WO2019135055A1 - Method for oyster farming - Google Patents

Abstract

The invention relates to a method for oyster farming, comprising the following operations: anaesthetising the oyster (1) in a sterile medium; separating the valves (2, 3) of the oyster (1) in a sterile medium; introducing a pearl (7) into the mantle cavity or the hepatopancreas of the oyster (1) in a sterile medium; immersion in a revival bath until the valves (2, 3) close, in a sterile medium; transferring the oyster (1) in an individual cell into a monitoring pond; and then returning the oyster into the farming system.

Description

 Oyster farming process

The invention relates to the field of oyster farming.

Oyster culture is a traditional and complex field that has changed little over time. Traditionally, oysters are reared in an uncontrolled manner, either directly on the ground or in devices such as submerged pockets in the wild or baskets or lanterns. In some areas, oysters are stuck with cement on ropes or bars.

The Applicant has already developed several innovations for the purpose of modernizing and improving the zootechnie oyster. For this purpose, it has for example proposed in FR 3,019,967 an oyster culture process that greatly improves the organoleptic qualities of oysters.

Furthermore, WO2004 / 064562 discloses a method of sintering pearl nucleus comprising grinding, forming a green part and sintering proper. These operations are slow. The final result is random for both the quality and the actual pearl presence.

The Applicant aims to create the possibility of providing oysters consumption high pearl rate and guaranteed. This need was non-existent because of the lack of pearls in the oysters and the fact that this absence was an established fact. Pearls production was a distinct industry using different bivalves, of the order Pterioida, called oysters for ease of language, in different places and with different constraints and requirements.

The invention improves the situation.

The invention provides an oyster farming method comprising the following operations:

 - anesthesia of the oyster in a sterile environment,

 - spacing of the oyster valves in a sterile environment,

 - introduction of a pearl into the oyster's pallial cavity in a sterile medium,

- immersion in a wake-up bath until the valves close, in a sterile environment, - Transfer of the oyster to an individual cell in a monitoring pond, then

- return to breeding.

The presence of a pearl becomes very likely instead of being rare and random.

In one embodiment, the method comprises a prior step of selecting the oyster according to the size. Too small a template results in a high rejection risk. Too high a caliber translates into a short-term marketing does not leave the oyster time to form new layers of pearl on the pearl.

In one embodiment, the method comprises a prior step of selecting the oyster according to at least one of: color, shape, undulations and shell hardness. The shape and the undulations are such that they leave enough space for the nucleus or pearl. The shell provides sufficient hardness to ensure proper growth of the pearl.

In one embodiment, the method comprises a prior step of polishing the oyster to be anesthetized. The polishing improves the texture of the outer shell and gives a non-cutting character to the animal, especially around the periphery of the two valves, for its gripping for opening. Polishing improves cleanliness / surface hygiene by abrasive removal of organic surface pollution, including organic matter, bacteria, microalgae encrusting diatom type.

In one embodiment, the method comprises a step of introducing a disconnecting wire pulling tool between the mantle of the upper valve and the upper valve, a step of pulling the disconnecting wire by the tool, and a step traction of the thread for adaptation of a loop of wire to the diameter of the adductor muscle. The disconnecting wire can be located at the level of the adductor muscle. The pull of the thread is light to allow the free adductor muscle to function between the open position and the closed position of the shell valves. It is thus possible to prepare an opening wire of the oyster to facilitate its opening before consumption.

In one embodiment, the oyster is of the genus Crassostrea and the species Crassostrea Gigas, or of the genus Saccostrea or another kind of hollow oyster consumption. The species Crassostrea Gigas is proving to be particularly suitable for pearl introduction. Alternatively, the oyster is a kind of flat oyster consumption.

In one embodiment, the method comprises a prior step of cleaning the shell of the oyster to be anesthetized. The risk of oyster pollution is reduced. The risk of accidental introduction of impurities into the oyster is reduced.

In one embodiment, the method comprises a prior step of exuding the oyster for a period of between 1 and 5 hours, immediately before anesthesia. The exondation causes a filtration stop, then during the release in the anesthetic bath, the filtration recovery stronger than the current filtration enhances the absorption of the anesthetic.

In one embodiment, the anesthesia comprises immersion in an anesthetic bath. The anesthetic bath may comprise an anesthetic product diluted in a mixture of fresh water and seawater, preferably in a mixture of 40 to 80% freshwater and 20 to 60% seawater.

In one embodiment, the spacing of the valves comprises the introduction of forceps, the maneuvering of the forceps in spacing, the forceps being removed after the installation of the bead. Optionally, is provided the installation of a wedge spacer, the wedge being removed after the installation of the bead. The forceps can be removed after laying the hold. Forceps and wedge are made of materials chosen for their non-aggressiveness vis-à-vis the oyster. The spacing can be up to about 20 mm.

In one embodiment, immersion in the wakeup bath includes positioning the hinged oyster at the bottom. Said positioning avoids the rejection of the pearl or nucleus when the oyster is still asleep open valves.

In one embodiment, the method comprises a subsequent step of placing the oyster in an individual cell in a monitoring pond. The eventual rejection of the pearl is monitored. In one embodiment, the bead is made of mother-of-pearl from selected oyster shells, for example oysters raised in controlled exfaction. For this purpose, the oyster shells are crushed and then agglomerated to the desired size.

Other characteristics and advantages of the invention will appear better on reading the description which follows, examples given by way of nonlimiting illustration, taken from the drawings in which:

 - Figure 1 is a schematic view of the opening step of the oyster,

 FIG. 2 is a schematic view of the step of introducing a pearl,

 FIG. 3 is a schematic view of the step of embossing the upper mantle,

 FIG. 4 is a schematic view of the step of positioning the wire,

 FIG. 5 is a schematic view of the setting stage, and

 - Figure 6 is a schematic view of the clamping step of the loop.

The drawings and the description below contain, for the most part, elements of a certain character. They can therefore not only serve to better understand the present invention, but also contribute to its definition, if any.

During her research, the Applicant has found that it is very difficult to influence the oyster form factor. She also found that it is very difficult for consumers to confidently identify the oysters they buy. Indeed, apart from their confidence in the labeling of the hamper and the knowledge for a very limited number of consumers of the taste qualities of the different oysters, it is not possible to confidently qualify the provenance of an oyster.

To solve these problems, the Applicant invented an oyster culture support described in patent FR 3,022,106. When the portion receiving the oysters is concave, the Applicant has found that oysters adopt an unnatural form factor. In fact, in the wild, when oyster larvae catch on a rock, they develop by following the shape of the rock. It has therefore sought to use supports whose surface is generally flat, to allow oysters to develop in their natural form.

As has been described in patent FR 3,022,106 the brand has the advantage that the oyster, growing up, comes to marry its shape, and naturally engrave the negative of the mark in its shell. Thus, in the example described here, the shell of the oyster will have a rib about 0.5 mm in height, with the letters H and T in uppercase letters.

The invention described in patent FR 3,036,581 proposes an oyster culture support, which has a body having a portion for rearing an oyster, which portion is substantially flat and comprises an oyster attachment zone juvenile and at least one hole opening on either side of the body away from said attachment zone, so that the oyster hooks on the support at said hole during its growth.

This type of support is very advantageous because the oyster, growing up, can grow through the hole and form a shell rivet that passes through the body of the support. Thus, the oysters are firmly attached to the support and are no longer lost. In addition, the rivet is crystallized calcium carbonate (CaCO3) (calcite and aragonite), it is relatively easy to break by shear stress, which makes the harvest much easier.

With support, oysters can therefore grow with a natural form factor, while being marked if the portion has a mark. Thanks to the rivets formed by the glue or the oyster, the attachment to the support is greatly improved, and little or no oysters are lost during breeding. In addition, thanks to the optional presence of the first set of holes, it is possible to raise in suspension, or in a traditional way.

Thanks to the support, it is possible to implement an oyster culture process in which juvenile oysters are attached to a support according to the invention, and immersed for a period of between 6 months and 48 months. It should be noted that any type of immersion process may be considered, whether it is a culture site with a natural tide, or whether it is a culture site in which there is no natural tide. In particular, the breeding method which is the subject of patent FR 3,019,967 makes it possible, in conjunction with the support, to obtain oysters having exceptional organoleptic qualities.

Such high quality oysters and also oysters of ordinary quality may be the subject of insertion of pearls, a pearl per oyster, a few months before their marketing. As can be seen in the figures, an oyster 1 comprises a first shell or valve 2 and a second shell or valve 3. Inside the shells, see Figure 3, the oyster 1 comprises an adductor muscle 4, a coat upper 5, and a lower coat not visible and associated with the lower shell opposite to the upper shell in contact with the upper mantle. The shells 2 and 3 are articulated by a hinge 6. The hinge 6 allows the natural opening and closing of the oyster 1 during its lifetime, providing an axis of rotation of one shell relative to the other . The adductor muscle 4 causes the opening or closing of the oyster 1. The closure of the oyster allows the conservation of water inside the shells for survival in difficult conditions or during natural lunar tides. or artificial mechanized exondations. The opening of the oyster allows the renewal of water and its nutrient supply.

In the figures, the active hands or hands of the operator have been shown in dashed lines.

The oyster 1 is disposed on a holding support 10. The holding support 10 comprises a foot 11 provided to rest on a surface such as a table, a leg 12 and two jaws 13, 14 hinged provided with a tending spring to close them. The jaws 13 and 14 are opened by an operator and the oyster 1 is disposed between said jaws 13 and 14. Then the jaws 13 and 14 are released so as to slightly tighten the shells 2 and 3 of the oyster 1. L Oyster 1 is thus held in a flexible manner between the jaws 13, 14. The opening of the oyster 1 resulting in a separation of the shells 2 and 3 which is accompanied by a spacing of the jaws 13, 14.

The oyster 1 is opened by means of a forceps 20. The forceps 20 comprises two levers 21,22 hinged about an axis 23 and tensioned by a spring 24. Each lever 21,22 comprises, on the side of the 23 opposite axis to the spring 24, a spatula 25 rounded and thick so that it can be inserted between the shells 2 and 3 in a gentle manner. The forceps 20 also comprises a flange 26 limiting the opening stroke of the levers 21 and 22 and therefore the spatulas 25. By way of example, the distance between the outer surfaces of the spatulas 25 may be limited to 20 mm. The forceps 20 can be made of food grade stainless steel.

A bead 7 can be introduced into the oyster 1 by means of a bead-carrying tool 30. The bead-carrying tool 30 comprises a rod and a bead-holding end capable of taking a bead 7 and releasing it to the will of the operator. The pearl 7 may be a natural or artificial pearl or a nucleus formed from a crushed oyster shells conglomerate.

The oyster 1 is first of all subjected to a selection according to the caliber. Oysters too large or too small are eliminated avoiding a too short breeding time after the contribution of the pearl or an unsuitability of the size of the oyster 1 and the size of the pearl. An additional selection may be implemented depending on the color, shape, ripples and the shell hardness of the oyster. It is indeed not desirable to provide pearls in an oyster that may be subject to a decommissioning or in an oyster whose geometric and / or mechanical characteristics are inappropriate. An oyster 1 with a low risk of pearl rejection based on criteria that can be measured or estimated in a simple manner is selected.

The oyster 1 is subject to external polishing of the shells. Polishing may include cleaning with water, especially in a turbulent bath or water jet or soft brush. Cleaning makes it possible to remove foreign bodies or impurities which are not adherent or not very adherent to the shells. The rest is carried out under sterile conditions.

The oyster 1 cleaned is exfoliated for a chosen period. The duration of exposure can be between 1 and 5 hours. The subsequent anesthesia is made easier.

The oyster 1 is then anesthetized. Anesthesia occurs rapidly after the exonation, preferably without delay other than the time required for transfer or manipulation. In another embodiment, an exonation lasting between 1 hour and 5 hours immediately precedes the anesthesia. Anesthesia takes place in a sterile environment. Anesthesia is performed by immersion in a bath. The anesthetic bath comprises an anesthetic product in a mixture of fresh water and sea water, preferably a mixture of 40 to 80% of fresh water and 20 to 60% of seawater, for example 60% of water. fresh water and 40% of seawater. The immersion in the anesthetic bath can be carried out for a period of between 2 and 6 hours. The anesthetic bath is maintained at a temperature between 10 and 20 ° C. The oxygen level of the anesthetic bath is between 9 and 11 mg / l, in particular by bubbling and circulation of the bath water. The anesthetized oyster 1 is disposed on the holding support 10. The jaws 13 and 14 of the holding support 10 are closed on the oyster 1 providing elastic retention. Then the forceps 20 is introduced between the shells 2 and 3. The forceps 20 is activated by spacing the spatulas 25 to the limit imposed by the flange 26, see Figure 1. The anesthetized oyster 1 offers only a weak resistance to the introduction of the forceps 20 as well as to the spacing of the shells 2 and 3, compared to a non-anesthetized oyster.

A wedge not shown, can then be introduced between the shells 2 and 3. The shim can be in the form of a low slope corner, made of stainless steel or plastic food. The wedge allows the removal of the forceps 20 and makes available one of the hands of the operator.

The oyster 1 is then kept shells 2 and 3 open by the hold - the forceps 20 can then be removed - or forceps 20 remained in place. The oyster 1 is kept in a sterile environment. In Figure 2, the forceps 20 maintains the opening between the shells 2 and 3. A pearl 7 or a pearl nucleus is then inserted into the oyster 1. The pearl 7 is carried by a pearl holder tool 30. The Bead tool 30 is handled by the operator. More precisely, the operator holds the rod of the bead-carrying tool 30 and passes the bead 7 between the edges of the shells 2 and 3. The operator comes to deposit the bead 7 by introducing it into the pallial cavity of the bead. oyster 1, especially between the upper mantle and the lower mantle, and the gills and the digestive gland. The operator removes the bead tool 30 out of the shells 2 and 3. The bead tool 30 is adapted to the gripping of a bead 7 and release controlled by the operator.

As can be seen in FIG. 3, the operator provided with a repelling tool 31 comes to repel the upper mantle 5 of the oyster 1. The upper mantle 5 is the relatively thin portion of the oyster 1 in contact with the one of the shells 2, 3. The lower mantle, also present, is not visible because hidden by the other shell. The spool 31 is in the form of a rod provided with a round end. The round tip avoids hurting the oyster 1, including the upper mantle 5. The spool 31 causes a separation between the upper mantle 5 and the corresponding shell. The adductor muscle 4 retains the bond between the shell and the upper mantle 5.

In the step illustrated in FIG. 4, the operator positions an oyster opening wire 32. The oyster opening wire 32 allows easy opening during the preparation of the consumption of the oyster 1. It is sufficient to pull on the opening wire 32 to sever the adductor muscle 4 and thus open the oyster 1 quickly, safe for the person opening the oyster 1 and reducing the risk of shell breakage.

The operator then acquires a loop pulling tool 33. The loop pulling tool 33 comprises a gripping rod and a hook at one of its ends. The loop pulling tool 33 makes it possible to pass the opening thread 32 around the adductor muscle 4. The operator makes a loop 34 at one end of the opening thread 32. The loop 34 is then passed in the oyster 1. More specifically, the loop 34 of the opening thread 32 is passed to the level of the adductor muscle 4 between the shells 2 and 3. The opening thread 32 may be passed through a operator's gesture similar to the gesture of a suture doctor.

Figure 5 shows the continuation of the positioning of the oyster opening wire 32. The other end of the opening thread 32 is passed through the loop 34. The operator then causes the loop 34 to move towards the inside of the oyster 1, in FIGS. 5 and 6. The loop 34 is positioned closer to the upper shell.

FIG. 6 shows the positioning of the loop 34 in contact with the adductor muscle 4 thus forming a sliding knot 35 around the adductor muscle 4. The sliding knot 35 is thus adapted to the diameter of the adductor muscle 4. A portion of the thread 32 opening is left to overtake shells 2 and 3.

The shim is removed or the forceps 20 are tightened and removed. The oyster 1 is then removed from the holding support 10. The oyster 1 is placed in a waking bath in a sterile medium. The wakeup bath has a composition similar to that of seawater. The wakeup bath may comprise sea water reconstituted by drinking water and an addition of mineral salts, especially at least NaCl. The immersion in a wake-up bath is carried out until the closing of the shells 2 and 3. In general, the duration of immersion in a wakeup bath is between 10 and 24 hours. The wakeup bath is maintained at a temperature of between 10 and 20 ° C. The oxygen level of the waking bath is between 9 and 11 mg / l, in particular by bubbling and circulation of the bath water. In the waking bath, the oyster 1 is positioned hinge 6 at the bottom. The oyster 1 can then be handled in a non-sterile medium. The oyster 1 is placed in a monitoring basin in an individual cell. The possible rejection of the pearl 7 can thus be monitored. The oyster 1 having rejected the pearl 7 previously inserted can then be treated separately, either by putting in the cycle described above to insert a new pearl 7, or reintroduced into a conventional oyster breeding circuit.

The oyster 1 having preserved the pearl 7 is then returned to breeding, preferably in a controlled breeding experiment, for example at the motorized breeding table. The breeding can then last several months, for example from 12 to less than 24 months. In a natural way, the oyster then covers the pearl with new layers of mother-of-pearl.

When opening the oyster 1, the operator or the consumer pulls on the end of the wire 32 thereby causing the tightening of the slip knot 35 to sever the adductor muscle 4. The oyster 1 is then opened by manual separation of the shells 2 and 3. The separation does not offer any particular resistance except the elasticity and the resistance of the hinge. The consumer finds the pearl 7 in the oyster 1 by lifting the upper mantle, whether it comes from a pearl or a nucleus.

The breeding according to the invention is suitable for all types of oysters, whether hollow or flat. In general, oysters belonging to the following species are considered: ANIMAL Rule; MOLLUSC branch; Class BIVALVE; Subclass PTERIOMORPHE; Order OSTREOIDA; OSTREIDAE families; Genres Crassostrea, Ostreola, Saccostrea, and other kinds of hollow oysters or flat oysters.

The breeding is particularly suitable for hollow oysters of consumption, because they are particularly adapted to the introduction of a pearl. This farm is also compatible with flat oysters.

Claims

claims 1. Oyster farming method comprising the following operations:  anesthesia of the oyster (1) in a sterile medium,  - spacing of the valves (2, 3) of the oyster (1) in a sterile medium,  - introduction of a pearl (7) into the oyster's pallial cavity (1) in a sterile medium, - immersion in a wake-up bath until the valves (2, 3) close, in a sterile medium,  - transfer of the oyster (1) in an individual cell in a monitoring pond, then - return to breeding. 2. Method according to claim 1, comprising a prior step of selecting the oyster (1) according to at least one of: caliber, color, shape, undulations and shell hardness, and / or a preliminary step of polishing the oyster (1). oyster (1) to be anesthetized. 3. Method according to claim 1 or 2, comprising a step of introducing a tool (33) for pulling wire (32) disconnector between the mantle (5) of the upper valve and the upper valve, a pulling step wire (32) is cut by the tool (33), and a wire pulling step (32) for matching a wire loop (34) (32) to the diameter of the adductor muscle (4). 4. Method according to one of the preceding claims, wherein the oyster (1) is of the genus Crassostrea and Crassostrea Gigas species, or the genus Saccostrea or another kind of hollow oyster consumption. 5. Method according to one of the preceding claims, comprising a prior step of cleaning the shell of the oyster (1) to be anesthetized. 6. Method according to one of the preceding claims, comprising a prior step of exoneration of the oyster (1) for a period of between 1 and 5 hours, immediately before anesthesia. 7. Method according to one of the preceding claims, wherein the anesthesia comprises immersion in an anesthetic bath. 8. Method according to one of the preceding claims, wherein the spacing of the valves (2, 3) comprises the introduction of forceps (20), the operation of the forceps (20) in spacing, optionally the installation of a wedge spacer, the shim being removed after the bead (7) has been applied, the forceps (20) being removed after the bead (7) has been applied. 9. Method according to one of the preceding claims, wherein the immersion in the waking bath comprises the positioning of the oyster (1), hinge (6) at the bottom. 10. Method according to one of the preceding claims, comprising a subsequent step of placing in individual cell oyster (1) in a monitoring basin.