GB1590781A

GB1590781A - Fish rearing apparatus

Info

Publication number: GB1590781A
Application number: GB39644/77A
Authority: GB
Original assignee: Fisons Ltd
Current assignee: Fisons Ltd
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-06-10

Description

(54) FISH REARING APPARATUS (71) We, FISONS LIMITED, a British Company, of Fison House, 9 Grosvenor Street, London W1X OAH, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a device for use in the rearing of fish.

In rearing fish it is often necessary to hold them in tanks through which fresh water is circulating. This is conventionally done in land based tanks or in a series of interconnecting basins in a stream. However, both forms of construction are comparatively expensive to construct and operate.

Furthermore, once installed they are fixed and the design of the installation cannot be readily altered.

The present invention relates to a novel form of holding tank assembly which comprises a series of pens adapted to contain fish and to permit the flow of water therethrough and linked to both sides of an elongated walkway provided with buoyancy means whereby the whole assembly can float in water, e.g. in a lake or river, with the walkway leading from land to the assembly.

Surprisingly we have found that the loss of food from pens during the fresh water stage of life of anadromous fish (notably of atlantic salmon) is comparatively small and that this can be accepted commercially.

The assembly of the invention offers a flexible form of construction which can be altered or enlarged with ease merely by moving or adding pens onto the walkway. Yet it overcomes the problems with land based holding tanks of the need to supply and circulate water.

For convenience, the invention will now be described with reference to the accompanying drawings in which Figure 1 is a plan view of a preferred form of the holding tank assembly and Figure 2 is a vertical section through one of the tanks shown in Figure 1.

The assembly comprises a floating pontoon or walkway 1 moored at one end to the land and extending out into a body of water, e.g. a river or lake. The walkway 1 can be formed by hollow box-like units linked together in a flexible manner or by pairs of drum-like members 2 supporting a suitable cat-walk 3 as shown in Figure 2.

The walkway 1 is provided to each side thereof with pens 4 in which the fish are reared. The pens are constructed so as to permit water to flow through the tank, thus renewing the water in the pen and providing the necessary oxygenated water for the fish. It is therefore preferred to construct the pens from a reticulated material with a suitably sized mesh, notably a plastics coated or galvanised metal mesh grid. Typically, the pens are of generally rectangular shape. Conveniently the side walls and base are all constructed of meshed or apertured material preferably supported on a suitable framework 5.

The pens 4 are attached to the walkway 1 to permit feeding and collection of the fish. It is preferred that each pen 4 be so mounted that it can be partially or wholly raised out of the water to facilitate servicing.

For example, each pen is mounted on the walk way by pivot means, e.g. is hinged to the walkway 1, so that the pen can be pivotted about a generally horizontal axis to tilt the pen towards the walkway. Lifting gear 6 (e.g. a davit-type lifting gear) is provided on the walkway to lift the outer edge of the pen as shown on the right hand side of Figure 2. This, has the effect of concentrating the fish in a smaller volume of water closer to the walkway.

The pens 4 and walkway 1 may also be provided with means for feeding the fish and with other necessary equipment, e.g.

lighting.

The configuration of the walkway can be readily altered by the addition of further lengths of walkway in any suitable direction, and the capacity of the assembly may be increased by the addition of further pens.

The invention also provides a method for rearing fish in fresh water, notably ana dromous fish in their fresh water stage, in which the fish are contained in a pen of an assembly of the invention and fresh water is allowed to flow spontaneously, that is without the assistance of pump means, through the pens. The anadromous fish are preferably of the salmon family and are reared in the pens up to the parr stage.

WHAT WE CLAIM IS: 1. An assembly which comprises a series of pens adapted to contain fish and to permit the flow of water therethrough and linked to both sides of an elongated walkway provided with buoyancy means whereby the whole assembly can float in water.

2. An assembly as claimed in claim 1 wherein the bouyancy means are provided by forming the walkway from hollow units or by providing the walkway with hollow units attached there to.

3. An assembly as claimed in either of claims 1 or 2 wherein the pens are formed from a reticulated material.

4. An assembly as claimed in any one of the preceding claims wherein the pens are mounted on the walkway so that they can be partially or wholly raised from the water on which the walkway is to float.

5. An assembly as claimed in claim 4 wherein the pens are mounted upon the walkway by pivot means whereby the pens can be pivotted about a horizontal axis.

6. An assembly as claimed in claim 5 wherein the pens are mounted on the walkway by means of hinges.

7. An assembly substantially as hereinbefore described.

8. An assembly substantially as hereinbefore described with respect to and as shown in the accompanying drawings.

9. An assembly as claimed in any one of the preceding claims wherein the walkway and pens are floating in fresh water with one end of the walkway moored to land.

10. A method for rearing fish in fresh water in which the fish are contained in a series of pens having walls through which water can flow and linked to both sides of an elongated walkway floating in the water and water is allowed to flow spontaneously through the pens.

11. A method as claimed in claim 10 wherein the pens are provided by an assembly as claimed in any one of claims 1 to 9.

12. A method as claimed in claim 10 wherein the fish are anadromous fish in their fresh water stage.

13. A method as claimed in claim 12 wherein the fish are of the salmon family.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. dromous fish in their fresh water stage, in which the fish are contained in a pen of an assembly of the invention and fresh water is allowed to flow spontaneously, that is without the assistance of pump means, through the pens. The anadromous fish are preferably of the salmon family and are reared in the pens up to the parr stage. WHAT WE CLAIM IS:

1. An assembly which comprises a series of pens adapted to contain fish and to permit the flow of water therethrough and linked to both sides of an elongated walkway provided with buoyancy means whereby the whole assembly can float in water.

7. An assembly substantially as hereinbefore described.

13. A method as claimed in claim 12 wherein the fish are of the salmon family.