Carp is a dominant species in large surface waters. However, the carp belongs to the bottom fish and is sensitive to the net. When it touches the net, it can both drill through the net and turn to avoid the net. Therefore, the average catch rate of the gill net and the set net is very low. For a long time, catching fish has become a major problem for catching large lakes such as lakes and reservoirs. The author designed and installed a “skirt net†for Gutaixi Reservoir to carry out specialized catching experiments based on the experience of the single-layer gill net of Songhuahu Reservoir in northeast China and the single-layer gill net of Xinanjiang Reservoir in Zhejiang Province. Certain results.
"Skirt net" is also a single-layer gill net type, due to the use of different upper and lower levels of horizontal shrinkage coefficient, so that the traditional rectangular gill net mesh becomes a fan-shaped upper short segment, when the fan-shaped mesh is floating Under the effect of sinkers and buoys, when standing upright in a certain water layer, it is in a “skirt†type “∽†shape wavy, so it is called “skirt netâ€. When the carp encounters the “skirt net†to turn around, it is arrested by wavy net clothes, thorns, wraps, bags, and collusion. In addition, the “fishing net†material selection and assembly process highlights: “two fine†The technical characteristics of (fine wire mesh, fine upper and lower wire), "two light" (light weight of squat, light buoyancy), "large" (large float spacing), and "small size" (small horizontal shrinkage coefficient) make the net In the water body, it has good relaxation and softness and enhances the entangling performance. At the same time, according to the characteristics of the squid transforming the life of the water layer, by adjusting the length of the buoy rope, the net gear is accurately distributed in the center fishery where the squid is active. Greatly improved the catch rate. This article describes the fishing nets and fishing methods of “Skirt Net†as follows:
One, nets
1. Netting materials, specifications, and dosage:
(1) Net clothing: 12cm large head adopts 0.25 rubber wire, 1400 heads long, 35 heads high, heading 14cm adopts 0.3 glue wire length 1200 meshes, and 30 heads high. The coefficient of horizontal shrinkage is 0.3 in the outline, 0.38 in the outline, and 0.955 in the vertical shrinkage coefficient.
(2) Upper class: 2 roots, 0.25/38 polyethylene wire, 52m piercing length, and 58m assembly line.
(3) The following outlines: 2 roots, 0.25/38 polyethylene thread length 66m, and 0.25/33 polyethylene thread length 70m.
(4) Floats: 51, 8cm2cm2cm foam blocks.
(5) Shen Zi: 161, 25cm4cm2cm
2. Net equipment assembly:
The two types of net equipment assembly methods are basically the same. Now, only the mesh size of 14cm is described.
(1) on the assembly method: first with a length of 52m of the upper class (called wear class), through the length of the net mesh head, and then with a length of 58m another upper class (called assembly) loaded float, Each of the two upper thread heads shall be kept at a length of 1m (as a net string for fixing or splicing nets when the net is placed). From 1m onwards, 1 float shall be placed per meter, 3 mesh nets shall be placed on the float, and 2 shall be placed between the floats. Head. In order to prevent the float from falling off due to excessive force when closing the net, when tying the float, wear the knot without hitting the knot, and only use the assembly to put double knots near the ends of the float.
(2) Under the assembly method: 0.25/38 polyethylene wire as the wear outline, 0.25/33 polyethylene as the assembly, 1 sink per 40cm, 2 heads in Shenzhong, and the net between Shenzi is 5.5 heads, Shen Zai beat a knot again. At both ends of the sinker, a shallow slot is clamped with a vise so that it can be fastened tightly. Loading method with floats.
3. Affiliated fishing tackle:
(1) Buoys: Bubble floats with a buoyancy of 400g. Each net (50m long) with 2-3. The buoy rope also uses a 0.25/38 polyethylene wire, the length of which depends on the deepest layer of the net, but generally does not exceed 20m.
(2) Shen Shi: Generally, each working ship is equipped with 2-4 pieces of heavy stone weighing 2.5kg-5kg. Shen Shisheng can use yellow-brown ropes with a diameter of 0.6cm-0.8cm or 0.25/320 polyethylene ropes. The length of ropes for each sinker is 30m-50m.
(3) Net boat: It is a 1t-bit, 3.2m-long small fascia board.
two. Fisheries law
1. "Try Network":
The method of “trial network†is that each fishing team lays the nets in water layers of different depths in different fishing grounds, and then conducts statistics, analysis, summary, and determination according to the catch rate and the site of the Internet for each group. The orientation of the center of the fishery in this season's squid activity.
2. Release:
In general, each net boat is equipped with 20-30 nets (1000m-1500m length). The nets are stacked horizontally in the midship of the net boat. Shen Zigang is located in the direction of the bow and the float is in the direction of the rear cabin. The net work is carried out by two people. The front cabin is a rowing boat and the Shenzhuang Gang. One person is responsible for the piling, float class and buoy hanging. When the net boat arrives at the fishery, the people in the rear cabin will throw the sinking stone into the water first. After the sinking stone is in the end, the upper net rope is tied to the sinking rope, and then the rowing boat is placed on the net. With the progress of the net boat, the net gear Water from the right side of the shipboard. When the last mesh was put, the upper mesh string was tied to the other sinking stone and the stone was thrown into the water. Then check if the buoy is loose or if the buoy rope is fully spread.
The network deployment time is usually before the daily sunset, and the special circumstances are flexible.
3. Net collection:
First, the boat was moved to the sinking buoy at the downwind position, and the Shen Shi was pulled up to close the net. When the two received their nets, one person received a floater class in the rear cabin and was responsible for arranging the buoys and controlling the ships. One person received the sinker class in the fore cabin, and the catches were taken from the near places. If there are three people collecting nets, one person can pick up the nets in the middle cabin and specialize in taking the catches. In the net collection, the nets, buoys and all kinds of ropes should be clearly arranged so as to facilitate the next net release.
three. Question Discussion
1. Determine the length and height of the net:
The length of the gill net is mainly determined by the width of the fishery water area and the convenience of operation. The length of the general unit mesh is 15m-50m, but there is no uniform standard everywhere.
The height of the gill net is determined based on factors such as the depth of the fishery, the habits of the fishing object, and the habitat layer. Within the depth of the fish habitat water layer, the higher the height of the net, the larger the catch area and the higher the catch rate. The net height of a typical single-layer gill net is 1m-5m.
2. Mesh size determination:
The thorn-based single-layer gill net has a direct relationship with the mesh size and the individual size of the fished object, the reasonable utilization of fish resources, and the level of catch rate.
According to our analysis of the catches of two different meshes, the correlation between mesh size and body weight of the gill net is similar to the above formula.
3. The choice of material and thickness of the cable.
(1) Selection of network cable materials: The network cable is required to have high strength, thin and soft lines, and the network cable is transparent and colorless in water or has a color that is not easily found by fish. At present, most of the products used are nylon hemp yarns (polyester yarns) and nylon yarns (nylons), among which the rubber yarn materials are low in cost and light in operation.
(2) Selection of the thickness of the network cable: The thickness of the network cable of the snarling equipment has a great influence on the catch rate. Generally, the finer the cable, the less likely it is to be found by fish. The deeper the fish is embedded in the epidermis of the fish, the deeper the fish can escape, and the higher the catch rate. Conversely, the catch rate is low. Therefore, in the case of sufficient strength, the finer the cable selection, the better. There are two methods to determine the thickness of the gill net when it is designed. One of them is calculated according to the cable strength calculation method. The formula is: P=nQ/2k1k2. Where: n-safety factor, general gill net Take 1.5-2;
2 - indicates that a mesh consists of two network cables;
K1—indicates the ratio of the dry and wet no-nodule strength of the cable, and the kapok-like plastic yarn k1-0.8
K2—indicates the ratio of nodule to nodule breaking strength in the wet state of the cable, and KL=0.9
Q - The maximum amount of the catch of the catch in the mesh (approximately equal to the weight of the catch itself, ie Q = G), unit: kg;
P - the 1000-state breaking strength of the network cable, unit: kg;
4. The choice of upper and lower material and thickness:
The materials and thicknesses of the upper and lower classes are related to the slackness and softness of the mesh, but the selection should also be based on the reservoir's topography, landform, and mode of operation. In order to maintain sufficient slack and softness of the mesh, we chose a thinner 0.25/38 (diameter = 0.4 mm) polyethylene wire. The upper level adopts two 0.25/38 polyethylene wires, and its strength is enough; the lower one adopts a 0.25/38 polyethylene wire and a 0.25/33 polyethylene wire, which facilitates the fastening of the sinker and the bottom wire. After hooking, if it is a small object, it can be pulled up. If it is a large object, it can be broken to prevent the net clothing from being torn.
"Skirt net" is also a single-layer gill net type, due to the use of different upper and lower levels of horizontal shrinkage coefficient, so that the traditional rectangular gill net mesh becomes a fan-shaped upper short segment, when the fan-shaped mesh is floating Under the effect of sinkers and buoys, when standing upright in a certain water layer, it is in a “skirt†type “∽†shape wavy, so it is called “skirt netâ€. When the carp encounters the “skirt net†to turn around, it is arrested by wavy net clothes, thorns, wraps, bags, and collusion. In addition, the “fishing net†material selection and assembly process highlights: “two fine†The technical characteristics of (fine wire mesh, fine upper and lower wire), "two light" (light weight of squat, light buoyancy), "large" (large float spacing), and "small size" (small horizontal shrinkage coefficient) make the net In the water body, it has good relaxation and softness and enhances the entangling performance. At the same time, according to the characteristics of the squid transforming the life of the water layer, by adjusting the length of the buoy rope, the net gear is accurately distributed in the center fishery where the squid is active. Greatly improved the catch rate. This article describes the fishing nets and fishing methods of “Skirt Net†as follows:
One, nets
1. Netting materials, specifications, and dosage:
(1) Net clothing: 12cm large head adopts 0.25 rubber wire, 1400 heads long, 35 heads high, heading 14cm adopts 0.3 glue wire length 1200 meshes, and 30 heads high. The coefficient of horizontal shrinkage is 0.3 in the outline, 0.38 in the outline, and 0.955 in the vertical shrinkage coefficient.
(2) Upper class: 2 roots, 0.25/38 polyethylene wire, 52m piercing length, and 58m assembly line.
(3) The following outlines: 2 roots, 0.25/38 polyethylene thread length 66m, and 0.25/33 polyethylene thread length 70m.
(4) Floats: 51, 8cm2cm2cm foam blocks.
(5) Shen Zi: 161, 25cm4cm2cm
2. Net equipment assembly:
The two types of net equipment assembly methods are basically the same. Now, only the mesh size of 14cm is described.
(1) on the assembly method: first with a length of 52m of the upper class (called wear class), through the length of the net mesh head, and then with a length of 58m another upper class (called assembly) loaded float, Each of the two upper thread heads shall be kept at a length of 1m (as a net string for fixing or splicing nets when the net is placed). From 1m onwards, 1 float shall be placed per meter, 3 mesh nets shall be placed on the float, and 2 shall be placed between the floats. Head. In order to prevent the float from falling off due to excessive force when closing the net, when tying the float, wear the knot without hitting the knot, and only use the assembly to put double knots near the ends of the float.
(2) Under the assembly method: 0.25/38 polyethylene wire as the wear outline, 0.25/33 polyethylene as the assembly, 1 sink per 40cm, 2 heads in Shenzhong, and the net between Shenzi is 5.5 heads, Shen Zai beat a knot again. At both ends of the sinker, a shallow slot is clamped with a vise so that it can be fastened tightly. Loading method with floats.
3. Affiliated fishing tackle:
(1) Buoys: Bubble floats with a buoyancy of 400g. Each net (50m long) with 2-3. The buoy rope also uses a 0.25/38 polyethylene wire, the length of which depends on the deepest layer of the net, but generally does not exceed 20m.
(2) Shen Shi: Generally, each working ship is equipped with 2-4 pieces of heavy stone weighing 2.5kg-5kg. Shen Shisheng can use yellow-brown ropes with a diameter of 0.6cm-0.8cm or 0.25/320 polyethylene ropes. The length of ropes for each sinker is 30m-50m.
(3) Net boat: It is a 1t-bit, 3.2m-long small fascia board.
two. Fisheries law
1. "Try Network":
The method of “trial network†is that each fishing team lays the nets in water layers of different depths in different fishing grounds, and then conducts statistics, analysis, summary, and determination according to the catch rate and the site of the Internet for each group. The orientation of the center of the fishery in this season's squid activity.
2. Release:
In general, each net boat is equipped with 20-30 nets (1000m-1500m length). The nets are stacked horizontally in the midship of the net boat. Shen Zigang is located in the direction of the bow and the float is in the direction of the rear cabin. The net work is carried out by two people. The front cabin is a rowing boat and the Shenzhuang Gang. One person is responsible for the piling, float class and buoy hanging. When the net boat arrives at the fishery, the people in the rear cabin will throw the sinking stone into the water first. After the sinking stone is in the end, the upper net rope is tied to the sinking rope, and then the rowing boat is placed on the net. With the progress of the net boat, the net gear Water from the right side of the shipboard. When the last mesh was put, the upper mesh string was tied to the other sinking stone and the stone was thrown into the water. Then check if the buoy is loose or if the buoy rope is fully spread.
The network deployment time is usually before the daily sunset, and the special circumstances are flexible.
3. Net collection:
First, the boat was moved to the sinking buoy at the downwind position, and the Shen Shi was pulled up to close the net. When the two received their nets, one person received a floater class in the rear cabin and was responsible for arranging the buoys and controlling the ships. One person received the sinker class in the fore cabin, and the catches were taken from the near places. If there are three people collecting nets, one person can pick up the nets in the middle cabin and specialize in taking the catches. In the net collection, the nets, buoys and all kinds of ropes should be clearly arranged so as to facilitate the next net release.
three. Question Discussion
1. Determine the length and height of the net:
The length of the gill net is mainly determined by the width of the fishery water area and the convenience of operation. The length of the general unit mesh is 15m-50m, but there is no uniform standard everywhere.
The height of the gill net is determined based on factors such as the depth of the fishery, the habits of the fishing object, and the habitat layer. Within the depth of the fish habitat water layer, the higher the height of the net, the larger the catch area and the higher the catch rate. The net height of a typical single-layer gill net is 1m-5m.
2. Mesh size determination:
The thorn-based single-layer gill net has a direct relationship with the mesh size and the individual size of the fished object, the reasonable utilization of fish resources, and the level of catch rate.
According to our analysis of the catches of two different meshes, the correlation between mesh size and body weight of the gill net is similar to the above formula.
3. The choice of material and thickness of the cable.
(1) Selection of network cable materials: The network cable is required to have high strength, thin and soft lines, and the network cable is transparent and colorless in water or has a color that is not easily found by fish. At present, most of the products used are nylon hemp yarns (polyester yarns) and nylon yarns (nylons), among which the rubber yarn materials are low in cost and light in operation.
(2) Selection of the thickness of the network cable: The thickness of the network cable of the snarling equipment has a great influence on the catch rate. Generally, the finer the cable, the less likely it is to be found by fish. The deeper the fish is embedded in the epidermis of the fish, the deeper the fish can escape, and the higher the catch rate. Conversely, the catch rate is low. Therefore, in the case of sufficient strength, the finer the cable selection, the better. There are two methods to determine the thickness of the gill net when it is designed. One of them is calculated according to the cable strength calculation method. The formula is: P=nQ/2k1k2. Where: n-safety factor, general gill net Take 1.5-2;
2 - indicates that a mesh consists of two network cables;
K1—indicates the ratio of the dry and wet no-nodule strength of the cable, and the kapok-like plastic yarn k1-0.8
K2—indicates the ratio of nodule to nodule breaking strength in the wet state of the cable, and KL=0.9
Q - The maximum amount of the catch of the catch in the mesh (approximately equal to the weight of the catch itself, ie Q = G), unit: kg;
P - the 1000-state breaking strength of the network cable, unit: kg;
4. The choice of upper and lower material and thickness:
The materials and thicknesses of the upper and lower classes are related to the slackness and softness of the mesh, but the selection should also be based on the reservoir's topography, landform, and mode of operation. In order to maintain sufficient slack and softness of the mesh, we chose a thinner 0.25/38 (diameter = 0.4 mm) polyethylene wire. The upper level adopts two 0.25/38 polyethylene wires, and its strength is enough; the lower one adopts a 0.25/38 polyethylene wire and a 0.25/33 polyethylene wire, which facilitates the fastening of the sinker and the bottom wire. After hooking, if it is a small object, it can be pulled up. If it is a large object, it can be broken to prevent the net clothing from being torn.
Other Pharmaceutical Intermediates
Tetrabutylammonium Tribromide,Tetrabutyl Ammonium Tribromide,Trimethylamine Hydrochloride
Qidi Chemical Co., Ltd. , http://www.czchemicals.com