NL2016073A - Device and method for collecting and/or growing aquatic animals. - Google Patents

Abstract

A device for collecting and/or growing aquatic animals, comprising an outside (1) that extends at least partially around an inner cavity, wherein the outside has a plurality of openings into the inner cavity, wherein the inner cavity contains an inner structure (2) , and wherein the device comprises one or more of a textured surface at the outside, a textured surface at the surface of the inner structure, a secondary inner structure (3) that supplements the inner structure wherein the secondary inner structure has a textured surface, wherein the provided textured surfaces are capable of cultching spat, seed or larvae from the aquatic animals.

Description

Title: Device and method for collecting and/or growing aquatic animals

The present invention relates to a device for collecting and/or growing aquatic animals and to a method for collecting and/or growing aquatic animals. The invention further pertains to the development of natural reefs for aquatic animals, in particular mussel banks, for nature restoration purposes.

Aquaculture techniques aim at breeding and rearing aquatic animals. Its goals are to provide for aquatic animals as a source for food or feed, but also to prevent the loss of habitat for aquatic animals in natural waters. Habitats for aquatic animals are increasingly at risk due to human intervention (e.g. excessive fishing, habitat destruction, pollution and/or recreational purposes), but are also likely to suffer from natural disasters like storms. Hence there is a continuous need for improving aquaculture techniques and devices to facilitate the breeding and rearing of aquatic animals, not only for commercial purposes, but also for conservation and restoration of nature, such as the development of (semi) artificial reefs.

Typically such structures are porous, two or three- dimensional structures of meshed material such as gaze or wire that allow the aquatic animals to settle and grow on the structure in a relative enclosed environment wherein water and food can freely flow in and out, whilst predators are kept out. Many of these structures are known , also in biodegradable form.

Such structures and devices are known, amongst other from applicants own patent NL2007667. Other structures for providing habitat and culturing aquatic animals are known from W02006/012670 and W02004075633. These structures are known for growing aquatic animals of a variety of species and in a variety of environments.

When aquatic animals such as mussels reproduce, typically fertilization occurs outside the body, with a larval stage that, after being adrift for a certain period, settles on a hard surface.. There, it is capable of moving slowly by means of attaching and detaching byssal threads to attain a better life position.

The known structures appear to be less effective when it comes to initiating the first settlement of some aquatic animals of particular interest (e.g. mussels), i.e. allowing the larvae to settle on the surface. The present inventors found that, while the structures such as disclosed in NL2007667 are capable of catching and growing of aquatic animals, the initial phase, inoculating the structure with seeds and/or larvae and/or spat from the aquatic animal is flawed or delayed. This delay is a disadvantage since, in particular when biodegradable structures are used, the structure itself will degrade and the resulting reef or musselbank will have to rely on its own structure. Therefore, a speedy and complete start is highly advantageous for the generation of artificial reefs and musselbanks.

The present inventors have found that these disadvantages can be overcome and the settling of aquatic animals can be improved when a surface is provided that allows the seeds and/or larvae and/or spat to attach or cling more readily to the surface. By increasing the rate and amount of settled seeds and/or larvae and/or spat on an artificial reef structure, the mussel bank or reef will grow more quickly which is considered as advantageous.

Thus, the invention pertains to a device for collecting and/or growing an aquatic animal, comprising an outside (1) that extends at least partially around an inner cavity, wherein the outside has a plurality of openings into the inner cavity, wherein the inner cavity contains an inner structure (2), and wherein the device comprises one or more of: - a textured surface at the outside; - a textured surface at the surface of the inner structure; - a secondary inner structure (3) that supplements the inner structure wherein the secondary inner structure has a textured surface or is fibrous, wherein the provided textured surfaces are capable of cultching spat, seed or larvae from the aquatic animal. A schematic representation is provided in Figure 1, where the outside (1) has openings into the inner cavity that contains an inner structure 2. The inner structure may be supplemented with a secondary structure 3. The outside can also be formed by the outside of the inner structure (2), for instance in the case of a mesh material such as depicted in the Figure. Alternatively, the outside can be in the form of perforated surfaces such a splates and the like. An aquatic animal in the sense of the present invention is an animal that respires predominantly under water or in the intertidal. In the terms of the present invention, such an animal can be a bivalve such as a scallop, mussel, oyster, or clam. In a preferred embodiment, the aquatic animals are shellfish, preferably from the phylum Mollusc, more preferably the class bivalvia, even more preferable fresh or salt water bivalves. The device of the present invention provides a habitat structure such that the device provides a site within, on or around which the aquatic animals may live, reside, breed and/or be reared. The device is advantageously designed such that it meets the habitat requirements of the animals that are to be grown, reared or kept in the device. One of the advantages of the present device is that, among others due to its structural features, it is capable of providing protection to the aquatic animals from predatory animals. The device according to the invention has an outside that extends or encompasses at least partially around an inner cavity. The device has a three-dimensional structure. The inner cavity is preferably substantially defined and limited by the dimensions of the outside. The outside may extend around the entire inner cavity. For example, a device in the form of a hollow sphere may be considered to have one outside extending wholly around the inner cavity. An elongated tube profile open at both ends may have one outside extending around the inner cavity. A rectangular construct, for instance a block, may be seen as an outside substantially defined by one or more walls that enclose the inner cavity. The shape, size and wall may hence vary considerably, depending on the application of the structure.

The outside has at least one opening into the inner cavity. The opening may be provided by the outside not completely encompassing the inner cavity or may be provided by for instance the presence of openings (holes) in the outside. For example in a tube, openings are provided by both open ends or by providing openings (holes) in the tube profile. The openings serve to provide water and food to the aquatic animals contained in and on the device. The openings also serve to allow the aquatic animals to enter (inoculate) and exit through the openings. Preferably, the openings have a shape and dimension such that the aquatic animals may enter and exit at will, while at the same time predators such as fish, crabs and birds are substantially kept out of the structure. In certain embodiments, the openings independently vary from about 5 millimetre to about 250 millimetre, preferably from about 10 millimetre to about 150 millimetre, more preferably from about 15 to about 100 millimetre and even more preferred form about 20 millimetre to about 50 millimetre. The shape of the openings is not critical and may be round, pyramidal, square, oblong etc. and the openings may each be of a different shape or size.

In one embodiment, the inner cavity contains a structure. Preferably, the structure is a three-dimensional structure and more preferably is not a substantial two-dimensional structure. The three dimensional structure is preferably such that the predators have no access to the internal structure of the device and may have only limited access to the outside. The structure may serve to provide structural strength to the device. The structure may be suitable for housing the aquatic animals in the sense that they may attach to the inner structure and use the structure. The structure may be in the form of a (three-dimensional) mesh or plates, wires, ropes etc. In certain embodiments, the outside and the inner structure may be from the same material or be indistinguishable from each other, for instance when a three-dimensional mesh material is used. The material can be a porous material, preferably in one piece, that has an outside made from mesh material and preferably an inner structure made from (preferably the same) mesh material. The material preferably has a structure that provides it with a certain strength so it can maintain itself. An example thereof is a honeycomb structure. The outside is formed by the outside dimensions of the material and the inner structure by the inside of the mesh material. The openings are provided by the pores of the porous material. A material that has been used with good result is a filter material that is known from its application in aquaculture. An example is a porous polypropylene material having a hexagonal mesh that extends in three dimensions, thus forming a porous body with pore diameters in the range of 5 mm to 50 mm. Such a material can for instance be obtained from Fleuren en Nooijen bv, Nederweert, The Netherlands.

The material from which the outside and/or the inner structure are made are preferably from a polymer material, preferably a thermoplastic polymer, wherein the polymer is selected from the group consisting of polyolefins, polyesters, biodegradable polymers and mixtures thereof. In certain embodiments, the polymer is selected from the group consisting of polyolefins, polyesters, biodegradable polymers and mixtures thereof and wherein (a) the polyolefins are selected from the group consisting of polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polybutene-1 (PB-1) and mixtures thereof; and/or (b) the polyesters are selected from the group consisting of polyglycolide (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate( PHA), Polyethylene terephtalate (PET), polybutylene terephtalate (PBT) and mixtures thereof; and/or (c) the biodegradable polymers are selected from the group consisting of polyvinyl alcohol, starch polymers such as corn starch, potato starch, tapioca starch, high amylose starch and mixtures thereof.

The device may be weighed down, for instance using weights or ballast to position it into location underwater. Devices may be interconnected to provide for lines or rows of devices. The device according to the invention preferably maintains at least 80 % of its structural integrity for at least about 12 to 36 months in an aquatic environment, preferably a freshwater environment. When the structure is capable of disintegrating over time in the environment, for instance because it is made from a biodegradable material, it is not necessary to remove it. This can be an advantage.

The device according to the invention can basically have any shape or form. In certain embodiments, the device has a shape selected from the group consisting of rectangular, square, oblong, spheroid, tube.

In order to contain an adequate number of aquatic animals for the desired purpose (whether growing, rearing, filtering etc.), it is preferred that the device has certain dimensions. By providing the device with dimensions that are large enough for the aquatic animals to enter whereas predators can only predate to a limited extent, the aquatic animals have a safe harbour to life and proliferate. At the same time, the dimensions are preferably such that the animals are in close enough contact with water and food. In practice, it has been found that such a structure is inhabited by aquatic animals, for up to 30 cm, preferably up to 15 cm. The depth may vary with the type of aquatic animal and may also vary with the dimensions of the openings (larger openings facilitate deeper inhabitation). Deeper inhabitation is rare, (albeit not impossible, for instance in faster running waters), due to restraints to the migration of water (oxygen) and food. Hence there is a balance between the depth of inhabitation on one hand and oxygen and food supply on the other hand. To this end it is preferred that the device has dimensions that can accommodate these requirements. In one embodiment, the device has a thickness or diameter that is more than 25 cm, measured over the smallest possible distance. In one embodiment, it is preferred that the device has dimensions such that the shortest distance from a point located in the inner structure to the outside is at least 7 cm, preferably at least 10, more preferably at least 15 cm. Larger distances are possible but are less preferred as they tend to result in uninhabited regions or require larger openings which allows predators to penetrate deeper. For example, this would accommodate a rectangular three-dimensional (block type) structure of indeterminate width and/or length but a height of at least 20 or 30 cm. Or a tube structure of any length, but with a diameter of at least 20 or 30 cm. The device of the invention may also be used to make larger constructions by linking or stacking. For instance, a 3 by 3 stack of blocks can be made with the middle one removed and positioned in either vertical or horizontal position. Good results have been obtained with structures of 0,9mx0,45mx0,3m weighing 3 kg of polypropylene mesh material. Preferably the inner structure is a regular structure and/or is distributed substantially even over the space encompassed by the outside. In other words there are preferably no ‘local’ concentrations of inner structures in the space encompassed by the outside.

The structure of the material can also be defined by the percentage of void space, i.e. the percentage of the space encompassed by the outside and not occupied by the inner structure. It is preferred that the structure is substantially hollow, i.e. is void. It is preferred that, of the non-inhabited structure, at least 75%, more preferably at least 85%, more preferably at least 90% is not occupied by the inner structure. Put differently, in a preferred embodiment, the inner structure is at most 25%, more preferably at most 15% and most preferably at most 5% of the volume encompassed by the outside.

The device has a surface that at least in part is a textured surface. Textured surface in this respect means that the surface is uneven, not smooth, rough, or fibrous, as is easily perceived by touching. In the present invention, the textured surface may be at present in a number of independent (hence combinable) embodiments. A textured surface can be achieved by a post-formation treatment of the initial surface or is formed while forming the initial surface. The surface of the device may be textured at the outside. Also or alternately, the surface of the inner structure of the device may be textured. The surface may be provided with a texture capable of cultching spat, seed or larvae from the aquatic animal by physical attrition methods such as sanding or roughing, i.e. by subjecting the structure to attrition forces such as sand blasting and/or sanding the outside and/or inner structure to provide for the textured surface.

In a more preferred embodiment, the provision of textured surfaces that are capable of cultching spat, seed or larvae from the aquatic animal can be achieved by equipping the surface with providing the outside and/or inner structure with particulate or fibrous solid structural elements such as sand, calciumcarbonate, hydroxyapatite, crushed shells, glass, glass wool, rock wool, yarns, fibers to provide for the textured surface. These structural elements may be attached to the surface by glue or otherwise provided such as by coextrusion of the material of the structure with the structural elements etc.

In a more preferred embodiment, a secondary inner structure may be provided. The secondary structure supplements the inner structure. The secondary structure provides a structural element that is capable of cultching spat, seed or larvae from the aquatic animal. The secondary structure may be physically attached to the inner structure or to the outside, for instance by tie wraps, but it nevertheless forms a structure of its own. The secondary inner structure can be in the form of yarns, fibers, fabric, ropes, or cloth to provide for the textured surface. It can be intermingled or intertwined with the inner structure or the outside. For instance in the case of a mesh extruded thermoplastic, it can be a sisal rope or strip run through the holes of the mesh. It can be in the form of strips or ropes etc. The material is preferably a biodegradable material and is preferably more biodegradable than the material of the inner structure and/or the outside. Biodegradable in terms of the present invention implies that the material is no longer capable of performing its intended function (loss of structural integrity and capability of supporting aquatic animals) after a period of two to 10 years for the outside and/or the inner structure. The secondary structure preferably has a biodegradability that is about 20-40% of the biodegradability of the outside and/or the inner structure, i.e. 20% of two to ten years.

The invention further pertains to a method for collecting and/or growing an aquatic animal comprising the steps of providing a device as defined hereinbefore, contacting the structure with an aqueous environment, allowing the device to become inoculated with seed and/or larvae and/or spat from the aquatic animal (cultching), and optionally, allowing the seed and/or larvae and/or spat from the aquatic animal to grow into larger aquatic animals, preferably attached to the device. The inoculation may be performed at a first location whereas the subsequent growing may be performed at a second location. This would be interesting for the commercial growth of aquatic animals. Alternatively, inoculation and growth may occur at one place, for instance for the generation of musselbanks and reefs etcetera.

Thus, the device as described herein above is brought into a first aqueous environment, preferably an environment that contains, or at least is suspected to contain, aquatic animals, and/or their seed and/or larvae and/or spat.

The structure is allowed to become inoculated with the aquatic animals, and/or their seed and/or larvae and/or spat. Typically, this is achieved by submerging it in the water for a period of time (days or weeks) in the right season (species dependent). The seed and/or larvae and/or spat attach themselves to the outside and/or the inner and/or the secondart structure structure. The young bivalves can be allowed to grow/develop on the structure for a period of time until they are grown enough to be retrieved from the first aqueous environment.

Retrieval of the inoculated structure can be achieved relatively easy when the device according to the invention is used. The device can simply be lifted from the bottom of the water body by a crane or other devices, or brought to the surface by floating. The device is such that it can be transported over a distance and over a period of time without damaging the structure or the (young) aquatic animals. The device containing the aquatic animals (whether very young or more grown), can be transported to another place. The other place can be a second aquatic environment (water body), but can also be the same aqueous environment but at a different location. There is a preference to culture the aquatic animals first (prior to moving), so large quantities can be introduced in water bodies without significantly damaging the population of aquatic animals elsewhere. Alternatively, the inoculated structures, after being retrieved from the first aquatic environment can be cultured elsewhere before being placed in the second aqueous environment. Aquatic environments or water bodies as used herein refer to seas, coastal lines, estuaries, lakes, ponds, rivers, streams etc.

In a further aspect, the present invention relates to a method for the development of a natural reef comprising proving a device as defined herein, wherein the structure-forming material of the outside and/or the inner structure comprises a biodegradable polymer and wherein the structure maintains at least 80 % of its structural integrity for about 12 to 36 months in an aquatic environment. In this aspect of the invention, a structure or device can be already available and can be a construction as outlined herein elsewhere. The structure can be inoculated and/ or grow aquatic animals, essentially as outlined herein before. The structure over time will deteriorate, leaving the aquatic animals that by now have grown and form their own support structure that over time can develop into a natural reef.

CLAUSES 1. A device for collecting and/or growing an aquatic animal, comprising an outside that extends at least partially around an inner cavity, wherein the outside has a plurality of openings into the inner cavity, wherein the inner cavity contains an inner structure, and wherein the device comprises one or more of: - a textured surface at the outside; - a textured surface at the surface of the inner structure; - a secondary inner structure that supplements the inner structure wherein the secondary inner structure has a textured surface or is fibrous, wherein the provided textured surfaces are capable of cultching spat, seed or larvae from the aquatic animal. 2. Device according to clause 1, wherein the textured surface is provided by one or more of a secondary inner structure in the form of yarns, fibres, ropes, fabric, cloth to provide for the textured surface; - texturing the outside and/or inner structure by subjecting the structure to attrition forces such as sand blasting and/or sanding the outside and/or inner structure to provide for the textured surface; - providing the outside and/or inner structure with particulate or fibrous solid structural elements such as sand, calciumcarbonate, hydroxyapatite, crushed shells, glass, glass wool, rock wool, yarns, fibers to provide for the textured surface; - providing a material for the outside and/or inner structure that is a mixture of particulate or fibrous solid structural elements and structure-forming material. 3. Device according to clause 1 or 2, wherein the structure-forming material is present in an amount of at least 30 wt%, drawn on the material mixture. 4. Device according to clauses 1-3, wherein the outside and/or the inner structure is the form of substantially rigid or self-supporting mesh or webbing. 5. Device according to clauses 1-4, wherein the outside and/or the inner structure is in the form of a tubular mesh structure, a modular tray structure or a flat hinged or envelope mesh structure. 6. Device according to clauses 1-5, wherein the inner cavity is for at most 25 % occupied by the inner structure. 7. Device according to clauses 1-6, wherein the inner structure and/or the outside have a (three-dimensional) structure selected from the group consisting of mesh, plates, wires, ropes, tubes, boxes, balls, poles and combinations thereof. 8. Device according to clauses 1-7, wherein the outside and/or the inner structure independently have openings ranging from about 5 millimetre to about 25 centimetre. 9. Device according to clauses 1-8, wherein the device has a rectangular, square, oblong, spheroid or tube shape. 10. Device according to clauses 2-9, wherein the structure-forming material of the outside and/or the inner structure are made from a polymer material, preferably a thermoplastic polymer, wherein the polymer is, independently, selected from the group consisting of polyolefins, polyesters, biodegradable polymers and mixtures thereof. 11. Device according to clause 10 wherein a. the polyolefins are selected from the group consisting of polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polybutene-1 (PB-1) and mixtures thereof; and/or b. the polyesters are selected from the group consisting of polyglycolide (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxyalkanoate( PHA), Polyethylene terephtalate (PET), polybutylene terephtalate (PBT) and mixtures thereof; and/or c. the biodegradable polymers are selected from the group consisting of polyvinyl alcohol, starch polymers such as corn starch, potato starch, tapioca starch, high amylose starch and mixtures thereof. 12. Device according to clauses 1-11, wherein the structure maintains at least 80 % of its structural integrity for about 12 to 36 months in an aquatic environment. 13. Device according to clauses 1-12, wherein the aquatic animal are shellfish, preferably from the phylum Mollusc, more preferably the class bivalvia, even more preferable scallops, oysters, molluscs, clams. 14. Device according to clauses 1-10, wherein the outside encloses the inner cavity. 15. Method for collecting and/or growing an aquatic animal comprising the steps of providing a device as defined in any of the previous clauses, contacting the structure with an aqueous environment, allowing the device to become inoculated with seed and/or larvae and/or spat from the aquatic animal (cultching), and optionally, allowing the seed and/or larvae and/or spat from the aquatic animal to grow into larger aquatic animals, preferably attached to the device. 16. Method for the development of a natural reef comprising proving a device as defined in clauses 1-14, wherein the structure-forming material of the outside and/or the inner structure comprises a biodegradable polymer and wherein the structure maintains at least 80 % of its structural integrity for about 12 to 36 months in an aquatic environment.

Claims (16)

An apparatus for collecting and / or growing an aquatic animal, comprising an exterior that is at least partially located around an interior cavity, the exterior having a plurality of openings to the interior cavity, the interior cavity including a first interior structure, and wherein the device comprises one or more of: - a textured surface on the outside; - a textured surface on the surface of the inner structure; - A second inner structure that complements the first inner structure, wherein the second inner structure contains a textured surface or is fibrous, the textured surfaces being capable of causing breeding, seed or larvae of the aquatic animals. Device as claimed in claim 1, wherein the textured surface is provided by one or more of - a second inner structure in the form of wires, fibers, cables, fabric, cloth for the textured surface; texturing the outside and / or inside structure by subjecting the structure to attention forces such as sandblasting and / or sanding the outside and / or the inside structure to provide the textured surface; - providing on the outside and / or on the inside structure of particulate or fibrous solid building elements such as sand, calcium carbonate, hydroxyapatite, crushed shells, glass, glass wool, rock wool, yarns, fibers to give the textured surface; - Providing a material for the outside and / or inside structure of a mixture of particles or fibrous solid structural parts and structure-forming material. Device according to claim 1 or 2, wherein the structure-forming material is present in an amount of at least 30% by weight, based on the material mixture. Device as claimed in claims 1-3, wherein the outside and / or the internal structure take the form of substantially stiff or self-supporting mesh or fabric, Device according to claims 1-4, wherein the outside and / or the internal structure is in the form of a tubular mesh structure, modular box structure or a flat hinged or envelope mesh structure. Device as claimed in claims 1-5, wherein the internal cavity is occupied by a maximum of 25% by the inner structure. Device according to claims 1-6, wherein the internal structure and / or outside is a (three-dimensional) structure selected from the group consisting of mesh, plates, wires, cables, tubes, boxes, balls, posts and combinations thereof. Device as claimed in claims 1-7, wherein the outside and / or the inside structure contains openings independently of each other ranging from approximately 5 mm to approximately 25 centimeters. Device according to points 1-8, wherein the device has a rectangular, square, elongated, spherical or tubular shape. Device as claimed in claims 2-9, wherein the structure-forming material from outside and / or inside structure is made of a polymer material, preferably a thermoplastic polymer, wherein the polymer is independently selected from the group consisting of polyoifins, polyesters, biodegradable polymers and mixtures thereof. The device of claim 10, wherein a. The polyoefins are selected from the group consisting of polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polybutene-1 (PB-1) and mixtures thereof; and / or b. the polyesters are selected from the group consisting of polyglycolide (PGA), polylactic acid (PLA), polycaproactone (PCL), polyhydroxyalkanoate (PHA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and mixtures thereof; and / or c. biodegradable polymers are selected from the group consisting of polyvinyl alcohol, starch polymers such as corn starch, potato starch, tapioca starch, high amyiosis starch and mixtures thereof. The device of claims 1-11, wherein the structure retains at least 80% of its structural integrity for about 12 to 36 months in an aquatic environment. Device as claimed in claims 1-12, wherein the aquatic animal is crustaceans, preferably from the Mollusc strain, preferably the Bivalvia class, even more preferably scallops, oysters, molluscs, mussels. Device according to claims 1-10, wherein the outside encloses the internal cavity. Method for collecting and / or growing an aquatic animal comprising the steps of providing a device according to any one of the preceding claims, bringing the structure into contact with an aqueous environment, so that the device is inoculated with seed and / or larvae and / or aquatic animal breeding (cultching), and optionally, growing the seed and / or larvae and / or aquatic animal breeding into larger aquatic animals, preferably attached to the device. A method for developing a natural reef comprises a device according to claims 1-14, wherein the structure-forming material of the outside and / or the inside structure is a biodegradable poiveer and wherein the structure retains at least 80% of its structural integrity for about 12 to 36 months in a water-rich environment.