FR3076183A1 - AUTOMOTIVE STRUCTURE OF CONCHYLICULTURE - Google Patents

Abstract

A self-floating shellfish farming structure comprises a pillar (2), substantially cylindrical, and at one end of the pillar, a fastener adapted to be attached to an aquatic bottom. The pillar (2) has an internal cavity and is provided with at least two valves each disposed in the vicinity of a respective end of the pillar and allowing access from the outside of the pillar to the cavity to fill and empty it at less partially of a fluid of lower density than that of water.

Description

The invention relates to a self-floating structure, applicable in particular to shellfish farming and more particularly to mussel farming.

Faced with the population explosion and the exponential increase in protein consumption, the World Bank’s Fish To 2030 prospective study estimates that the marine kingdom must supply and meet 65% of the needs of the world’s population. This represents the minimum growth required of 5-10% per year for this sector by then. Basing this growth on fishing would lead to overexploitation of the oceans and fish populations.

Aquaculture therefore has a particularly important role to play in this scenario. Thus, according to the most optimistic projections on the contributions of world fishing, 2/3 of the needs in aquatic products will have to be met by sustainable, ecologically intensive aquaculture with a positive social and environmental impact. In 2013, aquaculture provided 48% of seafood products for human consumption. This contribution was 12% just 20 years ago.

Men have been consuming shellfish since time immemorial. With nearly 2 million tonnes produced annually, mussel farming differs from other forms of aquaculture in that the growth of individuals in breeding is ensured by the natural production of phytoplankton in production areas. No additional feed is therefore necessary in this form of aquaculture. Its success is mainly based on maintaining a quality of water compatible with the growth of phytoplankton and product safety.

The farming time of less than two years, the low costs of supplying juvenile shellfish and the absence of additional food, energy or fresh water consumption during the farming phases allow mussel farming. to be a sustainable source of protein. The low environmental impact and the high food quality of mussel production make it a good response to the needs mentioned. Increasing the production capacity of this sector can only be achieved through innovations in site access, production techniques, protection against predation and management of business waste. The sustainability of mussel culture will be linked to the maintenance of the quality of the environments and their primary productivity, as well as to the enhancement of products by processing.

The breeding sites, exclusively marine, are located in lagoons or in coastal areas which are influenced by telluric organic and mineral contributions favoring the primary productivity of phytoplankton. These production areas may be subject to pollution of direct human origin or through the contribution of watersheds and conflicts of use with professional fishing and recreational boating. The strength and recurrence of climatic bad weather and the pressure of predation also constrain the adaptation of breeding technologies to the point of calling into question, in certain areas, the economic viability of this activity.

Juveniles come from natural reproduction and their recruitment is carried out either by fishing for juveniles on natural supports (for example rocks) or by harvesting on artificial catchment supports, or directly on other mussels in breeding .

The farming techniques are mainly differentiated by the nature of the structure (fixed, floating or submerged) and that of the supports (flexible, rigid or containers) which allow animals to be kept in the water column. The bathymetry and the climatic conditions of the different production zones guide the typology of possible breeding structures; the possibilities of access to forms of mechanization and the cost of labor guide in part the nature of the breeding supports used.

These techniques face many challenges.

Traditional shellfish farming structures use stakes or "bouchots" planted in the seabed, grouped in rows of stakes. These piles can be considered as pillars, substantially cylindrical, devoid of specific attachment means to the seabed.

Other traditional structures use float systems, for example as described in patent application EP 0 860 111 A1. Other systems are also known by the term "die". A chain generally designates a suspension farming device consisting of a hawser, maintained on the subsurface by floats and at the bottom by anchors, and to which rearing ropes are attached

All of these structures are problematic, particularly for their resistance to weathering and for the maintenance and adjustment of the buoyancy of the assembly during the growth of the shellfish product.

In fact, when a sector drops out, it acts like a saw on the neighboring sectors, without counting the decrease in the speed of growth of the animals and the decrease in the filling rates after the storms.

The working conditions of the longline fishing are also very trying, the handling by crane of the hawsers presenting a significant risk for the safety of the sailors. As a result, it is not possible to work in strong or agitated conditions, which further reduces productivity.

The present invention improves the situation. Thus, the invention provides a self-floating shellfish farming structure, comprising a pillar, substantially cylindrical, characterized in that the structure comprises at one of the ends of the pillar a clip suitable for being fixed to an aquatic bottom, and in that the pillar has an internal cavity and is provided with at least two valves each arranged in the vicinity of a respective end of the pillar and allowing access from the outside of the pillar to the cavity to fill and empty it at least partially of a fluid with a density lower than that of water.

In various variants, the structure according to the invention may have one or more of the following characteristics:

the pillar comprises a cylindrical tube closed by a plug at each of its ends,

the pillar comprises several elementary cylindrical tubes interconnected by sleeves,

- the attachment suitable for being fixed to an aquatic bottom comprises two chains each fixed to the bottom by a respective screw anchor,

the structure comprises a mooring collar fixed by clamping around the side wall of the pillar, this mooring collar having two points of attachment of said chains connecting the pillar to the aquatic bottom,

- the pillar cavity is occupied by air.

- the internal cavity of the pillar occupies a major part of the volume of the pillar,

- at least one float is associated with the clip, and

- The structure includes a device for protection against predation by net covering the entire structure.

The invention also relates to a method of operating a self-floating shellfish farming structure, comprising the following operations:

a) Provide a substantially cylindrical pillar and comprising at one end of the pillar a clip suitable for being fixed to an aquatic bottom, an internal cavity, and two valves each arranged in the vicinity of a respective end of the pillar, making it possible to access the cavity from the outside of the pillar to fill and empty it,

b) Lower the pillar into the water and attach it to the seabed,

c) Fill the pillar with a fluid density lower than that of water.

In various variants, the structure according to the invention may have one or more of the following characteristics:

- operation b) is carried out by means of two chains each fixed to the bottom by a respective screw anchor,

- operation b) is carried out by tightening a mooring collar around the pillar and attaching the chains to the mooring collar,

- operation c) is carried out with air as a fluid with a density lower than that of water,

- operation c) includes:

cl) The opening of the valves;

c2) Injection of the fluid through the valve closest to the surface of the water;

c3) The closure of the valves when a desired buoyancy is obtained, and

- the method further comprises the following operation:

d) using the valves, fill the pillar with water so that the structure sinks to the bottom of the aquatic environment.

Other characteristics and advantages of the invention will appear more clearly on reading the description which follows, taken from examples given by way of illustration and not limitation, drawn from the drawings in which:

- Figure 1 shows a side view of a structure according to the invention implemented in a marine environment;

- Figure 2 shows a side view of the pillar of Figure 1;

- Figure 3 shows side views of detail III of the lower end of the pillar of Figure 2;

- Figure 4 shows side views of detail IV of the upper end of the pillar of Figure 2;

- Figure 5 shows a sectional view of the mooring collar of Figure 2,

FIG. 6 represents a profile view of the mooring collar of FIG. 3, and

FIG. 7 represents an alternative embodiment of the pillar of FIG. 2.

The drawings and the description below essentially contain elements of a certain nature. They can therefore not only serve to better understand the present invention, but also contribute to its definition, if necessary.

Figure 1 shows a side view of a structure 1 according to the invention implemented in a marine environment.

The structure 1 comprises several pillars 2. Each pillar 2 has two ends 3 and 5, called the low and high ends respectively. The lower end 3 has fasteners comprising two chains 7 fixed to the bottom by two anchors 9 for each pillar 2.

The fastener further comprises a shackle 11 fixed to each end of each chain 7 making it possible to fix it to its pillar 2 and to its anchor 9. The anchors 9 are arranged regularly, typically every 2.5m to 5m for a depth 15 to 20m deep. As a variant, the anchors 9 can be replaced by rails fixed to the seabed or by concrete moorings, the chains 7 being attached with a spacing similar to that of the anchors 9.

The structure 1 also includes immersed floats 13 and emerged floats 15. The floats 13 and 15 are installed for tracking purposes. They are typically divided into two groups. A first group comprises two emerged floats 15 fixed to the most extreme anchors 9 of the structure 1. A second group comprises a float 13 fixed to each anchor 9, and all the floats are immersed about 5m from the seabed.

Alternatively, the floats 13 and 15 could be omitted or distributed differently. Still, as a variant, the floats 13, which are used mainly for locating the anchorages, can be removed after the structure 1 has been put in place.

FIG. 2 represents a side view of the pillar 2 of FIG. 1.

The pillar 2 comprises elementary cylindrical tubes of high density polyethylene (HDPE) 103 interconnected by sleeves 105. The pillar is closed by a plug 101 at its ends 3 and 5. In the example described here, the assembly of the sleeves 105 and plugs 101 is produced by welding or electro-welding.

As a variant, the elementary cylindrical tubes 103 can be composed of other synthetic materials or of non-synthetic materials. Optionally, the elementary cylindrical tubes 103 interconnected by sleeves 105 can be replaced by a single cylindrical tube or connected together without sleeves.

The pillar 2 also includes, near each of its ends 3 and 5, a mooring collar 117. As a variant, there is only one mooring collar 117, near the lower end 3.

FIG. 3 shows side views of detail III of the end 3 of the pillar 2 of FIG. 2.

The pillar 2 has a valve 107 at the end 3. The pillar also has at its end 3 a plug 101. The valve 107 is connected to the pillar by a right angle bend 111 and a bypass saddle 113. The pillar 2 has an internal cavity 115. Next to the end 3 is fixed a mooring collar 117 around the pillar 2.

The plug 101 and the bypass saddle 113 seal the internal cavity 115 of the pillar 2. The mooring collar 117 is assembled to the pillar 2 by tightening. The valve 107 is connected to the internal cavity 115, which makes it possible to access it from outside the pillar 2 and to fill and empty it with water or air.

In another embodiment, the valve 107 is directly connected to its bypass saddle 113 without a right angle bend 111. As a variant, the air is replaced by another fluid with a density lower than that of water. Still alternatively, only the valve 107 could be present, the valve 109 being omitted. Finally, the valve 107 and / or the valve 109 could be a solenoid valve. In the case of valve 109, this would avoid the intervention of a deep diver under certain conditions.

Figure 4 is identical to Figure 3, except that it relates to the end 5 of the pillar 2.

Here, the valve 107 is thus replaced by a valve 109 which is arranged similarly to the valve 107 and has the same functions and interactions with the internal cavity 115 and the same variants.

FIG. 5 represents a sectional view of the pillar 2, illustrating the arrangement of the mooring collar 117 in FIG. 2.

The mooring collar 117 has two symmetrical half-collars 119. Each mooring collar 119 has two holes 121 and two holes 123 symmetrically arranged at its ends.

The mooring collar 117 is arranged around the pillar 2, and fixed to the latter by tightening. The clamping attachment ensures the attachment between the pillar 2 and the chain 7 by the shackle 11 without compromising the tightness of the internal cavity 115 (as opposed to fixing by screwing in the body of the pillar 2). The hole 121 is arranged to receive a screw and a nut in order to tighten the mooring collar 117 around the pillar 2. The hole 123 allows the shackle 11 to be hooked to connect a chain 7 to the pillar 2. Optionally, the mooring collar 117 can also be fixed by gluing or any other means guaranteeing the tightness of the internal cavity 115.

FIG. 6 represents a profile view of the mooring half-collar 119 of FIG. 5. The mooring half-collar 119 comprises two holes 121 and two holes 123.

In shellfish farming and in particular in mussel farming, the structure 1 is composed of several pillars 2 arranged regularly in a seabed.

Its installation is carried out according to the following operations: an anchor fixing operation 9, a shore preparation operation, a launching operation and a buoyancy adjustment operation.

The fixing of the anchors 9 begins with the preparation on the ground of a regular tracking means in order to regularly place the anchors 9, typically a rope with regularly spaced markings. The two extreme anchors 9 are then fixed to the seabed. The rope is stretched between the extreme 9 anchors of the structure 1, then emerged floats 15 are hung on each of these two extreme anchors 9 as can be seen in FIG. 2. The emerged floats 15 are installed for tracking purposes and are typically buoys. Subsequently, the intermediate anchors 9 are fixed between the extreme anchors 9 at the level of each marking. A submerged float 13 is installed about 5m from the seabed on each intermediate anchor 9, then the rope is finally recovered.

The ground preparation of the structure 1 begins with the adjustment of the length of the chains 7 according to the arrangement of the anchors 9. Then, a mooring collar 117 is fixed by tightening with a screw and a nut in the bore 121 on each pillar 2 near each end 3 and 5. Thereafter, a compressor is prepared to fill the internal cavity 115 with air. Keying devices are placed on shackles 11, typically paints of different colors, in order to facilitate the installation of structure 1. Finally, a ballast is prepared to facilitate the immersion of structure 1.

The launching begins with the opening of the two valves 107 and 109 of the pillar 2 to allow the pair to be driven out of the cavity 115 of the pillar 2 during its descent. Then the structure 1 is ballasted at the end 3 of the pillar 2 to make it flow.

Structure 1 is then immersed. Once the structure 1 is substantially at the bottom of the skin, the free end of each chain 7 is fixed to a shackle 11 of an anchor 9. Then, the internal cavity 115 is filled with air with the compressor by one of the two valves 107 or 109, the other valve serving to evacuate the Water until the desired buoyancy is obtained. Finally, the compressor is stopped and the two valves 107 and 109 of the pillar 2 are closed. The valve 107 is closed and opened by a bottom operator, for example a plunger.

The operating cycle of the shellfish farming structure takes place in two stages: the installation of the juveniles on the structure 1 and their harvest at maturity.

In order to implant the juveniles on pillar 2, ropes of juvenile mussels are made with cotton netting for sowing. These ropes are then transported by boat to the concession and reared by a diver by surrounding them around pillar 2. The mussel rope can be held in pillar 2 with elastics, ropes or any equivalent device allowing to maintain the string of mussels around pillar 2. After a few days, the cotton net will decompose, allowing the mussels to attach to the support. A protective net against predation can be installed (jacketed) around the device, like a cover with spacers to facilitate implementation on pillar 2 and thus have sufficient rearing space for the growth of the product.

During the harvest, the shellfish product is recovered by a bottom operator, typically divers, reassembled on a ship and repatriated ashore. This harvest decreases the weight supported by structure 1. Conversely, the growth of molluscs increases this weight. In order to manage these variations in weight, the buoyancy of the pillars can be adjusted.

In a first embodiment called "minimal swelling" the desired buoyancy is such that the pillar 2 is in the vertical position. In this case, it is necessary to carry out regular maintenance of the buoyancy of the structure 1 to maintain sufficient buoyancy throughout the life of the structure 1.

This buoyancy adjustment is done in three stages: the valves 107 and 109 are open, then air is injected through the valve 109 with a compressor (the water escaping through the valve 107), and finally the valves 107 and 109 are closed when there is sufficient buoyancy again.

In a second embodiment, called "overinflation", the internal cavity 115 is filled with air in order to achieve a buoyancy of the structure 1 much greater than that necessary for a structure without any additional weight fixed (that is to say say without juvenile or shell attached to the pillar 2). The swelling, that is to say the amount of air necessary to arrive in the desired buoyancy state, is dimensioned so that the structure I can support a weight for example of a few quintals corresponding to the maximum weight of molds attached to structure 1 during a culture cycle. This swelling eliminates the need to carry out maintenance of buoyancy during installation and then the growth of juveniles.

A major advantage of the invention is that it can be made safe in the event of a strong disturbance, for example storms. This has the effect of temporarily sheltering structure 1 at the bottom of the water, in order to limit the losses due to the disturbance. To do this, pillar 2 is filled with water using valves 107 and 109, so that the structure 1 π

sinks to the bottom of the aquatic environment. Once the storm has passed, the swelling operation is repeated, either according to the "minimum swelling" embodiment or according to the "over-swelling" embodiment.

It is perfectly possible to change the embodiment between the “minimal swelling” mode and the “swelling” world between before and after a safety device or at any other time during the operation of the structure 1.

In the embodiment of Figure 7, the valve 107 and / or the valve 109 are integrated 10 inside the cavity 115 of the pillar 2, respectively in the portion located between the plug 101 and the end of the pillar 2 , while a window is provided in the wall of the pillar 2 in order to allow access to the valve 107 and / or 109.

Claims (15)

1. Self-floating shellfish farming structure, comprising a pillar (2), substantially cylindrical, characterized in that the structure comprises at one of the ends of the pillar a clip suitable for being fixed to an aquatic bottom, and in that the pillar ( 2) has an internal cavity and is provided with at least two valves (107, 109) each arranged in the vicinity of a respective end of the pillar and allowing access from the outside of the pillar to the cavity for filling and at least partially empty a fluid with a density lower than that of water. 2. Self-floating shellfish farming structure according to claim 1, characterized in that the pillar (2) comprises a cylindrical tube closed by a plug (101) at each of its ends. 3. Self-floating shellfish farming structure according to claim 2, characterized in that the pillar (2) comprises several elementary cylindrical tubes (103) interconnected by sleeves (105). 4. Self-floating shellfish farming structure according to one of the preceding claims, characterized in that the attachment capable of being fixed to an aquatic bottom comprises two chains (7) each fixed to the bottom by an anchor (9) with respective screws. 5. Self-floating shellfish farming structure according to claim 4, characterized in that it comprises a mooring collar (117) fixed by clamping around the side wall of the pillar (2), this mooring collar (117) having two attachment points of said chains (7) connecting the pillar to the seabed. 6. Self-floating shellfish farming structure according to one of the preceding claims, characterized in that the pillar cavity (1) is occupied by air. 7. Self-floating shellfish farming structure according to one of the preceding claims, characterized in that the internal cavity (115) of the pillar (2) occupies a major part of the volume of the pillar (2). 8. Self-floating shellfish farming structure according to one of the preceding claims, characterized in that at least one float (13, 15) is associated with the fastener. 9. Self-floating shellfish farming structure according to one of the preceding claims, characterized in that it comprises a device for protection against predation by a net covering the entire structure. 10. Method for operating a self-floating shellfish farming structure, comprising the following operations: a) Provide a substantially cylindrical pillar (2) and comprising at one end of the pillar a clip suitable for being fixed to an aquatic bottom, an internal cavity, and two valves (107, 109) each arranged in the vicinity of a respective end of the pillar, allowing access from the outside of the pillar to the cavity to fill and empty it, b) Lower the pillar (2) into the water and attach it to the water bottom, c) Fill the pillar with a fluid density lower than that of water. 11. Method according to claim 10, characterized in that operation b) is carried out by means of two chains (7) each fixed to the bottom by a respective screw anchor. 12. Method according to claim 11 characterized in that operation b) is carried out by tightening a mooring collar (117) around the pillar (2) and the attachment of chains (7) to the collar mooring (117). 13. Method according to one of claims 10 to 12, characterized in that operation c) is carried out with air as a fluid with a density lower than that of water. 14. Method according to one of claims 10 to 13, characterized in that operation c) comprises: cl) The opening of the valves (107, 109); c2) Injection of the fluid through the valve (107) closest to the surface of the water; c3) The closure of the valves (107, 109) when a desired buoyancy is obtained. 15. Method according to one of claims 10 to 14, characterized in that it further comprises the following operation: d) using the valves (107, 109), fill the pillar (1) with water so that the structure sinks to the bottom of the aquatic environment.