Method to define selectivity of trawl net. RU patent 2483535.

IPC classes for russian patent Method to define selectivity of trawl net. RU patent 2483535. (RU 2483535):

Another patents in same IPC classes:

Method of determining trawl catching efficiency / 2440589
Method involves finding the quotient from dividing the number of fish caught by the trawl by the number of fish in front of the trawl, determined using an echo sounder on a trawl board. An additional hydroacoustic echo sounding device is mounted the trawl warps opposite each other outside the zone of effect of the trawl boards on the fish. The additional hydrocoustic echo sounding device facilitates hydroacoustic location of fishing objects in front of the trawl. Hydroacoustic location from the trawl board enables to determine the position of the boundaries of zones within which the number of fish in front of the trawl is estimated.

Method and device for trawl fishing / 2377773
Proposed method envisages usage of a net with the help whereof the catch is captured and collected during trawl fishing. The end of the trawl net is designed to be open. At the end of the trawl net a fish pump is installed with its suction side turned towards the trawl net and its pressure side connected to a fish duct hose. In the course of trawl fishing the catch is directed towards the trawl net and gradually pumped into the fish duct hose for delivery onboard a fishing trawler. With the help of a supply hose the fish pump is connected to an electric power supply device providing for the pump actuation. Before the fish pump on the suction side a devise is positioned providing for removal of nuisance bycatch and foreign bodies from the flow transported. The device includes a trawl net for the catch at the end whereof fish duct hose is attached for delivery onboard a fishing trawler. The trawl net end is designed as an open tunnel composed of trawl nets. The tunnel has an inlet turned towards the trawl net and an outlet leading outside the trawl net. In the centre of the tunnel composed of trawl nets a fish pump is installed ith its suction side turned towards the trawl net. The fish pump pressure side is connected to a fish duct hose. The fish pump is installed at a distance from the walls of the tunnel composed of trawl nets. On board the fishing trawler an electric power supply device is installed connected to the fishing trawler via a supply hose.

Sorting grate for trawl and its production method / 2354115
Sorting grate consists of reinforced frame, longitudinal and transverse braces from polymeric material. The gate consists of sections rigidly joined between each other along the internal boundary. Each section is composed of casting construction differed by the shape of the outer boundary made of polymeric material on the basis of synthetic gum. Longitudinal and transverse braces of the outer boundary of the sections are designed in the form of hemispheric section at their junction point. Method of sorting gate production envisages production of all gate elements: frame, longitudinal and transverse braces made of reinforced polymeric material. The gate is assembled from single casting section joining them rigidly through binding along the outer boundaries designed in the form of hemispheric section. Casting moulds with hollows corresponded configuration and size of section elements are prepared for moulding of the sections. The reinforced material is panned in the hollows and filled them under pressure with polymeric material based on synthetic gum.

Method for determination of trawl catch efficiency / 2346432
Method implies use of hydroacoustic echo-ranging device to determine amount of fish in front of trawl. Hydroacoustic echo-ranging device may be installed at one and/or both trawl boards. Echo ranging of target stocks in the space between trawl boards and trawl wings is carried out either from one board towards the other board or from both boards alternately towards one another. Sound impulses are emitted simultaneously or alternately. Then number of caught fish is divided by total number of fish in front of trawl to determine catch efficiency.

Device preventing fish from leaving trawl / 2343704
Device used for preventing fish from leaving the trawl consists of equal groups of acoustic-and-optic emitters of sound and light pulse signals, and echo-sounding fish control sensors in the trawl cross sections, which are discretely located along the trawl envelope from its mouth to the trawl bag. Echo-sounding sensors are installed after the appropriate acoustic-pulse emitters relative to trawl mouth, and acoustic-optic emitters are made so that they can form acoustic and optic areas directed at an angle to longitudinal trawl axis in the direction of trawl bag.

Trawl construction / 2298319
Proposed trawl includes sea product or biomass catching member and conveyer for transferring sea products or biomass to another ship. Conveyer is provided with hose which has upper section at ascending inclination in way of sea surface. Trawl is provided with injector mounted in upper section of conveyer at the same ascending inclination. Injector provides for control of passage of sea products or biomass from trawl through hose due to ascending inclination. Trawl is provided with extended rigid or flexible collecting cage which consists of several rigid collecting cages and several flexible collecting cages. Extended collecting cage has first part including inlet opening which is located behind trawl and is connected to it. Collecting cage has second part to which inlet opening leads. Second part has opening through which water may be filtered. Collecting cage has third part located after second part. Third part is connected with bell mouth. Filtering screen is mounted before this bell mouth. Transferring hose is connected with bell mouth and is used for transferring the sea products or biomass to receiving ship. Hose supplying the fluid medium is used for injection of this medium. Hose may be used for transferring the sea products or biomass from collecting cage to ship. Fluid medium supply hose is provided with injector and transferring hose is made at ascending inclination towards sea surface and towards rear wall of cage which is distant relative to it. Trawl is provided with extended collecting cage which is connected with rear terminal area of trawl; it passes to the second part provided with openings for screening the water and terminates in part located below in way of flow. Sea products or biomass transferring hose or pipe opens to lower or rear part of cage through bell mouth. Provision is made for filtering screen for filtering-off the sea products or biomass which are not to be supplied to bell mouth. Air or another fluid medium is fed from ship via supply hose for injection into transferring hose or pipe to obtain injection effect or method of shift of fluid medium for transfer of sea products or biomass from collecting cage to ship. Air or another fluid medium is fed from ship via air supply hose for injection at point on transferring hose or pipe by means of injector found in upper part of transferring hose or pipe at ascending inclination towards sea surface.

Method for determining of trawl net catching coefficient / 2275021
Method involves finding partial of dividing the number of fishes caught by means of trawl net by the number of fishes downstream of trawl net, the latter number being defined by means of echo sounder, which is disposed above floating means moved synchronously above trawl net mouth space. During movement of echo sounder, cone of hydroacoustic beam overlaps space between otter trawl boards and trawl net wings.

Rope pelagric trawl / 2249948
Proposed rope pelagric trawl consists of front rope and end eight sheet net parts and float, fishing and side lines. Hydrodynamic panels are installed on float line, and fishing line is furnished with chain. Difference in lengths of float and side lines and fishing and side lines is 7 m.

Method to define selectivity of trawl net / 2483535
Invention relates to commercial fishery. The method is realised by comparison of catch and readings of a hydroacoustic sonar. The hydroacoustic sonar comprises several blocks arranged on upper and lower framing ropes of the net oppositely to each other at the equal distance. The distance between blocks is calculated according to a certain dependence, based on the angular width of existing characteristics of directivity of a probing beam of a block and a value of vertical opening of the trawl net.

FIELD: agriculture.

SUBSTANCE: invention relates to commercial fishery. The method is realised by comparison of catch and readings of a hydroacoustic sonar. The hydroacoustic sonar comprises several blocks arranged on upper and lower framing ropes of the net oppositely to each other at the equal distance. The distance between blocks is calculated according to a certain dependence, based on the angular width of existing characteristics of directivity of a probing beam of a block and a value of vertical opening of the trawl net.

EFFECT: invention makes it possible to validly and in a quality manner determine selectivity of a trawl net directly in process of trawling.

1 dwg

The invention relates to the fishing industry, in particular to commercial fisheries, to methods of determining the selectivity of trawl.

There are ways to determine the selectivity of fishing trawls. In the way that uses alternating trawling ( A.I., 1974. The scientific basis of selective fishing. M. Food industry-th .180-182; ICES Cooperative Report N215, 1996, Manual of methods of measuring the selectivity of towed fishing gears. Paloegade 2-4DK-1261 Copenhagen K. Denmark, c.6-7), performed with the same vessel in the same area, in turn operate trawls with different sizes of meshes. Received by each trawl catches analyze and by matching the size and quantitative compositions of catches evaluate selective (election) properties compared trawls. The disadvantage of this method is a practical impossibility to assess the actual selectivity specific audited or investigated trawl, and only the definition of the differences in the selectivity of this and conditionally control of the trawl.

These drawbacks, as well as the complexity of the implementation is characterized by the method of determining the selectivity of trawl parallel, concurrent trawls, when trawling are produced strictly with two similar vessels, armed same trawls ( A.I., 1974. The scientific basis of selective fishing. M. Food industry-th .183-184; ICES Cooperative Report N215, 1996, Manual of methods of measuring the selectivity of towed fishing gears. Paloegade 2-4DK-1261 Copenhagen K. Denmark, c.7). The parish in the area of hauling from both vessels simultaneously give trawls, on parallel courses with a minimum distance between the courts on a command from one of the vessels. Raise trawls on Board simultaneously, the catches are approximated by the size and quantitative composition.

Also known way to determine the selectivity of fishing trawls, based on application of net coatings (ICES Cooperative Report N215, 1996, Manual of methods of measuring the selectivity of towed fishing gears. Paloegade 2-4DK-1261 Copenhagen K. Denmark, c.6). Trawl or part of the cover network of large sizes so that the fish pass through the core network, delayed covering network. After trawling separately pour out and take account of the catch from the bag trawl and covering the network. Selectivity of the trawl is determined on the basis of the ratio (n trawls) size-the quantitative composition of fish, known in the trawl, equal size-quantitative composition of the fish caught in the bag trawl plus size-quantitative composition of fish network covering, and the composition of remaining in the trawl bag, i.e. (specified) composition of the catch. This method allows to get several more reliable results on the selectivity of the investigated trawl, but is significantly more complex in practice. In addition, in connection with additional external coating modified and characteristics of the trawl, which would adversely affect the representativeness of the results of determination of its selectivity.

Closest to the proposed a method for determining the selectivity of trawl fishing with the use of acoustic devices (assessment of bulk acoustic density, S A ) (Somerton D.A., K. Williams, von Szalay P. G. and the Rose .S. 2011. Using acoustics to estimate the fish-length selectivity of trawl mesh. ICES Journal of Marine Science, 68:1558-1565). Size-the quantitative composition of the fish, included in the mouth of the trawl (trawl), which is defined by the use of two estimates inverse acoustic scattering measurements installed aboard ( hull) equipment vertical action actual acoustic backscatter concentrations of fish below the boat through within a layer of water captured trawl (thickness height equal vertical disclosure trawl), and theoretical assessment acoustic backscatter, which would have turned out (would be) from fish caught with regard to its abundance, size distribution (length) and acoustic target strength TS fish, i.e. the ratio of TS from L - length of the fish (which are available for a number of commercial fish species). Accordingly, the selectivity of the audited trawl is estimated (determined) proceeding from the achieved a specified way the ratio of the size-quantitative composition of fish, known in the trawl, and the size and quantitative composition of fish in the received catch. In this work (Somerton D.. and others, 2011) States that in case of comparative tests of the proposed method with the method coatings trawl the results of determining the selectivity were similar.

He is free from the drawbacks of the above known methods has no effect on the characteristics of the trawl, however selectivity estimate its use have insufficient accuracy and reliability in relation to the practical impossibility of security integration reflected from fish signals only within the territory of the mouth of the trawl, caused by the expansion of the front radiated acoustic oscillations any hydroacoustic equipment, and certain assumptions made during the translation of the testimony of bulk acoustic density S A size-quantitative the composition of fish, a member of the trawl. In addition, in many situations it is unlikely that the size and quantitative composition-feeding fish, which is recorded in the layer of water beneath the boat, is the same (stay the same) at the approach to it the mouth of the trawl due to the influence of noise trawler, visual fish reactions on trawl , cables, trawl and due to the impact of other factors on fish behavior. This will also negatively affect the accuracy of selectivity estimation.

The technical result in the implementation of the declared method is to obtain reliable and qualitative determination of selectivity fishing trawl directly at real trawls, by providing opportunities for a more accurate assessment of the size-quantitative composition of fish, included in the trawl.

The task is achieved in the method of determining the selectivity of fishing trawl by comparison of parameters of the sonar device and received the catch of the trawl, ultrasound device consists of n-th number of blocks and are placed on the upper and lower rebounds trawl on equal segments opposite each other, with the length L is determined proceeding from the angular width active directional characteristics α the probing beam block by the formula L=2htgα/2, where h is the vertical disclosure of the trawl, a - the angle of the probe beam, fish at the mouth of the trawl is carried out by cross-signal.

Figure 1 shows a side view, during their time at sea.

The method is shown trawl 1, the top 2 and lower 3 rebounds, ultrasound device 4, consisting of n-th number of blocks (4 1 ,4 2 4 ...n/2 , 4 n/2+1 ,4 n/2+2 ,4...n ), and trawler 5.

Two equal groups of blocks of the sonar device 4 apartment at equal distances on the top 2 bottom and 3 rebounds trawl 1. All blocks have identification numbers, 4 1 , 4 2 4 ...n/2 for the headline and 4 n/2+1 , 4 n/2+2 4 ...n for the bottom. Each block group top headline is located next to the appropriate block bottom rebounds (by numbers, i.e. 4 1 opposite the 4 n/2+1 , 4 2 opposite the 4 n/2+2 ...4 n/2 opposite 4n) to provide an acoustic overlap specified pairs of blocks appropriate surveillance zone in connection with certain taper their characteristics orientation. When driving trawl 5 space of his mouth overlaps sonar beams from each of the groups echolocation blocks towards each other.

Work on the proposed method is as follows. After the arrival of the ship in the area of operation before starting the scan selectivity of trawl one group echolocation 4 blocks mounted on the top 2, the other on the bottom 3 selection of the trawl, 4 blocks in each group an equal number. Blocks 4 placed at equal intervals in front of each other, while the length L is determined proceeding from the angular width of the existing directional characteristics α the probing beam block by the formula L=2htgα/2, where h is the vertical disclosure of the trawl, a - the angle of the probe beam, fish at the mouth of the trawl is carried out by cross-signal.

Echolocation blocks of 4 top 2 picks are connected to each other using the cables of communication (Fig. not shown), and this group is connected to the cable communication line with the vessel. After impact of trawl 1 all 4 blocks will stay in standby mode, i.e. on their electronic circuits will be fed with power supply from own batteries with their own pressure sensors. Then, upon running the code signal from the ship begins to work the extreme number 4 : 1 leading the echolocation unit of the top 2 picks installed on one of its edge. He radiates a probe pulse in the direction of the corresponding box 4 n/2+1 lower 3 rebounds, accepts and stores (stores) reflected from fish signals. At the parish of the probe pulse to the unit 4 n/2+1 group's bottom 3 rebounds, it is highlighted this unit and it will start radiation towards the top 2 picks up the probe pulse unit 4 n/2+1 group's bottom 3 rebounds. This block begins to accept and remember echoes from fish from the area of the mouth of the trawl 1. When taking the probe pulse unit 4 n/2+1 group's bottom 3 rebounds unit 4 1 group top 2 picks closes the receive path of this unit and with a beep code on unit of the top 2 picks set in the middle part. Separation distance runs echolocation blocks 4 provides for the exclusion of any acoustic influence on each other. When taking the probe pulse unit 4 n/2+1 group lower headline reflected from the top 2 foot-rope, closes the receive path block 4 n/2+1 group's bottom 3 rebounds. By means of a code signal from the 4 group 1 top 2 picks adopted by the unit group of the top 2 picks set in the middle part of the top 2 picks specified unit emits a probe pulse in the direction of the respective unit of the group of the bottom 3 rebounds. These units are similar blocks 1 and 4 4 n/2+1 .... When taking the probe pulse of the median unit of the group of the bottom 3 rebounds median unit of the group of the top 2 picks closes the receive path of this unit and with a beep code on unit 4 2 groups headline that works similarly, block 4 1 . Next block 4 group 2 top 2 picks served the beep code on the unit start-up group of the top 2 picks installed side by side with median unit of this group, in the direction of her last extreme block 4 n/2 etc. After the start and end of one cycle of the work of the last (second deadline) block 4 n/2 the group of the top 2 picks up with a beep code (similar to the transmitted from the vessel) at the re-launch of unit 4 1 group top 2 picks up and starts a new (second) the period of employment echolocation blocks the top 2 bottom and 3 rebounds. The result is a consistent scoring of the entire zone, the mouth of the trawl 1, reception and storage of echoes from fish from this area. In connection with the high speed of propagation of acoustic vibrations in the water environment and the relatively small distances between the top 2 and bottom 3 selection of objects / things, at the vertical disclosure trawl 50 m, the number of echolocation blocks in the group, equal to 10, and a sankhobe 23 degrees, the whole area of the mouth of the trawl 1 will be covered for the time equal to about 2/3 with (namely, at the speed of sound 1500 m/s and the total distance passable sound at 10 blocks, and a distance of passage for one unit equal to 50 x 2=100 m, the total time will be equal to 1000/1500, i.e., 2/3). Taken echoes are remembered and stored in each block. Immediately after the beginning of the sample (lift) of trawl vessel signal on off echolocation blocks.

After the lifting of the trawl 1 aboard the trawler count size-quantitative composition of the caught fish trawl. Blocks 4 hydroacoustic equipment removed and stored them in the acoustic information - wiggle - read for further processing. The result will be presented electronic echogram echolocation blocks 4, received during trawling. With the help of known computer programs used in marine scientific research equipment and applied under normal hydroacoustic shooting, for example in the EC-60 company , and others, determine the values of bulk acoustic density, S A , histogram grain size distribution and, consequently, the size and quantitative composition of fish, held in trawl 1. If necessary, conducted clarifications received . Based on the ratio of the size-quantitative composition of fish, included in the trawl, and the size and quantitative composition of fish in the resulting yield is determined by the selectivity of the audited the trawl.

As a result, the definition of bulk acoustic density S A fish directly at the mouth of the trawl and immediate (direct) acoustic assessment of the size composition of fish passing in trawl (at the mouth of the trawl), is provided to increase accuracy and reliability of the identification of selectivity of trawl.