TECHNICAL SCOPE

The invention relates to multitrophic aquaculture systems and, in particular, to a device which allows the cultivation of a first and second organism as well as a system of nitrogen control.

PRIOR ART

Aquaculture has a very long history. Both algae and filter-feeding animals such as mussels are grown around the world for several thousand years and the number of different cultivation processes are high. Traditionally, in the sea, only one species is grown at a time, whether it be algae or animals, but in freshwater it is more common to combine cultivation of plants and animals, which together benefit from one another and reduce the production effort when two products are obtained from the same cultivation area. An example of this is growing pangasius fish in the rice fields. Aquaponics is a concept for such techniques that co-cultivate fish with plants, mostly vegetables, which works well in freshwater, as the fish's excretion products such as ammonium and faeces act as high quality fertilizers for the plants. In salt sea water, such techniques have historically not been developed, but such techniques have been investigated as a way to increase the return on production in so-called integrated or multitrophic systems. By a multitrophic system is meant to combine two or more species from different trophic levels, such as primary producing plants and filtering animals.

To cultivate aquatic animals or algae on immersed bands is a method that occurs throughout the world and is the dominant method in Swedish waters, termed long-line cultivation. The cultivation bands are often attached to horizontal strong ropes or wires, which in turn are kept floating with buoys and stretched up between anchors. In algae culturing, algae can be grown directly on the horizontal wire. K 20120010440 shows a system of growing algae on ropes running in slings immersed in water. KR101024217 shows a system where wire rows are used to grow algae only, as well as an enclosing wire system to extend the inner wire ropes.

The design in US5438958 has a star-like shape to immerse large cultivation tanks for fish farming around a central hub. Mussel growers in Spain and Portugal use platforms from which they grow mussels hanging in ropes or strips vertically directly below the platform without spreading

horizontally.

In the salmon farming industry, it is a major problem that the cultivated fish are affected by parasites which reduce the quality of fish meat and in activities that breed other fish species in the sea, other parasites and pathogens occur, which cause impaired fish health and economic damage. Patent WO 2011101367 discloses a method of inhibiting salmon lice parasites to settle on farmed salmon.

SUMMARY OF THE INVENTION

A first object of the present invention is to be able to improve the yield from aquaculture systems. It is further an object of the invention to be able to control the amount of nitrogenous substances generated in the culture and which is emitted from the culture to the surrounding water.

In order to achieve this first object and other objects, according to one aspect of the invention, there is provided a device and embodiments thereof which enable the cultivation of a first and a second organism in water. The device comprises a platform and one or more support lines extending outwardly from the platform where each carrying line constitutes a closed loop for growing organisms at an upper depth or at a lower depth. An upper carrying line is provided for attachment of a first organism of the type of macroalgae and a lower carrying line located below the upper carrying line onto which is attached one or more cultivation bands where each of the cultivation bands is intended for cultivation of a second organism of the type filtering invertebrates. Carrying lines and cultivation bands are so arranged that they can be harvested and replanted from the platform and excretion products containing nitrogenous substances from the filtering invertebrates can be used by the macroalgae for faster growth of the macroalgae.

In order to achieve this first object and other objects, according to one aspect of the invention, there is provided a system comprising the device and embodiments thereof which enable the cultivation of a first and a second organism in water, wherein the amount of nitrogen leaving the system to ambient water is regulated by to change the biomass of the first organism and the other organism, as well as the amount of fish if the cultivation involves the cultivation of fish.

SHORT DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram showing a side view of a portion of the aqua culture device;

Figure 2 is a block diagram showing a side view of a cultivation arm of the device;

Figure 3 is a block diagram from above showing an embodiment of the device for cultivation in water;

Figure 4 is a block diagram showing a side view of another embodiment of the device for cultivation in water.

DETAILED DESCRIPTION OF THE INVENTION

The costs of cultivating Ciona must be reduced and the number of harvest days must increase in order to deliver products without interruption. The accessibility to harvest on windy days when harvesting by boat cannot be carried out must increase.

There is always a risk of crop loss if you only grow one species in a crop, as biological systems always have a built-in risk of diseases or adverse weather, which must be minimized. Growing in water means a much more even and safer climate than land-based cultivation and water-based crop systems for filter-feeding invertebrates, and algae have a significantly longer period of the year when growth occurs than in comparable systems on land at the same latitudes. This is because filtering invertebrate animals also eat heterotrophic planktonic microorganisms and algae uses the dark and cold months of the year to store nitrogen nutrients.

The ocean's ecosystem is damaged by excessive nitrogen levels and new production systems for food and products must be circular in terms of energy and nitrogen, the nitrogen we take up from the sea via products comes after being used back to sea, and shall not increase the net content nitrogen in the sea. The production must be sustainable.

Figure 1 shows a side view of culture device 100 according to the invention. The cultivation device 100 comprises four cultivation arms 1 attached to each outer end by anchors 25 and in their inner part against a floating central platform 3 on which work barges 4 are located.

Cultivation arm 1 is defined as a device consisting of carrying lines and its floating arrangements and anchors 12-25 and is intended to be performed in multiples starting from the central platform 3.

A cutting perspective of a representative portion of the culture showing water surface 80 and bottom 90 where a platform 3 is centrally located which can be held floating with pontoons 5 and loaded with work huts 4 and staff barges 6 where four species can be co-cultivated in the form of macroalgae 7 growing on an upper mostly horizontal carrying lines 12 one or more species filter- filtering invertebrates 8 growing on mostly vertical cultivation bands, in turn, hanging from a lower mostly horizontal carrying line 13, deposition eating animals 9 stored in cages or closed mesh structures. The carrying lines 12 and 13 are formed as loops and run in the peripheral part against a pulley mounted on a force distributing device 14 which are held up by tubular floats 15, 16 and in the central part are held up with angular iron mounted at the platform 17. The upper carrying line 12 is held floating using floating buoys 18 and the two carrying lines 12, 13 are stretched in their longitudinal direction with a submerged beam 24 in combination with anchors 25 and the carrying lines 12, 13 are stretched in their lengthwise direction with the tubular float beams 15, 16 and the submersed beam 24. The lower carrying line 13 is provided with smaller floating buoys to counteract the weight of the line. The carrying lines can be lifted up to a mechanical winch 19 on the platform, which facilitates the work.

Figure 2 shows a side view of a cultivation arm 1 and its attachment to the pontoons 3 in which the nitrogen removal 2 is also located. Upper carrying lines 12 and lower carrying lines 13 are held in their centrally located end by put on top of L-shaped iron mounted on platform 17 located at the two depths where macroalgae and filterers are meant to have their upper cultivation depth and in their peripheral part, closest to the anchorage, on a running pulley 20 which also allows the carrying line to be rotated in its loop. The pulley 20 is attached to a power distributor made of metal 14 to distribute the mostly horizontally pulling forces into two linear force vectors; the first directed to the tubular floating buoy 15, 16 via a rope 23 attached to the circular loop 22 of the power distributor, and the other force vector is directed down to the anchoring system via a rope attached to the bottom beam 24 which in turn is attached to the anchor 25 by means of a metal chain. The power distributor have a smaller floating buoy 21 permanently mounted to compensate for the weight of the unit.

The invention relates to a device for cultivating and harvesting aquatic animals and algae together in a device which in its center consists of a centrally placed working pontoons from which loop-shaped support lines are attached at two depths fastened at their distal end of anchors and tubular floats. In the upper layer, algae that require light are grown and in the lower layer, filtering animals are grown such as ascidians or bivalves. Nitrogen containing nutrients released by the filtering animals act as fertilizers for the nearby algae to maximize algal growth rate. Under the cultivation bands bottom living animals, living on organic depositions from the culture above, are cultivated. The invention includes technical solutions for quick and easy working with the device and achieving desired crop and harvest efficiency as well as obtaining many harvest days per year. The invention also includes a biological nitrification-denitrification inside the pontoons which allows a closed fish farming system under the hub of the culturing device where the fish are fed with fodder produced from the filtering animals.

According to a further embodiment, the cultivation device may further comprise equipment 9 for culturing deposition eating animals 9. The equipment 9 is placed on the bottom below the cultivation device. The equipment includes cages or other closed mesh structures for the cultivation of deposition eating animals.

In a preferred form, the invertebrates cultured on the ropes are colony-forming species of the genus Ciona which is a colony-forming solitary ascidian which grows very well in many sea-water areas. Hereafter, the name Ciona is used for simplicity, but the term should be interpreted to include other sessile filter-feeding invertebrates.

By co-cultivation of Ciona with other marine species such as algae, fish and various invertebrates, a solution to the above mentioned problems is obtained. In co-cultivation, the different cultivated species share a common cultivation unit on the same cultivation area, as well as share boat and personnel resources for cultivation and harvesting as well as transport to land. Co-cultivation also shares the costs of exploitation in the form of environmental studies and environmental permits.

Co-cultivation gives you several technical / biological benefits. Ciona, an invertebrate animal, excretes nitrogen substances, mainly as ammonium, which acts as a potent fertilizer for the macroalgae grown on the same surface closest to the surface. Macroalgae grown closest to the surface shade the Ciona bands underneath. This means that the Ciona are not overgrown with microalgae or macroalgae, which is an advantage when Ciona is to be harvested and its outer body part, the tunic, is to be used for cellulose products. Even the faeces that Ciona release in large quantities are good food for several aquatic invertebrates. Such animals are by persons skilled in the art termed deposit feeders, which means that they eat carbon rich particles that fall to the bottom. When co-cultured with deposit feeding aquatic animals, one can increase the growth rate of such animals and keep them inside suitable devices such as cages or nets. An example of such animals are different species of sea cucumbers which pay a high price as delicacy in Asia. Even crayfish and crustaceans of various kinds are suitable species to cultivate. Some species of marine polychaete worms are also suitable species to cultivate.

Figure 3 shows the cultivation device from above. The carrying lines are arranged in opposing groups called cultivation arms 1, in the figure encircled by a dotted circle located around the platform 3 which then forms a central hub of the device and in which each group of carrying lines in its outer position is anchored in the bottom which allows that the central platform does not need to be anchored.

Figure 4 shows an embodiment in which cultivation of sessile invertebrate filter-feeders is combined with macroalgae cultivation and fish farming and thus can produce the fish feed locally. The cultivation device 100 comprises four cultivation arms 1 attached at the distal end by anchors 25 and in their inner, proximal, part against a floating central platform, also termed pontoon, 3 on which work huts or containers 4 are located. A cross-section of a representative portion of the culture showing water surface 80 and sea bottom 90 where a platform 3 is centrally located which can be held floating with pontoons 5 and loaded with work huts or containers 4 and personnel huts 6 where four species can be co-cultivated in the form of macroalgae 7 growing on the upper mostly horizontal carrying lines 12, one or more species sessile filter feeding invertebrates 8 growing on mostly vertical cultivation bands, in their turn hanging from the lower mostly horizontal carrying line 13, deposition eating animals 9 stored in cages and a fish species enclosed in an open or closed structure 11. The carrying lines 12 and 13 are designed as loops and run in the peripheral part against a pulley mounted on force distributors 14 which are held up by tubular floats 15, 16 and is hold up in the central part with L-shaped iron mounted in the platform 17. The upper carrying line 12 is held floating by floating buoys 18 and the two support lines 12, 13 is extended in its longitudinal direction, perpendicular to its lengthwise direction, by a submerged beam 24 in combination with anchor 25 and the carrying lines 12, 13 are stretched in their transverse direction with the tubular floating beams 15, 16 and the submerged beam 24. The lower support line 13 is mounted with smaller floating buoys to counteract the weight of itself.

When the cultivation contains fish farming, cultivation and harvesting of macroalgae and Ciona functions as a compensatory nitrogen absorption for the entire system. This makes the fish farming in its immediate vicinity compensated for nitrogen emissions, which reduces negative effects on the aquatic environment. A nitrogen budget can be set up to calculate a net flow of nitrogen from the cultivation system, where the budget parameters are determined by the annual crop weight of cultured species, the nitrogen content of the species and the calculated nitrogen losses of the fish feed from the feed additive. With knowledge of the nitrogen uptake in cultivated species, nitrogen concentrations at harvest and growth rates, it is possible to design a system of different biomasses of cultivated species, so that the cultivation system either gives a net uptake of nitrogen from the sea, is nitrogen neutral or is a net release to the sea. The fish farm is designed as a closed system where no water leaks from the culture vessel to the surrounding water and the water in the vessel is pumped into the nitrogen removal part 2 located in the inner parts of the platform's pontoons where nitrogen removal from the water in the form of nitrification and denitrification is ongoing using aerobic and anaerobic bacteria. If necessary, new water can be added to the closed vessel to compensate for evaporation, leakage or the need for a certain exchange of water. In embodiment according to this invention, new water is taken from the center of the whole culture device, which means that water supplied to the fish farm has low concentrations of unwanted parasites and pathogens as these are filtered off by the surrounding filtering invertebrates. The working platform in the central part of the culture allows such fish farming as the floor of the platform central part can be opened and the farmed fish can easily be deployed, handled and harvested. Ciona, and or other suitable invertebrate filtering animals harvested in the cultivation system are meant to be converted into fish feed, and can then be used as feed for the fish in the crop without or after a feed processing. Some fish can eat Ciona bodies without preparation, which is a cost-reduction method.

By constructing the crop in a star form, you get several advantages. New fresh, particle- and nutritional rich water is easier to enter the culture, which is very important for the growth rate of sessile filtering invertebrates. The area that is used for culture is, in our special case and only given as an example of the scale of the cultivation, 1 hectare if we calculate each arm strictly based on a flat projection on a map. If we count on the entire effective area that the culture are taking water from, it will amount to 16 hectares. A centrally positioned hub consisting of concrete or metal pontoons serves as a work platform where both harvesting, maintenance and deploys new crops are continuously ongoing. The work platform allows work in stronger wind forces than currently used boat-based harvesting systems used for mussel cultivation. On the platform, containers can be placed where harvesting equipment, engines and energy production systems are protected from weather and wind. Containers can also be used to accommodate equipment for treatment of harvested biomass such as dewatering, separation into various desired fractions, hygienisation, drying and packaging. The work platform allows a better and safer working environment and a shed for personnel can be placed on top of the container modules. Who does not want to sit inside the heat when there are minus degrees and gale outside?

The loop allows both harvest and release of new bands throughout the year, which is preferable for the cultivation of ascidians of the species Ciona intestinalis, Ciona savignyi and Ciona robusta as these have several breeding periods per year depending on average water temperature.

The platform that constitutes the hub consists in one embodiment of a concrete pontoon and has a number of right angled bars located on the submerged edges at two depths allowing the cultivation bands, both for macroalgae and Ciona, to be formed as loops that can be pulled continuously for harvesting while the harvested band again goes away from the platform and can be replanted by new macroalgae and Ciona. The loop runs at the other end in a pulley which, in turn, is hold up on a mechanical arm in conjunction with a floating buoy and stretched up by a common anchor for all carrying lines in the cultivation arm. The mechanical arm is designed so that the various actuating forces are converted to linear tensile forces and torque is avoided. The loop can be lifted onto the platform up to a mechanical winch 19 which facilitates the work. A specially designed hook is used to capture the loop of horizontal bands and drag it over the winch which is open on one side, allowing the loop to be applied and removed from the winch without opening.

In one embodiment the platform consists of concrete pontoons, these can also act as a holding tank for nitrogen removal from the water phase by microbes performing nitrogen removal through nitrification and denitrification in the same way as in a sewage treatment plant and where the environment in the concrete pontoons can be divided to separate the process into aerobic and anaerobic stages, and a previous sedimentation step and flocculation step. When such a system is used, it is possible to have a closed fish farm under the platform whose water is continuously purified inside the pontoons from nitrogen and organic matter. Before the water is returned to the fish farming vessel, the water is oxygenated in a conventional manner. An aspect of the invention is that the risk of pathogens and parasites on the fish is reduced when new water is taken into the system from the water filtered by the invertebrate filtering animals.

Fish farming in open water is well known. The culture can be located in net pens where water flows in and out of the cultivation relatively freely, which is the most common method. Cultivation can also occur in more or less sealed tanks at sea where the water exchange to surrounding waters is regulated from completely closed to relatively open. In many waters, the levels of excessive substances such as nitrogen and phosphorus are too high in the water, leading to undesired effects which lead to strict regulations on fish farming and how much nitrogen they may release into surrounding waters. Fish farms in open net boxes emit much more nitrogenous substances to surrounding waters than closed systems, but closed systems must clean their culture water from nitrogenous substances to achieve adequate water quality for fish farming. As it is shown in the patent publication US2015079223 that the Ciona inner body can be used as fish feed, we get a feed production system without transport costs where the filtering Ciona animals continuously produce feed through growth and harvest, which is directly separated into a feed fraction given to the fish in the star culture. This may seem a mindset of circularity and public resource management - however this is also very good from a commercial perspective; partly to minimize the transport costs for the feed and that you as a star-culturist make and process the feed fraction instead of buying it from elsewhere. The locally produced feed should be seen as a supplement, or in some cases as an alternative, to commercially available feed.

Using a centrally positioned hub as a work platform, from which horizontal lines and vertical bands are arranged which can be harvested and replanted from the platform and that these lines are anchored at their distal end, results in the platform not having to be anchored. Another advantage is that the use of boats for harvesting the biomass is avoided and it is sufficient with commonly available, and therefore cheaper, ships. An additional advantage is that a cultivation design is achieved which maximizes the water exchange for the filtering animals, which results in a higher growth rate.

Furthermore, it is a new aspect to cultivate both sessile filtering invertebrates and algae on bands suspended in horizontal lines designed as loops or closed loops. The loop or closed loop allows both harvest and release of new bands throughout the year, which is preferred for growing ascidians of the genus Ciona as these have two breeding periods per year.

The number of harvest days in today's aquaculture system is limited to days when the wind is not too strong for harvest or boat transport to and from the harvest area. Based on our own measurements when cultivating and harvesting Ciona, the proportion of days when harvesting cannot be carried out has been 40 % of all working days, which were the occasions when the wind either exceeded 7 meter per second, came from the wrong wind direction or that the wave height was too high.

The circularity system of the culturing device is arranged so that the amount of nitrogen leaving the system to the surrounding water can be regulated by changing the biomasses of the first organism of the type of macroalgae, the other organism of the type of filter feeding aquatic animal, and if the system comprises a fish farming, the amount of fish in the culture.