Many different methods to attract fish or other marine prey animals are known. For example, patent publication US 4,959, 919 describes a bait for fish equipped with a light source driven by a salt water battery. Many variations exist, where fish is lured to a cage, a net, a boat, and so on, by using bait food, light, sound, and so on, which is described in amongst others NO 36629, NO 54816, US 4,955, 005, US 5,282, 178, US 6,098, 331, and US 1,381, 203. Some of these methods are considered to function well, and have been developed somewhat further.

Other methods and devices are described in CA A1 2.120. 969, WO A1 02089568, WO A1 0107829, US 6,203, 170, and US 5,175, 951.

It is also known in the subject area that big-scale research is done regarding catching krill for commercial purposes. The problem with catching krill is that it is difficult to gather enough krill at one spot to exploitably catch krill. It has been tried to collect krill out of the water by using, amongst others, nets, pumps, etc. , without much success. At this time, a team consisting of thirteen persons all having a doctor degree is performing

a study in Trondheimsfjorden, with the purpose to find a solution to exploitably catch krill. Until this day, no promising results were obtained through this study.

Further, breeding farms are known for, for example, fish, where large quantities of fish are put in a seine bag, and where the fish is fed with artificially provided fish food, which is especially composed for the fish to grow quickly. This brings along a large amount of biomass in the water, and causes in this way that the water is polluted.

Problems with the solutions where light is used to attract fish, to for example a boat or a net, is that it costs much energy and that it causes serious light pollution in large areas in the sea. Further, it is with this method not possible to attract fish selectively.

According to the above mentioned patent documents, and generally in the subject area, it is known to use light in a certain frequency and intensity to attract marine organisms.

However, no products or methods are known which in addition give off pulsating light.

The light emitted by whole schools/groups of fish, or other marine organisms having a light organ, is often pulsating. The use of light in accordance with prior art, among which the above mentioned, do not make use of this pulsating emission of light.

80-90% of all plankton species, and also a large number of other marine organisms like for example fish, have one or several light organs. These light organs emit light in a particular frequency, colour, and/or intensity, depending on which species it is. For Krill, for example, which eats plankton, uses its light organ for amongst others school gathering.

The present invention provides considerably improved methods, as light having a specific frequency, colour and/or intensity is employed.

In this application, the words frequency, colour, and intensity will be used. For the sake of clarity it should be mentioned that by the word'frequency', the frequency of the

pulsating emission of the light is meant, which is not described in prior art. With'colour', the wavelength of the light is meant.

The object of the present invention is to imitate those species which emit light, by emitting light in the same frequency, colour, and intensity, for therewith to attract organisms that eat the species emitting the light. Additionally, the species emitting the light can be attracted and used as fodder. The frequency, colour, and intensity of the light emitted by a specific species can be measured, and so programmed in an artificial light organ according to the invention, which then emits the same light. Organisms like krill, fish, and so on, will be attracted by this, and can then for example be pumped or caught out of the water, or it can be lured into a cage. Further, the invention triggers the eating instinct.

A further advantage is that in the invention a saltwater battery is used. Advantages with this is amongst others that it is extremely cheap to produce, it does, unlike common batteries, not pollute, it is easier in use by that no battery shift is necessary, it switches itself off when lifted from out of the water, and it lasts until one of the electrodes, for example the magnesium electrode, is consumed.

Further it is extremely advantageous to use a saltwater battery in this application, as a magnetic field is formed inside and around the outside of the device. The magnetic field around the device will not arise when a common battery is used. The advantage with this magnetic field is that many marine organisms are extremely sensitive for such magnetic fields, and they are attracted further because of this field.

Krill which is attracted by the light organ according to the present invention can amongst others be used as natural bait for fish, which in this way can be lured into a cage, net, and so on.

The light organ can further be employed in a seine with farmed fish, removing or reducing the necessity for artificial addition of fish fodder.

Anglers can use the light organ to more selectively attract a specific fish species.

An advantage with the present invention is that it more effectively and more selectively than prior art attracts krill, fish, and other organisms.

A further advantage is that the invention is more environmental friendly than known solutions, as it carries along considerably less light, sound, or biomass pollution than prior art solutions do.

Further, the solution according to the present invention is cheap and easy to produce.

The price for, for example, an angler's bait will be within the normal price range for angler's bait.

The invention has been tested as angler's bait in the North Sea, and it has been found out that it has a significantly better effect than prior art solutions, even though the tests were performed with prototypes which were not optimised for the specific use. It is consequently expected that a further optimisation of the light organ will result in an even more effective functionality of the invention. As mentioned, the invention will give an electric/magnetic field around the light organ, as all living organisms have, something which triggers the snatch instinct in fish.

The device according to the invention is characterised by the characterising part of claim 1, by that the electronic circuit is arranged to deform energy from the energy source to a wave length with a specific frequency, whereby the light source frequency is adapted to correspond to a specific light organ's frequency, and by that the energy source comprises a saltwater battery comprising two or more electrodes, of which at least one electrode is made of an electrolyte.

The method according to the invention is characterised by the characterising part of claim 7, by that it comprises the following steps: to determine the frequency and/or

colour and/or intensity of the light emitted from the light organ of the organism to be imitated; to set a similar frequency and/or colour and/or intensity in a light emitting member in the light emitting device.

Preferred embodiments are characterised by the independent claims 2-6 and 8-10.

The invention can preferably be used for purposes described in claims 11-13.

The invention will now be described using the attached figures, where: Figure 1 shows a block diagram of one preferred embodiment of the invention; Figure 2 shows an example of a preferred practical embodiment of a fishing lure ; Figure 3 & 4 show the front and back sides of a preferred practical embodiment of a circuit board for use in the invention.

A general embodiment of the invention comprises an energy source, a circuit board with electronics which convert the energy to a predetermined frequency, which is dependent on the purpose and a light emitting light in the same frequency given by the electronics on the circuit board.

In a preferred embodiment of the invention a saltwater battery is used as energy source.

The saltwater battery in a test device uses electrodes of magnesium and cobber, even though the use of many other materials is possible. It is known that electrodes made of for example magnesium and cobber in saltwater render a voltage over the electrodes, and that this voltage can be used for for example provide electricity to a light bulb. The magnesium is slowly consumed, and the working life of the electrode can be adapted to the purpose by changing the composition or shape/size of it.

In a later embodiment it was found that en electrode made of iron and plated with a thin gold coating renders better results than cobber, and that it does not corrode in sea water. The cobber electrode which corrodes can render problems with the sealing, so that sea water can enter the device. The iron electrode coated with a gold film is cheaper, more effective, and not subject to corrosion, that is, wear.

Tables exist which indicate how large a voltage is caused by different combinations of materials the electrodes are made of. It can thus be determined ahead how much voltage a specific electrode combination will render. The electronics on the circuit board in the present invention changes the voltage over the electrodes in such a way that the effect and voltage of energy developed by the saltwater battery is improved.

The circuit board according to a preferred embodiment of the invention, which is shown in figure 3 and in figure 4, comprises the following parts: C = capacitator, S = diode, L = coil, Q = transistor, R = resistance.

An example of one assembly is shown in the following table : No. qt. component Size Comp. type 1 2 C1, C2 1 nF 0603 2 2 C3, C51uF0805 3 2 C6, C4 10uF 1206 4 1 D1 EL12-215UBC 0805 5 1 D2 BAT54W SOT-323 6 1 L1 1000uH 1812 7 5 Q1, Q2, Q3, Q4, Q5 BC847CW SOT-323 8 2 R1, R4 1 OK 0603 9 1 R2 12K 0603 10 1 R3 75K 0603 11 2 R5, R7 330K 0603 12 1 R6 4. 7M 0603 13 1 R8 1 K 0603

As light source, one or more diode lights can be used, according to a preferred embodiment of the invention.

Tests with the invention were performed in the following way: Angling : tests were performed by fishing over several periods with two identical fishing equipments on the same place and at the same time, where one of the equipments had the light organ attached.

Bow-net and fish trapping: Tests were performed by professional fishermen where every second of the bow-nets and fish traps were set with usual bait, and every other second with only the light organ according to the invention.

The tests show an effective improvement of catch when the light organ is used, in respect to when it is not used.

Some of the areas of application the invention is directed to are: fishing lures, jigs, fishing hooks; line fishing; bow-nets and fishing traps; lure lights for luring fodder- organisms to bow-nets/cages/breeding nets; luring lights on fishing nets/seines/dragnets; environmental monitoring, that is, fish in a bow net is fed with animal plankton over a long period of time in a polluted area, where after the pollution is measured.

In most fishing related applications the invention constitutes an effective tool, where no bait is used, where no scavengers are attracted, where it is possible to fish selective and controllable, which is environmentally friendly, which provides natural feeding under natural conditions, which lures fish to the end user, which can be applied in crustacean breeding and other breeding, and which is cheap to produce.

Different technical solutions have been utilised where saltwater is used as an electrolyte. For example, Simrad (1 has a large saltwater battery. This is built up, and

uses saltwater, for a totally different purpose. The battery in this case is used for offshore related purposes, to charge a standard lead storage battery or other batteries.

In use, traditional saltwater batteries have a sincere limitation with respect to volume, size and costs for the units, versus the invention's simplicity and miniaturised size. All materials suitable for electrode use can be applied.

Figure 1 shows a first preferred embodiment for a unit in accordance with the invention, where a saltwater battery is applied to produce the required voltage.

1. Cobber or iron with gold film-used as a cathode in the saltwater battery.

2. Magnesium-is used as the anode in the saltwater battery.

3. Imbedded electronic circuit board.

4. LED-frequency, colour and intensity of the light can be varied dependent on use.

5. Sound-the unit can also be equipped with a programmable sound generator.

Sound recordings from different fish types can be programmed for selective tools.

6. Surrounding saltwater is used as electrolyte.

Figure 2 shows a drawing of what the unit can look like in practice.

Other areas for use which can be thought of are directed towards tagging of buoys and beacons along the coast (international light codes), marking lights for divers, emergency lights, marking lights, lights for life jackets and rescue equipment.

Further the invention can be combined with one or more solutions to attract organisms, so that possibly a double functionality is obtained. For example, a unit can be provided on a fishing lure, which unit produces the sound of eating fish.

A preferred embodiment of the invention comprises a housing comprising two parts (10) with a hole (60). Through the hole (60) one electrode (30) protrudes, for example the

cobber electrode. The electrode (30) is pressed, glued, or in other ways fixed to the hole (60), so that it is water proof.

Between the two housing parts (10) the other electrode (20) is arranged, for example the magnesium electrode. On the ends of the electrode (20) a hole (50) is provided, for attachment of for example a line. In the middle of the electrode (20) a larger, for example square, hole (40) is provided, which shall accommodate the circuit board as for example in figure 3 and figure 4. The LED/LED's are preferably arranged on the circuit board.

The two housing parts (10) are shaped in a way that they can be clicked together, with the electrode (20) squeezed between them. The whole should be water proof, which is obtained with for example a washer, glue, silicon, o-ring, etc.

The frequency of the LED can be set in known ways, for example by selecting the proper capacitor, resistor, or other known electronic components. Further, it can be a more complex embodiment, where the user himself can set the frequency, and therewith chose an area of use, or the species to be attracted.