Field of the invention

The present invention relates to a feeding system and a method for operating said feeding system for feeding marine organisms within an aquaculture pen in a fish farm. The system comprises a floating feed spreader connected to a feed station by a tubular. The feed spreader having an outlet for feed.

Background of the invention

The aquaculture industry has developed into a billion-dollar business worldwide. The industry aims to produce safe, healthy and good seafood, in addition to create jobs. Over the past few years, the industry has faced stricter governmental regulations, especially concerning sustainable production. Sustainable farming that keep the environmental footprint within acceptable limits is a prerequisite for long-term growth of the industry. One of the many aspects in a sustainable production line is an efficient method of feeding the fish.

A fish farm typically consists of several different aquaculture pens connected together, containing fish at different stages in their life cycle. The size of an aquaculture pen usually ranges from 30-50 meters in diameter and 30-50 meters in depth. Normally a common feed station will provide the different aquaculture pens with feed from a silo through a feed spreader. The feed spreader is usually fixed at the centre of the aquaculture pen by ropes or wires attached to the outer ring of the aquaculture pen, typically with three ropes. The feed spreader is connected to the silo in one end, and the other end has an outlet for the feed. In some configurations, feed is ejected from the outlet in a circle around the feed spreader, as the outlet rotates about its own axis. In a common embodiment, the outlet is protruding above the water surface in a somewhat horizontal direction, or the outlet can have an angle relative to the water surface. Usually one or more buoys are used to keep the feed spreader floating in the water surface. It is also known an embodiment were the feed spreader is submerged under water. In that case, the feed is mixed with water in the tubular from the silo, so that a mixture of feed and water are spread out into the aquaculture pen.

A problem related to feed spreaders fixed inside the aquaculture pen with ropes or wires attached to the aquaculture pen ring is that the ring changes shape due to wind and current. The aquaculture pen ring can become oval when current and wind is acting on the ring, resulting in slack rope or wires, thus the feed spreader is allowed to move from the centre of the aquaculture pen. The feed spreader will then move with the current and/or wind. Moving in the direction of the current will result in that more feed is brought out through the side of the aquaculture pen before it is eaten by fish.

Ovality due to current can in extreme situation led to tearing of the ropes that fixes the feed spreaders since they are not strong enough to withstand the enormous forces in when the current affects the ring.

How efficient the feeding process is depending on different factors. Specific locational features of the sea or the fjords, seasonal changes, weather parameters such as light condition, temperatures in the water, wind direction, wind power, water current and water direction etc. is examples of such factors. For instance, when the temperature in the top layer of the water is warm, the fish tend to retreat to deeper water, typically minus 15m meters from the water surface. This situation is demanding for the feeding process when the feeding is done above the water surface. Large portions of feed provided into the aquaculture pen will exit the sides of the cage before it reaches the fish. This is especially dependent on other additional weather parameters such as water current. In some cages, the feed sinks straight through the sides or to the bottom of the aquaculture pens and creates waste in the ocean, in addition to contribute to excess food production and waste. For closed aquaculture pens, the feed that sinks to the bottom together with other waste produces a toxic environment for the fish. This is a huge problem for the fish farmers. A common feed used for farmed fish today is pellets. They vary in size, weight and nutrition content. This will determine their sinking properties in the water in addition to wind power, wind direction, water current and water direction, the pressure in the tubular, diameter of the outlet etc. Exposed to rough conditions, such as high pressure in the tubular, will break the pellets. This can damage the feed spreader and lead to insufficient feeding of the fish. The amount of feed that will be eaten by the fish is dependent on the combination of these properties among others. A measurement tool used to determine how much feed is needed for a fish to gain 1 kg of weight is called the feed factor. It is an object for the farmer to keep the feed factor as low as possible.

Today, significant portions of the feed sink straight through the aquaculture pen or is collected at the bottom of closed cages without being caught by the fish.

Consequently, farmers need to add more feed to the fish farm then necessary to get the fish to grow sufficiently. The farmers aim to provide enough feed for the breeding fish while at the same time keeping the level of feed low to keep production costs and the environmental damage to a minimum. Thus, there is a need for a new system and method of how to distribute the feed in a more efficient way to reduce the feed factor of the fish farms.

Objects of the present invention

The invention has one or more of the following objects:

- provide a system for adjusting the position of a feed spreader

- provide a method for adjusting a feed spreader

- provide a system where a feed spreaders position is adjustable in the aquaculture pen above the water surface, or in the water surface or submerged in the water

- provide a system that can calculate a preferred position for a feed spreader within an aquaculture pen based on measured weather parameters and other parameters, and position the feed spreader accordingly

-provide a method for calculating the preferred position for a feed spreader within an aquaculture pen based on weather parameters and other parameters, and position the feed spreader accordingly - provide a feeding system where the position of the feed spreader is manually adjustable

- provide a feeding system where the position of the feed spreader is adjusted by one or more motors

- provide a system that can detect ovality in an aquaculture pen ring

- provide a method to detect ovality in the outer ring of an aquaculture pen ring

- provide a system for detecting ovality in the outer ring of an aquaculture pen and adjust the fastening means of the feed spreader accordingly

- provide a system and/or a method for detecting direction and/or strength of the current, based on measurements of the stretch of the ropes or lines fixing a feed spreader inside the aquaculture pen

- provide a system and/or a method for avoiding slack in ropes or lines that fixes a feed spreader inside an aquaculture pen

- provide a system and/or method where sonar is used to detect aquaculture pen ovality

- provide a system and/or method where sonar is used to detect where the majority of fish is positioned inside the pen and optimise the feeding based on the position of fish

Summary of the invention

The invention is in one aspect related to a feeding system for feeding marine organisms within an aquaculture pen in a fish farm. The feeding system comprises a floating feed spreader connected to a feed station by a tubular and the feed spreader having an outlet for the feed. The feed spreader is connected to an aquaculture pen ring with at least one adjustable fastening means.

The one or more fastening means can comprise a rope connected to a winch at the aquaculture pen ring and to the feed spreader at the other end.

The one or more fastening means can comprise a rope connected to a winch at the feed spreader and to the aquaculture pen ring at the other end. One or more of the adjustable fastening means can comprise a pulley or a block positioned under water. This can be for submerging the feed spreader by pulling on the rope. The rope is passing through the pulley or block and can be pulled by one of the winches.

The system can comprise one or more sensors for measuring one or more weather parameters.

The system can comprise a control unit for receiving one or more weather parameters and operating the one or more winches.

The system can comprise sensors for monitoring tension in the adjustable fastening means, for detecting ovality in the aquaculture pen ring.

In another aspect the invention relates to a method for operating a feeding system for feeding marine organisms within an aquaculture pen in a fish farm. The method comprises the steps of:

-providing a feeding system comprising:

- a floating feed spreader connected to a feed station by a tubular and the feed spreader having an outlet for the feed,

- one or more adjustable fastening means, for fixing the feed spreader and moving the feed spreader within the aquaculture pen, and

- sensors for monitoring the condition of the system and the surroundings,

- measuring parameters relates to the feeding system and its surroundings

- calculating a preferred position for the feed spreader within the aquaculture pen based on the parameters measured by the sensors, and

- moving the feed spreader to the preferred position by adjusting the adjustable fastening means.

The one or more fastening means can comprise a rope connected to a winch at an aquaculture pen ring and to the feed spreader at the other end. The one or more fastening means can comprise a rope connected to a winch at the feed spreader and to an aquaculture pen ring at the other end.

One or more of the fastening means can comprise a pulley or a block positioned under water, for positioning the feed spreader under water, by pulling on the rope, passing through the pulley or block, with one of the winches.

The sensors can measure parameters selected from a list of: wind power, wind direction, water current, water current direction, water temperature and light conditions.

The system can be automatically driven by a control unit that calculates a preferred position and operates one or more motor driven winches to pull or release the ropes to move the feed spreader to said preferred position.

The method can comprise the steps of measuring tension in the one or more ropes for detecting ovality in the aquaculture pen ring and adjusting the tension in the ropes based on the measurement.

The method can comprise the step of using sonar to detect ovality in the aquaculture pen ring and adjusting the tension in the ropes based on the measurement.

The method can comprise the step of providing a sonar as part of the system, the sonar is to be used to detect the position of the majority of fish inside the aquaculture pen, the position of the majority of fish can be used as a parameter for calculating the preferred position of the feed spreader.

Description of the diagrams

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:

Figure 1 shows an overview of the fish farm with different aquaculture pens connected to a common feed station. Figure 2 shows an embodiment of the invention where a feed spreader is located within an aquaculture pen, attached to winch rope configuration with winches on the cage ring.

Figure 3 shows another embodiment of the invention where the feed spreader is located within an aquaculture pen, attached to winch rope configuration with winches positioned on the feed spreader.

Description of preferred embodiments of the invention

Reference is made to figure 1 , which shows an overview of the fish farm 10. In this embodiment, the fish farm 10 comprises six aquaculture pens 1. In the middle of each aquaculture pen 1 there is positioned a floating feed spreader 4. In this configuration, the feed spreader 4 is kept within the aquaculture pen by three ropes 5 connected to a winch 2. The invention is not limited to three winch ropes, other configurations such as four or five ropes can also be used.

The winch 2 is connected to the aquaculture pen ring 3 and the rope is connected to the feed spreader 4. The feed spreader is kept floating in the water surface by means of doing so, such as buoys or ropes (not shown). Alternatively, the feed spreader can be kept above the water surface by means of doing so, such as suspending the feed spreader in air by tight ropes.

The feed spreader may also be submerged under water. In such a configuration there may be one or more ropes 5 under water connected to the feed spreader 4 for moving its position lengthwise and depth wise. This can be in addition to other winch rope configurations. The winches 2 can for instance be connected to the feed spreader 4 or to a position under water, such as at the bottom of the net cage, or at another suitable position under water. To avoid submerging one or more winches, blocks or pulleys can be placed below water. The rope or line for adjusting the depth of the feed spreader can then be stretch from the feed spreader to the winch above water via one or more pulleys or blocks below water.

The depth of the feed spreader can for instance be at a preferred depth for the fish at a certain location in the fjords or the sea, or at a level that is beneficial for the fish for instance at certain water temperatures. In this embodiment, feed is mixed with water in the tubular 6 from the feed station 9.

When the feed spreader is above or at the water surface, the feed is blown out from the feed station 9 together with air. The feed spreader 4 has an outlet for the feed. In one embodiment this is arranged for rotation about its own axis to spread the feed in a circle around itself. The outlet may be shaped like a nozzle, cone, funnel or ring. The outlet can point in a direction parallel to the water surface or at an angle upwards or downwards. In a common embodiment the outlet is protruding at a height above the water surface, but the invention is not limited to this. The feed spreader 4 is connected to a common feed station 9 by a tubular 6. In this context a tubular is a tube-shaped body, a duct, a pipe, pipeline, or a hollow body for transportation of feed. The tubular can be either flexible, firm or semi-flexible. In the embodiment shown in figure 1 , six separate tubulars 6 are running out from the feed station 9 and branch off to six separate aquaculture pens 1. Other embodiments of this

configuration are also possible, with one or more common tubulars 6 from the feed station 9 that branched off to more than one aquaculture pen 1 , etc. The feed station 9 may contain one or more silos (not shown) with feed of different properties for the fish at different stages in their life cycle. The feeding system further comprises blows for blowing the feed from the feed station and out through the outlet of the feed spreader (not shown). By stopping the blowers, the feeding is stopped or started for each aquaculture pen. In this system, valves may be used for shutting out one or more aquaculture pens from the feeding process. This is usually operated at the feed station 9 or by stopping/starting the blower.

An aquaculture pen in this invention defined as an open water-permeable aquaculture pen, or semi-open water permeable aquaculture pen, or closed water- impermeable aquaculture pen, or a steel tank or a rearing tank, or another suitable body for farming marine organisms. The feed used in this system comprises pellets and other types of feed used for feeding marine organisms.

An alternative configuration is shown in figure 3, where the winches 2 are connected to the feed spreader 4 and to the rope 5 is connected to the aquaculture pen ring 3.

The winches 2 is operated by motors in a preferred embodiment. Otherwise, the winches 2 are manually driven. According to the invention, a rope 5 may be a fibre rope, a wire, a chain or the like.

In a preferred embodiment, the system further comprises one or more sensors for measuring different weather parameters such as wind power, wind direction, water current, water direction, water temperature, light emission and so on. The sensors are positioned in the fish farm 10, at the feed station 9 or at another convenient location above or under water. The system further comprises a control unit that receives weather parameters and possibly other parameters from the one or more sensors and with a computer program calculates a preferred position for the feed spreader 4 according to this data. In an automated embodiment of the invention, the control unit operates the winches 2, so that the feed spreader 4 is moved

automatically to the preferred position by the motors. Access to the preferred position will be limited by the number of rope winch configurations. If a feeding system have three such configurations, the ropes 5 connected to the feed spreader 4 can be pulled or released in any combination between the three connection points in the aquaculture pen 3. If for instance, the system only has one rope winch it will limit the possible preferred positions for the feed spreader 4 to be along a line. The system will calculate a preferred position according to the possible options by the rope winch configurations. If there are for instance several rope winches there will be a lot more combinations possible for pulling or releasing the different ropes 5 by the different winches 2 to position the feed spreader 4 to the preferred position.

To avoid the problems relates to ovality of the aquaculture pen ring 3, sensors monitoring tension in the ropes 5 can be included in the system. If increased tension in one rope 5 is detected the winch 2 can gradually release rope 5, or if decreased tension is detected the winch 2 can pull in rope 5 to compensate. The sensors detecting tension can also be used as input to calculate the direction and strength of the current, which again can be used to positioning the feed spreader 4 to optimise the feeding to avoid feed drifting out of the aquaculture pen 1 before eaten by fish.

As an alternative to or in addition to, sensors detecting tension, sonar can be used to detect ovality this can be done by detecting the distance between two points on the ring 3 (the diameter of the ring for instance) across the aquaculture pen 1. Preferably the diameter is detected several places around the aquaculture ring 3.

Another feature that can be implemented in the feeding system 4 is sonars for detecting the position of the majority of fish in the aquaculture pen 1. If the position of the fish is known it can be used as an additional parameter for positioning the feed spreader so as much feed as possible is eaten by the fish.

When the system is manually operated, the fish farmer moves the feed spreader 4 to the desired position, by adjusting the ropes 5 by pulling or realising the winch 2. Based on know-how of how the feed will drift in the water at different weather conditions, the fish farmer will move the feed spreader 4 to the preferred position.

The weather condition may be evaluated by the weather parameters from the sensors, or from other weather stations or weather forecasting means. Manual operation may also be necessary during maintenance and service of the aquaculture pen or the system, or in other situations where the feed spreader needs to be manually operated.

The automatic operation of the feed system may be controlled from the feed station or at another location in the fish farm 10. In a preferred embodiment according to the invention, the feeding system is operated automatically at a distant location such as at a growth centre onshore. This enables the fish farmer to control the feeding process from different locations. In yet another embodiment, the control system can be operated from any location with internet connection. In an automatic operation mode, the system can move the feed spreader 4 continually or in predetermined time intervals. The system can also be configured so that the position of the feed spreader 4 is changed only when changes in a weather parameter exceed a set limit.

To illustrated how the invention works: If the wind direction and the water current is coming from the north, the feed spreader 4 will be directed from the centre of the aquaculture pen 1 to a position further north inside the aquaculture pen 1. This will extend the floating time of the feed within the aquaculture pen 1. The computer program in the control unit may adjust for the pressure in the tubular 6, the angle of the outlet, the weather parameters and other relevant parameters concerning the particular location for the fish farm. By moving the feed spreader 4 to the preferred position also ensures that the north end of the cage is covered within the feed-range of the feed spreader. Compared to current technology where the feed spreader is fixed at the centre of the aquaculture pen, a larger portion of the feed is kept floating for a longer time within the aquaculture pen. Thus, covering a larger area within the aquaculture pen 1 with feed.

Three adjustable fastening means as showed in figure 1-3 is preferred, but four and five or even a higher number of adjustable fastening means can work. Less than three adjustable fastening means can also work. Each adjustable fastening means preferably comprises an electrical motor driven winch, and a rope connected to the winch in one end and to the feed spreader in the other end, in such an embodiment it is preferred to have at least two adjustable fastening means.

In another possible embodiment, the adjustable fastening mean comprises a rope 5, and a power block instead of a winch 2 or a winch 2 used as a power block, where the rope is connected to the feed spreader in both ends, and passes through a pulley or block on one side of the aquaculture pen ring, and through the power block on the other side of the aquaculture pen ring 3. Such a solution might require a different adjustment method for adjusting for aquaculture pen ring 3 ovality, as the distance between the power block and the pully or block on the other side might change. A flexible and/or biasing member such as a spring connecting the pulley or block to the aquacultural pen ring can then be used.

In one embodiment one or more fastening means are positioned under water for submerging the feed spreader 4.

The invention also relates to a method for operating a feeding system for feeding marine organisms within an aquaculture pen 1 in a fish farm 10 comprising a floating feed spreader 4 connected to a feed station 9 by a tubular 6 and the feed spreader 4 having an outlet for the feed, wherein the spreader 4 is moved to a preferred position by adjusting at least one adjustable fastening means, and where the preferred position is calculated from at least one weather parameter. Weather parameters can be obtained from measurements from one or more sensors or from weather stations, or a combination of both.

The system can be automatically driven by a control unit that calculates a preferred position and operates the one or more motor driven winches 2 to pull or release the ropes 5 to move the feed spreader 4 to said position.

The preferred position or optimal position can be recalculated and the feed spreader 4 can be moved accordingly, at fixed time intervals. The preferred position can be recalculated and the feed spreader 4 is moved accordingly, when a weather parameter changes above a set level.

The control unit can use machine learning to predetermine the preferred position for the feed spreader 4 and move the feed spreader 4 accordingly.