NZ739475B - Mesh screen maximizing production in mytilidae cultivation - Google Patents

Abstract

The present technology is a cultivation mesh screen (20) of minimum sieve that maximizes the aquaculture production and prevents tangling of the hangs, comprising: at least one cultivation hang (21) hanging from a mother longline (24) by means of holding means (22) and the mother longline (24) is joint to a controlled floatation means (4); attachment means (23), alternately jointing each cultivation hang (21) with an adjacent cultivation hang (21), thereby forming the cultivation mesh (20) with an area without sieve (25), wherein the cultivation mesh (20) is kept submerged under the water level (30) and the weight of the cultivation mesh (20) allows it to remain perpendicular with respect to the horizontal. int to a controlled floatation means (4); attachment means (23), alternately jointing each cultivation hang (21) with an adjacent cultivation hang (21), thereby forming the cultivation mesh (20) with an area without sieve (25), wherein the cultivation mesh (20) is kept submerged under the water level (30) and the weight of the cultivation mesh (20) allows it to remain perpendicular with respect to the horizontal.

Description

MESH SCREEN MAXIMIZING PRODUCTION IN MYTILIDAE CULTIVATION FIELD OF THE INVENTION The present invention relates to the aquaculture industry. In particular, this invention relates to a cultivation system that improves the environment for Mytilidae while they are in stages of growth and fattening, providing favorable environmental conditions for the growth and production yield per area of the used column of water. By means of a submersible float system, this technology minimizes the adverse environmental conditions such as freshwater areas in estuaries, exposure to the air due to waves, wave energy and, through a system of minimum filtering sieve, maximizes the use of the water column. These conditions allow the increase in productivity of cultivation compared to a traditional system of cultivation by hanging, where ropes are left to hang loose, subjected to water currents and severe weather, which generates low production, or even total loss of production when bad weather or storms occur.

The present invention comprises a mesh screen for a cultivation system to be used both in protected areas and non-protected areas (intense waves) without detachment of molluscs, thereby preventing production losses. The present screen configuration for the aquaculture cultivation system favors growth and production yield by area of water used. In addition, the present screen is incorporated into a submersible, controlled float system, which minimizes adverse environmental conditions when used in non-protected areas and by means of the screen system of minimum sieve the use of the water column is maximized. These conditions cause the cultivation productivity to increase, compared to the traditional system by hanging, and in particular, increases the yield of molluscs in exposed coastal areas, which are adverse for the molluscs cultivation.

For example, the Chilean mussel industry, located mainly in Los Lagos Region, has grown at an average annual rate of 30% in recent years. This has involved a greater demand for new coastal protected areas for the cultivation of about 2,400 hectares per year. However, the problems identified for cultivation in these areas at both national and global levels are: i) they present high densities of cultivation, overloading the ecosystems; ii) there is limited availability of new protected coastal areas; and iii) there is high competition for the use of these areas with other activities, such as salmon farming. For this reason, an opportunity for development of marine aquaculture on a large scale is foreseen, increasingly oriented toward sites of open sea and exposed coastal areas, which require appropriate technologies for the species to be cultivated.

STATE OF THE ART Currently, there are several technologies relating to aquaculture or fish farming.

Among them is the patent ES1043285 disclosing a technology for breeding or cultivation of mussels, specifically an improved nursery for growing mussels in open sea, wherein the nursery is formed from a rope or longline horizontally arranged, which is located in the mentioned position using floats located at the ends of the rope, consequently leaving the rope horizontally positioned, and fixed at a predetermined depth by means of chains pulled by one of its ends to the longline, whereas be the opposite end are pulled by mooring blocks or anchors located on the bottom of the sea, wherein the nursery has the following features: the rope or longline is made of polypropylene, and it is submerged by the action of floats positioned over the same, in adequate number to its length, the rope or longline remains submerged at high tide at about 4 meters from the surface, and at low tide at about 0.5 meters, wherein the rope or longline is connected with the floats to the bottom by mooring blocks or anchors or other similar elements, having an adequate weight to keep the ends anchored, and intermediate points of the longline using chains or similar elements, connected at one end to the rope and at the opposite end to the mooring blocks or anchors. From said rope hang a plurality of ropes located vertically, in which the seeds of mussels are placed for fattening inside the sea.

But the patent ES1043285 does not maximize the aquaculture production, because it does not efficiently use the cultivation area, since the plurality of ropes is placed vertically, without preventing the tangling of the hangs, which implies an inefficient use of the cultivation area. As shown in Figure 3 corresponding to the prior art, a plurality of cultivation hangs (21) hang from a mother longline (24). The longline (24) is supported by a rod (26) and uses floatation means to keep the cultivation hangs (21) from contacting the bottom of the sea. But, as seen in figure 3, sea currents or waves could strike the hangs, making them hit with each other. This implies a loss of production that in some cases could reach 90%. In addition, and given the length of the cultivation hangs (21), these get easily tangled with each other, hampering the handling of these cultivation hangs (21) and resulting in production losses.

SOLUTION TO THE TECHNICAL PROBLEM To remedy the technical problem, a change in the configuration of cultivation sleeves is presented, for maximizing the aquaculture production through a mesh screen that minimizes the sieve, allowing for a configuration which minimizes the area that cannot be used for the cultivation, or minimizes the sieve for water passage and maximizes the area for production of molluscs (Mytilidae), regardless of whether the mesh screen is located in protected areas or exposed areas for cultivation, where the exposed areas are adverse for the cultivation due to currents and/or high waves.

SUMMARIZED DESCRIPTION OF THE INVENTION The present invention provides a cultivation mesh screen of minimum sieve that maximizes the aquaculture production and prevents tangling of the hangs, the cultivation mesh screen comprising: at least one cultivation hang hanging from a mother longline by means of a holding means and the mother longline is joined to a controlled floatation means; attachment means, alternately joining each cultivation hang with an adjacent cultivation hang, thereby forming the cultivation mesh screen with an area without sieve, wherein the cultivation mesh screen is kept submerged under the water level and the weight of the cultivation mesh screen allows it to remain perpendicular with respect to the horizontal.

The design of the submersible cultivation mesh has features allowing the effect of waves to decrease (which causes line breaks and losses in the traditional systems), by placing the main float line holding the units of cultivation to a depth that may vary during operation. The difference in the submersible cultivation mesh with the traditional system is that the location of the floatation line is adjustable in the water column during the time of cultivation. The depth of the final design is defined according to the results obtained from measurement of the currents, the experience with the preliminary designs and the results of growth at different depths. This technological solution has the appropriate design for the cultivation of mussels in exposed coastal areas. Currently, this knowledge does not exist.

The technology of the cultivation system by traditional hangs, known as submersible longline, can be applied to molluscs cultivation (Mytilidae, Ostreidae and, Pectinidae) and macroalgae. These species require being suspended in the water column during their stages of growth. The screen is can be applied to Mytilidae.

The most relevant application is that, with this technology, it is possible to install cultivation centers in exposed coastal areas. In the case of Chile, there exposed coastal areas are not used due to the lack of technology for these purposes.

DESCRIPTION OF THE FIGURES Figure 1A shows a preferred embodiment of the cultivation mesh screen (20) formed by a single sleeve or cultivation hang (21).

Figure 1B shows another preferred embodiment of the cultivation mesh screen (20) formed by a plurality of sleeves or cultivation hangs (21).

Figure 2 shows a preferred embodiment of the cultivation mesh screen (20) formed by the sleeves or cultivation hangs (21) and auxiliary floatation means (2).

Figure 3 shows the traditional cultivation system by hangs of the prior art.

DESCRIPTION OF THE INVENTION As shown in Figures 1A and 1B, the present invention discloses a cultivation mesh screen (20) of minimum sieve that maximizes the aquaculture production and prevents tangling of the hangs, wherein the cultivation mesh comprises: at least one cultivation hang (21) hanging from a mother longline (24) by means of holding means (22) and the mother longline (24) is joint to a controlled floatation means (4); attachment means (23), alternately jointing each cultivation hang (21) with an adjacent cultivation hang (21), thereby forming the cultivation mesh (20) with an area without sieve (25), wherein the cultivation mesh (20) is kept submerged under the water level (30) and the weight of the cultivation mesh (20) allows it to remain perpendicular with respect to the horizontal or the sea bottom (31).

In a preferred embodiment, the distance between the cultivation hangs (21) is about 20 cm to 70 cm, and in another preferred embodiment, the distance between cultivation hangs (21) is about 30 cm to 50 cm.

In another preferred embodiment, the area without sieve (25) is about 400 cm to 4900 cm , and in another preferred embodiment, the open area without sieve (25) is about 900 cm to 2500 cm , where the area without sieve (25) formed by the cultivation hangs (21) and the attachment means (23) has a rhomboid shape.

In a preferred embodiment, the diameter of the cultivation hangs (21) is between 4 cm and 15 cm, and in a more preferred embodiment, between 5 cm and 10 cm.

The cultivation mesh (20) is kept in a determined position by weights (9), thereby holding the controlled floatation means (4) with tethers (7) to the bottom, using a clamp for the ropes or cables (6), and the location of the cultivation mesh (20) is known by means of marker buoys (3), held to the weights (9) with buoy cables (8), thereby forming a cultivation system (1), with the cultivation mesh (20) of the present technology.

In another preferred embodiment, and when the weight of the production in the cultivation mesh (20) exceeds the buoyancy of the means of controlled floatation means (4), this controlled floatation means (4) further includes some auxiliary floatation means (2) attached with ropes (5).

In addition, in another preferred embodiment, the cultivation mesh (20) is held to the sea bottom (31) by bottom tethers, not shown in the figures.

In another preferred embodiment, the cultivation mesh (20) is formed by a single cultivation hang (21) or is formed by a plurality of cultivation hangs (21).

In addition, the cultivation mesh (20) is kept submerged in a controlled manner by means of the controlled floatation means (4) under the water level (30).

The process comprises three stages: (1) Collection of the seeds of Mytilidae in its natural environment, wherein collectors are positioned in the mother longline for the larvae of Mytilidae to adhere to the same, and subsequently to be removed for the next stage; (2) Putting the seeds on a stringbed in the growth hangs. The seeds are separated from the collector manually. Once the seeds have selected, they enter a stringbed equipment. Ropes and seeds enter a pipeline of 100 to 120 cm. The seeds are put in a cylindrical screen of 5 mm having a knot at the beginning for allowing the accumulation of seeds and the rope inside of the same. In this manner, hangs for fattening are manufactured, with a total length of 400 m. (3) Meshing of the hangs. It consists of making a screen with the already manufactured hangs of about 2.5 m wide and about .6 m high. The total length of the hangs must be 80 m. These will be attached at one end to a rod of 3 m long and 80 mm in diameter, forming a sine of 8 m in depth. The hang is attached again to the rod, spaced 50 cm from the first attachment point. The process is repeated until completing the full length of the hangs. Then, the meshing of the screen starts manually, from one end of the hang, a first section of 50 cm is measured and a parallel separated section. These are joint together with a tie each 50 cm. This process is repeated until the bottom part of the sine formed by the hang, and further repeated with the rest of the hangs. The spacing between adjacent ties in the rod can fluctuate between 30 to 50 cm, and the initial depth of the sine formed with hangs can fluctuate between 5 to 10 m.

EXAMPLE OF APPLICATION The present technology and its components have been tested in an exposed coastal area, with flow speed between 2 cm/s and 12 cm/s, unlike protected coastal areas with flow speed of between 0.2 cm/sec and 1.2 cm/s, having excellent results for cultivation in these exposed areas. For example, seeds of Mytilidae were collected in its natural environment on a system of between 40 and 80 buoys of 350 liters jointed by a rope, called mother longline, which longline was arranged in the sea in areas known for the occurrence of Mytilidae larvae. In the mother longline, pieces of fishing nets made of polyamide material, discarded, with dimensions of 10 cm wide and long about 4 m were arranged. These pieces of nets are called collectors, to which the Mytilidae larvae is fixed.

After noting that the collectors have Mytilidae attached in a concentrated manner of between about 10 and 20 mm, the collectors are removed from the water, for putting the seeds in a stringbed for growth: each collector is located in a working platform, in which the seeds are shed from the collector. If standardization of the seed size is desired, the seeds are arranged in a sorting machine, which consists of a funnel where the seeds enter, then falling into a tube with screw conveyor, taking them to a first section with slots that select a desired size, being able to obtain up to three sizes of seeds. In this manner, it is possible to obtain seeds of different sizes. Then, the seeds are moved to a stringbed machine, consisting of a funnel through which the seeds enter with high-pressure water toward a transversal tube with a diameter of about 7 mm. A rope of 18 to 22 mm goes through the transversal tube. The end of the rope is pulled to move it forward, moving the seeds and the rope through the pipe of about 100 to 120 cm. At the end of this metallic tube, at its edge, it overlaps with a cylindrical cotton mesh with a sieve of 5 mm, allowing the seeds to be deposited in this mesh, having at its starting end a knot, thereby allowing the accumulation of seeds and rope inside the cotton sleeve, wherein said rope comprises filaments where the seeds are held. With this system, fattening hangs are manufactured, which will be placed in the cultivation system for its growth in the sea.

These hangs have a total length of up to 400 m depending on the length of desired the rope to be included in the mother longline with seeds. Then the meshing of the hangs of the present invention is performed, to maximize the area of the water column, wherein the cultivation mesh (20) is formed by the meshing of the cultivation hangs (21), having about 2.5 m wide and about 5.6 m high, with a total length of the hang of about 80 m. In a rod of 3 m in length and a diameter of 80 mm, one end of the hang it tied to the rod, forming a sine of 8 m in depth, tying again the hang in the rod, separated by 50 cm from the initial tie. This process is repeated until completing the full length of the hang. Then, the meshing is performed, from one end of the hang with a spacing of 50 cm between hangs, and at the same time, these hangs are joined with the attachment means (23) every 50 cm, to form the cultivation mesh (20).

With the present cultivation technology, production increases in 1.9 times per line compared to the traditional cultivation system by hangs, known as longline system. This can decrease maintenance costs by 20%, avoiding tangling of the hangs and enabling to perform the entire process of fattening in four months. A graphical way to see the efficient use of the production area is to compare Figure 1A, 1B or 2 with figure 3. By observing these figures, it is possible to see that figures 1A, 1B and 2 have double the length for cultivation hangs (21) with respect to Figure 3 (prior art), with the same aquatic area for production. In addition, the present cultivation mesh (20) is useful for cultivation in both protected areas and non-protected areas.

List of constituent elements: Cultivation system (1) Auxiliary floatation means (2) Marker buoys (3) Controlled floatation means (4) Ropes (5) Clamp for ropes or cables (6) Bottom tethers (7) Buoy cables (8) Weights (9) Cultivation mesh (20) Cultivation hangs (21) Holding means (22) Attachment means (23) Mother longline (24) Area without sieve (25) Rod (26) Water level (30) Bottom (31)

Claims (13)

CLAIMS :

1- A cultivation mesh screen of minimum sieve that maximizes the aquaculture production and prevents tangling of the hangs, the cultivation mesh screen comprising: at least one cultivation hang hanging from a mother longline by means of a holding means and the mother longline is joined to a controlled floatation means; attachment means, alternately joining each cultivation hang with an adjacent cultivation hang, thereby forming the cultivation mesh screen with an area without sieve, wherein the cultivation mesh screen is kept submerged under the water level and the weight of the cultivation mesh screen allows it to remain perpendicular with respect to the horizontal.

2- The cultivation mesh screen according to claim 1, characterized in that the distance between the cultivation hangs is about 20 cm to 70 cm.

3- The cultivation mesh screen according to claim 1, characterized in that the distance between the cultivation hangs is about 30 cm to 50 cm.

4- The cultivation mesh screen according to claim 1, characterized in that the area without sieve formed by the cultivation hangs and the attachment means has a rhomboid shape.

5- The cultivation mesh screen according to claim 1, characterized in that the area without sieve is about 400 cm to 4900 cm .

6- The cultivation mesh screen according to claim 1, characterized in that the area without sieve is about 900 cm to 2500 cm .

7- The cultivation mesh screen according to claim 1, characterized in that the diameter of the cultivation hangs is between 4 cm to 15 cm.

8- The cultivation mesh screen according to claim 1, characterized in that the diameter of the cultivation hangs is between 5 cm to 10 cm.

9- The cultivation mesh screen according to claim 1, characterized in that the controlled floatation means, further comprises auxiliary floatation means joined by means of ropes.

10- The cultivation mesh screen according to claim 1, characterized in that the cultivation mesh screen is held to the sea bottom by bottom tethers.

11- The cultivation mesh screen according to claim 1, characterized in that the cultivation mesh screen is formed by a plurality of cultivation hangs.

12- The cultivation mesh screen according to claim 1, characterized in that the cultivation mesh screen is kept submerged in a controlled manner by means of the controlled floatation means under the water level.

13- A cultivation mesh screen, substantially as herein described with reference to