GB2221822A

GB2221822A - Fish protection system

Info

Publication number: GB2221822A
Application number: GB8819784A
Authority: GB
Inventors: Patrick Frederick Ferrari
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-08-19
Filing date: 1988-08-19
Publication date: 1990-02-21
Also published as: GB8819784D0

Abstract

A protection system for protecting fish in a pond (1) comprises a plurality of support rod assemblies (2) for supporting and guiding threads (4) so as to extend around the perimeter of the pond at a predetermined height above the pond surround, and at a predetermined distance from the pond perimeter. The threads (4) are attached to the support rod assemblies (2) in such a manner as to permit the threads to move laterally towards the pond perimeter through a predetermined distance without the threads breaking or the support rod assemblies deflecting. <IMAGE>

Description

FISH PROTECTION SYSTEM This invention relates to a fish protection system, and in particular to a system for preventing predatory birds (such as grey herons) from attempting to attack fish from the edge of an ornamental pond or tank.

One of the major problems of keeping fish, either by hobbyists in ornamental ponds or by fish farmers in tanks, is that grey herons try to catch the fish. A heron does this by wading into a pond, and then stabbing its prey with its beak. Even if a heron fails to 'land' a fish in this way, its beak can damage a fish, which will then lie in the pond (or tank). If, as is probable, such a damaged fish dies, it will pollute the pond, thereby requiring the trouble and expense of cleaning and/or draining. As some fish can cost up to 1,000 or more, it will be apparent that this is a serious problem.

The usual way of deterring or preventing herons attacking fish in a pond or tank is to place rods or upright netting round the edge of the pond or tank.

Unfortunately, this is not a very effective solution, and both rods and netting are unsightly, and so detract severely from the appearance of an ornamental pond. It is also known to stretch thread between rods placed round a pond or tank. The thread is an effective heron deterrent, as a heron does not like the feel of a thread against its legs, and so will retreat from the edge of a pond or tank guarded in this manner. Unfortunately, such threads tend to be blown down or snapped by contact with the legs of larger creatures (in particular humans). Moreover, firm taut threads can be dangerous, as they can trip up humans, and in particular children.

Other known heron deterrent systems, such as audio scarers and plastic decoy herons have a limited deterrent effect, as herons tend to get used to them, and so eventually ignore them.

The present invention provides a protection system for protecting fish in a pond, the fish protection system comprising a plurality of support rod assemblies for supporting and guiding thread means so as to extend around the perimeter of the pond at a predetermined height above the pond surround, and at a predetermined distance from the pond perimeter, wherein the thread means is attached to the support rod assemblies in such a manner as to permit the thread means to move laterally towards the pond perimeter through a predetermined distance without the thread means breaking or the support rod assemblies deflecting.

With this system, a heron trying to reach fish in the pond will brush against the thread means with its legs, and this will deter the heron from proceeding further.

Advantageously, the predetermined height lies within the range of from 9 to 15 inches, and preferably is substantially 12 inches. Conveniently, the predetermined distance between the thread means and the pond perimeter is between 12 and 18 inches.

In a preferred embodiment, the support rod assemblies support and guide a second thread means. The or each thread means may be constituted by a plurality of threads.

Preferably, each support rod assembly includes a support rod which can be fixed into the pond surround, and at least one support arm extending at right-angles to the support rod. Where there are two thread means, each support rod assembly includes two support arms. In one form of support rod assembly, the two support arms are co-axial, and each support arm is provided with an eyelet through which the associated thread can pass. In another form of support rod assembly, the two support arms lie at right-angles to one another, and each is provided with two eyelets through which associated threads can pass.

This second form of support rod assembly is used to support and guide threads around a right-angle corner of a pond.

In a preferred embodiment, one end of each thread is fixed to a first support rod assembly, the other end of said thread being held against a second support rod assembly by means of a weight attached to said other end.

Advantageously, each thread is a black braided terylene thread.

A fish protection system constructed in accordance with the invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a plan view of a rectangular pond protected by the fish protection system; Fig. 2 is a schematic side view of the pond and system of Fig. 1; Fig. 3 is a plan view of a support rod assembly of the system of Figs. 1 and 2; Fig. 4 is sectional side view of part of the system; Fig. 5 is side view of another form of support rod assembly of the system; and Figs. 6 to 10 are plan views showing how the system can be adapted to ponds of different shapes.

Referring to the drawings, Figs. 1 and 2 show a rectangular fish pond 1 having sides of length 12 feet and 4 feet. A respective support rod assembly 2 is positioned adjacent to each of the four corners la, ib, Ic and Id of the pond 1. Each assembly 2 has a support rod 2a having a pair of support arms 2b at its upper end.

The rod 2a has a length of 18 inches, and the arms 2b each have a length of 9 inches. The rods 2a and the arms 2b are made of stainless steel or aluminium. As shown, the arms 2b of each assembly 2 are at right-angles to one another and to the associated rod 2a. Each support arm 2b is provided with a pair of stainless steel eyelets 3 for supporting and guiding threads 4. The eyelets 3 of each arm 2b are spaced apart by a distance of 7 inches.

In use, the support rods 2a are fixed into the pond surround, for example by being cemented into holes drilled into the pond surround. The rods 2a are arranged to project upwardly from the pond surround so that their arms 2b lie about 12 inches above the pond surround. The eyelets 3 are used to support and guide pairs of parallel threads 4. The threads 4 are black braided terylene threads, and each extends between the assemblies 2 at the corners la and 1c of the pond 1. The threads 4 of one pair are fixed to the eyelets 3 of the assembly 2 at the corner 1a, and are held against the eyelets 3 of the assembly 2 at the corner 1c by 4 ounce weights 5, these threads having passed through the eyelets 3 of the assembly 2 at the corner 1b.The weights 5 ensure that the threads 4 are held parallel to one another, at a height of 12 inches, under a predetermined tension.

Similarly, the threads 4 of the other pair are fixed to the eyelets 3 of the assembly 2 at the corner 1c, pass through the eyelets 3 of the assembly 2 at the corner 1d, and are held against the eyelets 3 of the assembly 2 at the corner la by 4 ounce weights 5. The assemblies 2 are positioned so that the inner thread 4 is spaced from the edges of the pond by about 12 inches.

The threads 4 constitute an effective deterrent to grey herons in a similar manner to the known fixed threads, that is to say a heron will retreat from the pond 1 as soon as it feels a thread against its legs.

Moreover, because the threads 4 of the system of the invention are held in position by the weights 5, and so are not fixed at both ends, the threads will give when contacted (as shown in dashed lines in Fig. 1). With this system, therefore, there is a substantial reduction in the likelihood of the threads 4 being snapped by contact with herons or other larger creatures. Moreover, because the threads 4 are held taut merely under light tension by the weights 5, they are less likely to be blown down in high winds than are the fixed threads of the known system. Another advantage of the system of the invention is that the threads 4 will 'give' to a substantial extent, and so are less likely to trip up, for example, children.

Fig. 4 shows an arrangement for connecting one of the weights 5, the system of Figs. 1 to 3 requiring four such arrangements. This arrangement includes an outer, cylindrical, open-ended tube 11 made of plastics material, and having a diameter of 1.5 inches and a length of 12 inches. This tube 11 is positioned in a complementary hole formed in the pond surround, with its lower end resting on rubble. A plastics connector tube 12 is solvent welded to the upper end of the tube 11, the connector tube constituting a support for an inner tube assembly 13. This assembly 13 has an inner tube 13a made of plastics material, and a cap 13b also made of plastics material, these two items being solvent welded together.

The inner tube 13a has a diameter of 1.25 inches and a length of 10 inches. In use, the rim of the cap 13b rests on the upper edge of the connector tube 12 to support the inner tube 13a within the outer tube 11. The cap 13b is provided with a central aperture 13c through which passes the thread 4 supporting the weight 5. The inner tube 13a has an aperture 13d formed in its closed lower end, this aperture permitting water to escape from the inner tube.

Not only does the arrangement of Fig. 4 conceal the weight 5, but it also facilitates thread replacement in the event of breakage. Thus, should a thread 4 break, the associated weight 5 will fall to the base of its inner tube 13a, from where it is easily recovered by withdrawing the entire assembly 13 from the outer tube 11. A new thread 4 can then be passed through the aperture 13c and fixed to the weight 5, after which the assembly 13 can be replaced inside the outer tube 11.

Fig. 5 shows an alternative form of support rod assembly 22. This assembly has a support rod 22a having a length of 18 inches, and a pair of support arms 22b, each having a length of 3.5 inches. The rod 22a and the arms 22b are made of stainless steel or aluminium, and the arms are co-axial and at right-angles to the rod 2. A stainless steel eyelet 23 is provided at the end of each of the arms 22b. The assembly 22 can be used to support and guide threads 4 either in conjunction with, or instead of, the assemblies 2. In the former case, the assembly 22 could be used to support the threads 4 part way along a long (for example longer than 12 feet) run between two support rod assemblies 2. In the latter case, a plurality of assemblies 22, together with an appropriate number of pairs of threads 4, could be used to protect ponds of non-rectangular shape (see, for example, Figs. 8 to 10).

Figs. 6 to 10 show how the system described above can be adapted to protect ponds of different shapes. Thus, Figs. 6 and 7 show how 'modified' rectangular ponds can be protected using a plurality of support rod assemblies 2, threads (not shown) and weights 5. Similarly, Figs. 8 to 10 show how ponds of other forms can be protected using a plurality of support rod assemblies 22, threads (not shown) and weights 5.

Each of the systems described above is effective in deterring herons from attacking fish in ponds or tanks. The height of the threads 4 is chosen so as to be too high for a heron to step over, but too low for a heron to walk underneath. The support rod assemblies 2, 22 are preferably positioned within a range of 12 to 18 inches from the edge of a pond or tank. If the support rod assemblies are positioned too close to the edge of a pond, a heron could lean over the threads and reach the surface of the pond. On the other hand, if the support rod assemblies are positioned too far away from the edge of a pond, a heron would be able to fly in and land between the protection system and the pond edge.

It will be apparent that the system described above could be modified in a- number of ways. For example, it is not essential to have two sets of threads, one thread (or set of threads) being sufficient to provide protection. Two sets of threads are, however, preferable, as the second (inner) thread(s) provide additional protection should the first (outer) thread(s) break.

Moreover, although black thread is preferable (as it is extremely difficult to see, and so surprises a heron which walks towards a pond protected by the system of the invention) threads of other colours could be used. Again, the weights are not essential, and could be replaced by springs, elastic cords or hydraulic dampers. In each case, a travel of about 6 inches is adequate to permit the threads to travel far enough to deter a heron without significant risk of breakage. It would also be possible to replace the threads 4 and weights 5 by elasticated threads fixed at each end to a respective support rod assembly. In another modification, particularly useful for decorative ponds, small bushes could be planted adjacent to the support rod assemblies to conceal them.

Claims

1. A protection system for protecting fish in a pond, the fish protection system comprising a plurality of support rod assemblies for supporting and guiding thread means so as to extend around the perimeter of the pond at a predetermined height above the pond surround, and at a predetermined distance from the pond perimeter, wherein the thread means is attached to the support rod assemblies in such a manner as to permit the thread means to move laterally towards the pond perimeter through a predetermined distance without the thread means breaking or the support rod assemblies deflecting.

2. A system as claimed in claim 1, wherein the predetermined height lies within the range of from 9 to 15 inches.

3. A system as claimed in claim 2, wherein the predetermined height is substantially 12 inches.

4. A system as claimed in any one of claims 1 to 3, wherein the predetermined distance between the thread means and the pond perimeter is between 12 and 18 inches.

5. A system as claimed in any one of claims 1 to 4, wherein the support rod assemblies support and guide a second thread means.

6. A system as claimed in claim 5, wherein the or each thread means is constituted by a plurality of threads.

7. A system as claimed in any one of claims 1 to 6, wherein each support rod assembly includes a support rod which can be fixed into the pond surround, and at least one support arm extending at right-angles to the support rod.

8. A system as claimed in claim 7 when appendant to claim 6, wherein each support rod assembly includes two support arms.

9. A system as claimed in claim 8, wherein the two support arms are co-axial, and each support arm is provided with an eyelet through which the associated thread can pass.

10. A system as claimed in claim 8, wherein the two support arms lie at right-angles to one another, and each is provided with two eyelets through which associated threads can pass.

11. A system as claimed in claim 6, or in any one of claims 7 to 10 when appendant to claim 6, wherein one end of each thread is fixed to a first support rod assembly, the other end of said thread being held against a second support rod assembly by means of a weight attached to said other end.

12. A system as claimed in claim 6, or in any one of claims 7 to 11 when appendant to claim 6, wherein each thread is a black braided terylene thread.

13. A fish protection system substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.