used from monofilament or from nylon monofilament. The rebounds are also taken nylon. Three-walled smooth networks are most effective.

Types of drifter orders

Networks can connect to each other in many ways. There are three basic types: simple, with top or bottom leader. In the coastal strip, small simple orders can be used, but in the open sea a more reliable construction is needed, therefore orders with leaders that ensure order integrity and increase reliability are used.

Simple order

For a small drift-net order, sometimes several separate networks are connected in series with each other by lower and upper ears. So get a simple drift-net order. It is used in lakes and marine coastal areas by small vessels. Most often it includes only 15-20 networks, but when they take more, they generally do not exceed 1-1.5 km.

The buoyed streamers are attached buoys, which keep the order afloat. The required horizon is set by adjusting the length of the streamer lines. From the bottom, the net is heavier, placing the load in the lower selection. On both sides of the order there is also effort. At the front, they are fastened with a stop end - a rope that goes directly to the ship, and at the rear they connect with the tail end - a rope fixed to the lighthouse. This lighthouse (a lantern or a pendant fixed to a buoy with weighting) shows where the order ends.

Organize this order easily, but for long networks, and even more so for use in the high seas, it does not fit. The tension of the networks during the drift is very high, so with such an organization, order can be torn from the vessel or it will be destroyed.

Appointment of the leader

To significantly reduce the risk of breakage, use the so-called leader - a thick rope, to which the order is attached throughout. Fishing involves pooling up to 100-150 networks. Tension during drift is a reliable leader, not the networks themselves. Separate networks are attached not only to each other, but also to the leader, which also strengthens the design.

The leader himself can be divided into three parts: the leader himself, the stop (parking) end for connection to the ship and the wax-up end for securing the lighthouse. It turns out that the leader is attached to the ship, which keeps the network. The parking end is made as durable as possible. Its length can reach 200-500 m, which depends not only on the depth to which the order is submerged, but also on the state of the sea and the strength of the wind.

When selecting networks, the thrust is carried out for the leader. This allows you to mechanize the production process. In addition, machines are used that control the tension of the leader, if necessary, releasing it to reduce excess tension.

Features of the leader

Depending on the fishing technique and the type of vessel itself, the required length of the streamer lines is established in order to conveniently select drift-nets: the leader is chosen through the mulgoger, and the network must reach a certain place on the board, the lines should just provide the required distance. On small vessels it is only 1.5-2 meters, and on large vessels it can reach 10 m.

Due to the fact that the tension of the leader as you move away from the ship to the beacon decreases, the leader is often made composite, reducing the thickness of the rope. In addition, this reduces the cost of order and reduces the weight of the order. But in order not to appear sagging closer to the end of the network due to reduced tension, sometimes to the lighthouse add floating anchors or change distances between buoys.

Order with the lower leader

To organize order with the lower leader, separate drift-nets are combined into a single whole for the upper and lower spirits, but the leader goes all the way through the networks. It is connected to the networks by the leader lines with the help of fast-detachable assemblies. On the float, the order is held by buoys, which are fastened to streamers at the junction points of the nets or to the upper selection. The depth of the networks depends on the length of the streamer lines. Additional cargo at the bottom is not required, since the leader himself serves as a load, stretching the networks.

Apply this order for shallow depths, immersing the network at 30-40 meters. It is convenient to operate. For marking and selecting the order, you only have to work with leader lines, without the hassle of sinkers.

Order with the top leader

If it is necessary to fish at great depths, the order with the top leader is often applied. In this case, it passes over the networks. Buoyed streamer lines are attached to it, reaching a length of sometimes more than one hundred meters. Between each other the buoys are connected by a rope-conductor for convenience of sampling. Leader lines are connected with the top selection or the nets of the nets. On the lower rebounds have to add a load in the form of cast iron.

To work with such an order is more difficult than using the lower leader, since it is necessary to organize the load, and additional attention is required by the buoyant conductor. However, such drift-net fishing is a necessity for fishing at great depths. In this case, the lower leader can, upon sampling or even pulling, wind the net on himself, so it does not apply. In addition to the pluses of the top leader, you can also add dampening of jerks from the buoys, so the networks will be more quiet. The downside is the risk of detachment of the buoy itself on large waves.

In fact, sometimes different orders are used to determine exactly where a particular fish is. To do this, often create combined types of orders.

Harm from the use of drift-nets

In some regions, commercial fishing with the help of drift-nets is prohibited. So, do not apply it in the North Pacific to keep stocks of some species of fish. Large-scale drift-net fishing is prohibited by the UN General Assembly in the open waters of the World Ocean. Scientific fishing is allowed by such networks, but this possibility is often abused. While there is no complete ban on drift-net fishing, there are already established shorter terms and some restrictions on this type of fishery.

Drift nets often include marine mammals and seabirds that die. The figures are simply awesome. So, only in the Far East in the Russian economic zone because of this, over 100 thousand birds and 2.5 thousand mammals die each year. And the populations of salmonids themselves are shrinking.

Another serious threat is the attitude of the fishermen themselves. Often, sockeye salmon is produced the most valuable of salmon, while the rest of the fish, including sockeye salmon, other salmon, pink salmon and chum salmon are simply thrown overboard. Such re-sorting destroys an aimlessly huge amount of fish, which is a violation of the rules of fishing.