Method and system for generating a bio-inspired signal, use of such a signal

Abstract

Method and system for generating a bio-inspired signal, use of such a signal The invention relates to a method for generating a bio-inspired signal. According to such a method, a transmission device (100e) implementing an output transducer (100e2) executes: - an emission, by the output transducer, of an acoustic signal, called an incident signal, which is a function of an echolocation click emitted by an animal of the odontocete type in a natural environment, the incident signal being emitted in the direction of a net (110) comprising at least one dead odontocete (120) entangled inside. A reception device (100r) implementing an input transducer (100r2) executes: - a reception, by the input transducer, of a return signal corresponding to the reflection of the incident signal on the net. The bio-inspired signal is a function of the return echo. ABSTRACT FIGURE: [Fig.1]

Description

Title of the invention: Method and system for generating a bio-inspired signal, use of such a signal Field of the invention

[0001] The field of the invention is that of fishing.

[0002] The invention relates more particularly to a method for generating a bio-inspired signal which can be used in the context of fishing using a fishing net.

[0003] The invention thus has applications, in particular, but not exclusively, during artisanal or industrial fishing with nets. Prior art and its drawbacks

[0004] Accidental catches in fisheries involving one or more nets are the main direct cause of mortality of marine mammals worldwide. Most of these events involve pinnipeds and cetaceans.

[0005] One of the methods developed in recent decades to try to prevent accidental captures of cetaceans, in particular odontocetes (i.e. toothed cetaceans with sonar) such as dolphins and porpoises, is the use of acoustic repellent transmitters (called "pingers" in English), which are attached to fishing nets.

[0006] More specifically, repellent transmitters emit acoustic signals whose objective is to repel odontocetes from nets. These devices use relatively energetic and high-frequency signals, in the frequency range of the animals' hearing sensitivity. However, the effectiveness of repellent transmitters is heterogeneous depending on different factors such as the species, the fishing gear used (e.g. different types of nets) or the geographical areas. Furthermore, behavioral studies have reported negative effects on certain species of dolphins such as a decrease in the number of signals associated with echolocation activity (i.e. signals allowing objects to be located in their environment) and a decrease in the number of vocalization signals (i.e. signals allowing communication between individuals), which suggests a reduced ability to detect a net and a higher probability of being captured.

[0007] Finally, if some repellent transmitters are widely deployed in space (i.e. by many fishing vessels and / or installed on significant lengths of nets), they could create exclusion zones from the animal habitat due to noise pollution.

[0008] It is therefore necessary to develop new, more effective acoustic devices, without undesirable effects, in order to limit accidental captures of cetaceans of the odontocete type, e.g. such as dolphins. Statement of the invention

[0009] In one embodiment of the invention, a method for generating a bio-inspired signal is provided. According to such a method, a transmission device implementing an output transducer performs:

[0010] - an emission, by the output transducer, of an acoustic signal, called signal incident, function of a recording of an echolocation click emitted by an animal of the odontocete type in a natural environment, the incident signal being emitted in the direction of a net containing at least one dead odontocete entangled inside.

[0011] A receiving device implementing an input transducer performs:

[0012] - a reception, by the input transducer, of a return signal corresponding to the reflection of the incident signal on the net.

[0013] The bio-inspired signal is a function of the return echo.

[0014] Thus, the invention proposes a new and inventive solution for limiting accidental captures of marine mammals of the odontocete type (i.e. toothed cetaceans equipped with sonar).

[0015] To do this, it is proposed, unlike the signals used in known repellent transmitters, to implement a bio-inspired signal, directly interpretable by the odontocete, based on an echolocation click of such an odontocete reflected on a net in which a dead odontocete is entangled (of the same type as the odontocete at the origin of the echolocation click or not).

[0016] Indeed, the sonar of odontocetes is very efficient and allows the animal to have precise information on the nature of the object at the origin of the return signal, e.g. on the thickness of the skin of the dead animal entangled in the net, the material of which it is composed, etc. The return echo of an echolocation click can be interpreted by any individual within a given species of odontocete. In this way, an odontocete of the same species as the odontocete at the origin of the echolocation click used can interpret the bio-inspired signal generated according to the present invention and obtain information on the presence in the vicinity of a net, e.g. a fishing net, and the associated danger of death. The odontocete interpreting the bio-inspired signal is thus informed of the danger of approaching such a net when the bio-inspired signal generated according to the present invention is broadcast from, or in the vicinity of, such a net.The efficiency of odontocetes repulsion is thus improved compared to known repellent transmitter techniques via the information included in the bio-inspired signal which does not . does not generate any distancing behavior with stress or disruption of the odontocete's sonar.

[0017] In some embodiments, the transmission of the incident signal comprises:

[0018] - a memory reading of digital samples of the click recording echolocation;

[0019] - a digital-to-analog conversion of samples as a function of the samples digital echolocation click recordings delivering an analog click signal; and

[0020] - an amplification of a signal depending on the analog click signal delivering a amplified signal.

[0021] The incident signal is a function of the amplified signal.

[0022] In some embodiments, the amplified signal is provided to the output transducer providing the incident signal.

[0023] In some embodiments, the output transducer is an omnidirectional spherical piezoelectric output transducer.

[0024] In some embodiments, receiving the return echo comprises:

[0025] - a capture of the return signal by the input transducer delivering a return signal analog;

[0026] - an analog-to-digital conversion of a signal that is a function of the return signal analog delivering digital samples, called return samples; and

[0027] - a writing in memory of final digital samples functions of the return samples.

[0028] The bio-inspired signal is a function of the final digital samples.

[0029] In some embodiments, receiving the return echo comprises:

[0030] - a filtering of the return samples delivering filtered digital samples; and

[0031] - an amplification of the filtered digital samples delivering the samples final digital.

[0032] In certain embodiments, the net comprising the at least one dead odontocete is placed in the open sea or in a basin filled with water and:

[0033] - a distance, called the emission distance, between, on the one hand, the output transducer and, on the other hand, the net or the dead odontocete is less than a first distance between, on the one hand, the output transducer and, on the other hand, the surface of the water; and / or

[0034] - the emission distance is less than a second distance between, on the one hand, the output transducer and, on the other hand, the water bottom.

[0035] In certain embodiments:

[0036] - a distance, called reception distance, between, on the one hand, the input transducer and, on the other hand, the net or dead odontocete is less than a third distance between, on the one hand, the input transducer and, on the other hand, the water surface; and / or

[0037] - the reception distance is less than a fourth distance between, on the one hand, the input transducer and, on the other hand, the water bottom.

[0038] Thus, the rebound effects linked to the water surface and the water bottom, and therefore the parasitic echoes in the return signal, are minimized.

[0039] In certain embodiments:

[0040] - a ratio between, on the one hand, the emission distance and, on the other hand, the first distance, is less than or equal to three tenths; and / or

[0041] - a ratio between, on the one hand, the emission distance and, on the other hand, the second distance, is less than or equal to three tenths; and / or

[0042] - a ratio between, on the one hand, the reception distance and, on the other hand, the third distance is less than or equal to three tenths; and / or

[0043] - a ratio between, on the one hand, the reception distance and, on the other hand, the fourth distance is less than or equal to three tenths.

[0044] Thus, the return signal is received by the input transducer with sufficient amplitude to allow simple detection while minimizing the rebound effects linked to the water surface and the water bottom, and therefore the parasitic echoes in the return signal.

[0045] The invention also relates to a use of a bio-inspired signal generated by implementing the generation method as described previously (according to any one of the aforementioned embodiments) for keeping animals of said odontocete type away from a net.

[0046] The invention also relates to a system for generating a bio-inspired signal. Such a system comprises a transmission device implementing an output transducer, the transmission device being configured to execute:

[0047] - an emission, by the output transducer, of an acoustic signal, called signal incident, function of an echolocation click emitted by an animal of the odontocete type in the natural environment, the incident signal being emitted in the direction of a net containing at least one dead odontocete entangled inside.

[0048] The system further comprises a receiving device implementing an input transducer, the receiving device being configured to perform:

[0049] - a reception, by the input transducer, of a return signal corresponding to the reflection of the incident signal on the net.

[0050] The bio-inspired signal is a function of the return echo. List of figures

[0051] Other aims, characteristics and advantages of the invention will appear more clearly on reading the following description, given as a simple illustrative, and non-limiting, example, in relation to the following figure:

[0052] [Fig.l] represents a system for generating a bio-inspired signal, the system comprising a transmitting device and a receiving device configured to implement the generation method of [Fig.2] according to an embodiment of the invention;

[0053] [Fig. 1a] represents an example of the structure of the transmission device of the system of [Fig. 1] according to an embodiment of the invention;

[0054] [Fig. 1b] represents an example of structure of the receiving device of the system of [Fig.l] according to an embodiment of the invention;

[0055] [Fig.2] represents the steps of a method for generating a bio-inspired signal according to an embodiment of the invention;

[0056] [Fig.2a] represents steps of the emission step of the generation method of [Fig.2] according to an embodiment of the invention;

[0057] [Fig.2b] represents steps of the reception step of the generation method of [Fig.2] according to an embodiment of the invention;

[0058] [Fig.3] represents an echolocation click emitted by a short-beaked common dolphin in its natural environment;

[0059] [Fig.4] represents the bio-inspired signal generated by implementing the generation method of [Fig.2] from the echolocation click of [Fig.3] according to an embodiment of the invention.

[0060] Detailed description of embodiments of the invention

[0061] We now present, in relation to [Fig.l] a system 100 for generating a bio-inspired signal according to an embodiment of the invention.

[0062] More particularly, the system 100 comprises a transmission device 100e configured to generate and transmit an acoustic signal, called incident signal, depending on a recording of an echolocation click emitted by an animal of the odontocete type in a natural environment.

[0063] To do this, the transmission device 100e comprises a device 100el for generating an analog click signal and an output transducer 100e2 delivering the incident signal from the analog click signal. For example, the device 100el for generating the analog click signal comprises ([Fig. la]) a random access memory 100el3 (for example a RAM memory), a processing unit 100el2 equipped for example with a processor, and controlled by a computer program stored in a read-only memory 100el1 (for example a ROM memory or a hard disk). Upon initialization, the code instructions of the computer program are for example loaded into the random access memory 100el3 before being executed by the processor of the processing unit 100el2.

[0064] The read-only memory 100el 1 stores, for example, digital samples of the echolocation click recording. Such recordings are, for example, available for some species in online databases on the internet, as online supplementary material in scientific publications, or directly from scientists. Alternatively, such recordings can be measured in situ with a hydrophone in the natural environment in the presence of the odontocete emitting the echolocation click. The bandwidth of such an echolocation click depends on the odontocete in question. For example, for some species the echolocation click extends over a restricted frequency band, e.g. over the band extending from 120 kHz to 140 kHz for some porpoises. Generally speaking, these are frequencies relevant to ultrasound.

[0065] Returning to [Fig.1a] a digital (or digital) analog converter 100el4 (or DAC) converts samples based on the samples of the echolocation click recording into an analog signal so as to deliver the analog click signal supplied to the output transducer 100e2. In certain embodiments, the device 100el comprises an amplifier for amplifying the signal delivered by the DAC. The analog click signal supplied to the output transducer 100e2 is thus the amplified signal delivered by the amplifier. The output transducer 100e2 is for example an omnidirectional spherical piezoelectric output transducer.

[0066] The transmission device 100e is more particularly configured to carry out certain steps of the generation method of [Fig.2] (according to any one of the embodiments and / or variants described below in relation to [Fig.2], [Fig.2a] and [Fig.2b]).

[0067] This [Fig.1a] illustrates only one particular way, among several possible ways, of producing the generation device 100el so that it performs all or part of the steps of the generation method of [Fig.2] (according to any one of the embodiments and / or variants described below in relation to [Fig.2], [Fig.2a] and [Fig.2b]). For example, some of these steps can be performed indifferently on a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or on a dedicated computing machine (for example a set of logic gates such as an FPGA or an ASIC, or any other hardware module).

[0068] In the case where the generation device 100el comprises a reprogrammable computing machine, the corresponding program (i.e. the sequence of instructions) may be stored in a removable storage medium (such as for example a CD-ROM, a DVD-ROM, a USB key) or not, this storage medium being partially or totally readable by a computer or a processor.

[0069] Returning to [Fig.l], the incident signal is emitted towards a net 110, e.g. a fishing net type net, comprising one (or more) dead odontocete 120 entangled inside. Furthermore, the system 100 comprises a receiving device 100r (eg a digital hydrophone) configured to receive and process a return signal corresponding to the reflection (ie a return signal corresponding to the echo) of the signal incident on the net 110 comprising the dead odontocete (or odontocetes) 120 entangled inside.

[0070] To do this, the receiving device 100r comprises eg an input transducer 100r2 (or hydrophone) delivering an analog return signal from the return signal and a device 100rl for processing the analog return signal. For example, the processing device 100rl comprises ([Fig.lb]) a random access memory 100rl3 (for example a RAM memory), a processing unit 100rl2 equipped for example with a processor, and controlled by a computer program stored in a read-only memory 100rl1 (for example a ROM memory or a hard disk). On initialization, the code instructions of the computer program are for example loaded into the random access memory 100rl3 before being executed by the processor of the processing unit 100rl2.

[0071] For example, an analog-digital converter 100rl4 (or ADC) converts the analog return signal and delivers digital samples, called return samples. Final digital samples that are functions of the return samples are written into the RAM 100rl3. For example, filtering and / or amplification type processing is applied to the return samples to obtain the final digital samples. The bio-inspired signal corresponds to the final digital samples, or at least is a function of the final digital samples, e.g., in the case where additional processing is applied to the final digital samples to obtain the bio-inspired signal as described below in relation to [Fig.2], [Fig.2a] and [Fig.2b].

[0072] The processing device 1001 is more particularly configured to carry out certain steps of the method for generating [Fig.2] (according to any one of the embodiments and / or variants described below in relation to [Fig.2], [Fig.2a] and [Fig.2b]).

[0073] This [Fig.lb] illustrates only one particular way, among several possible ways, of producing the processing device 100rl so that it performs all or part of the steps of the generation method of [Fig.2] (according to any one of the embodiments and / or variants described below in relation to [Fig.2], [Fig.2a] and [Fig.2b]). For example, some of these steps can be performed indifferently on a reprogrammable computing machine (a PC computer, a DSP processor or a microcontroller) executing a program comprising a sequence of instructions, or on a dedicated computing machine (for example a set of logic gates such as an FPGA or an ASIC, or any other hardware module).

[0074] In the case where the processing device 1001 comprises a reprogrammable computing machine, the corresponding program (i.e. the sequence of instructions) may be stored in a removable storage medium (such as for example a CD-ROM, a DVD-ROM, a USB key) or not, this storage medium being partially or totally readable by a computer or a processor.

[0075] Returning to [Fig.l], in order to implement the method of [Fig.2] (according to any one of the embodiments and / or variants described below in relation to [Fig.2], [Fig.2a] and [Fig.2b]), the net 110 comprising the dead odontocete 120 (or odontocetes 120) is placed in the open sea or in a basin filled with water, e.g. filled with sea water, brackish water or fresh water.

[0076] In the present embodiment the output transducer 100e2 and the input transducer 100r2 are arranged substantially three meters from the net 110. Thus, the return signal is received by the input transducer 100r2 with sufficient amplitude to allow simple detection.

[0077] In some embodiments, the output transducer 100e2 and the input transducer 100r2 are disposed at a sufficient distance from the water surface 130 and the water bottom 140 to facilitate the management of unwanted echoes. For example, the output transducer 100e2 is configured to:

[0078] - that a distance, called emission distance, between, on the one hand, the transducer 100e2 output and, on the other hand, the net 110 or the dead odontocete 120 is less than a first distance between, on the one hand, the output transducer 100e2 and, on the other hand, the surface 130 of the water; and / or

[0079] - that the emission distance is less than a second distance between, on the one hand, the 100e2 output transducer and, on the other hand, the 140 water bottom.

[0080] Furthermore, the input transducer 100r2 is configured to:

[0081] - that a distance, called reception distance, between, on the one hand, the transducer 100r2 input and, on the other hand, the net 110 or the dead odontocete 120 is less than a third distance between, on the one hand, the input transducer 100r2 and, on the other hand, the surface 130 of the water; and / or

[0082] - that the reception distance is less than a fourth distance between, on the one hand, the input transducer 100r2 and, on the other hand, the bottom 140 of the water.

[0083] Thus, the rebound effects linked to the surface 130 of the water and the bottom 140 of the water, and therefore the parasitic echoes in the return signal, are minimized.

[0084] According to some implementations, the first distance and / or the second distance is / are greater than or equal to ten meters. Similarly, according to some implementations, the third distance and / or the fourth distance is / are greater than or equal to ten meters. Furthermore, according to some implementations, the transmission distance is less than or equal to three meters. Similarly, according to some implementations, the reception distance is less than or equal to three meters.

[0085] Thus, in certain embodiments:

[0086] - the ratio between, on the one hand, the emission distance and, on the other hand, the first distance, is less than or equal to three tenths (3 / 10); and / or

[0087] - the ratio between, on the one hand, the emission distance and, on the other hand, the second distance, is less than or equal to three tenths (3 / 10); and / or

[0088] - the ratio between, on the one hand, the reception distance and, on the other hand, the third distance is less than or equal to three tenths (3 / 10); and / or

[0089] - the ratio between, on the one hand, the reception distance and, on the other hand, the fourth distance is less than or equal to three tenths (3 / 10).

[0090] Thus, the return signal is received by the input transducer 100r2 with sufficient amplitude to allow simple detection while minimizing unwanted echoes in the return signal.

[0091] However, in other implementations, the output transducer 100e2 and the input transducer 100r2 are arranged in other configurations relative to the water surface 130 and the water bottom 140.

[0092] In some implementations, the output transducer 100e2 and the input transducer 100r2 are remote from the generation device lOOel and the processing device lOOrl respectively. For example, the output transducer 100e2 is electrically connected to the generation device 100e 1 via an electrical cable. Similarly, the input transducer 100r2 is for example electrically connected to the processing device lOOrl via another electrical cable. In such configurations, the output transducer 100e2 as well as the input transducer 100r2 are immersed to implement the method of [Fig.2] (according to any one of the embodiments and / or variants described below in relation to [Fig.2], [Fig.2a] and [Fig.2b]). On the contrary, the generation device lOOel and the treatment device lOOrl remain out of the water in such cases (egthe generation device lOOel and the processing device lOOrl are implemented in the form of a remote computer).

[0093] We now present, in relation to [Fig.2], a method for generating a bio-inspired signal according to an embodiment of the invention.

[0094] More particularly, during a step E200 executed by the emission device 100e, the output transducer 100e2 emits the incident signal depending on a recording of an echolocation click emitted by an animal of the odontocete type in a natural environment. As described above, the incident signal is emitted in the direction of the net 110 comprising one (or more) dead odontocete 120 entangled inside.

[0095] During a step E210 executed by the reception device 100r, the input transducer 100r2 receives the return signal corresponding to the reflection of the incident signal on the net 110.

[0096] The bio-inspired signal is a function of the return echo. In this way, the bio-inspired signal generated via the implementation of the present generation method (according to any one of the embodiments and / or variants described in relation to [Fig.2], [Fig.2a] and [Fig.2b]) comprises the information of presence in the vicinity of a net with one (or more) dead odontocete 120. Furthermore, the bio-inspired signal can be interpreted by an odontocete of the same species as the one at the origin of the echolocation click. The bio-inspired signal can thus be used to alert an odontocete of this same species of a danger nearby and thus move it away, e.g. from a fishing net. To do this, the bio-inspired signal is for example broadcast by a beacon placed on the net 110.Furthermore, it seems more consistent to use such a bio-inspired signal if the dead odontocete (or odontocetes) 120 used to generate the signal is of the same species as the one that originated the echolocation click. Indeed, in this case, the information included in the bio-inspired signal is all the more relevant for the odontocete of the species in question. However, this approach is not necessary and one (or more) dead odontocete 120 of a given species (or several types) can be used even if the species in question is not the same as that of the odontocete that originated the echolocation click.

[0097] In the embodiment of [Fig.2a], step E200 comprises:

[0098] - a step E200a in which the transmission device 100e executes a reading into 100el3 memory of digital samples of the echolocation click recording;

[0099] - a step E200b in which the transmission device 100e performs a conversion digital analog of samples depending on the digital samples of the recording of the echolocation click delivering the analog click signal; and

[0100] - a step E200c in which the transmission device 100e executes a amplification of a signal depending on the click signal delivering an amplified signal.

[0101] The incident signal is a function of the amplified signal. For example, the amplified signal is supplied to the output transducer 100e2 delivering the incident signal.

[0102] However, in other embodiments, other signal processing steps may be envisaged in order to generate the incident signal, e.g. shaping adapted to the propagation channel, scaling, insertion of a preamble so as to facilitate detection of the return signal, etc.

[0103] In the embodiment of [Fig.2b], step E210 comprises:

[0104] - a step E210a in which the receiving device 100r executes a capture of the return signal by the 100r2 input transducer delivering the analog return signal;

[0105] - a step E210b in which the receiving device 100r executes a analog-to-digital conversion of a signal as a function of the analog return signal delivering digital samples, called return samples; and

[0106] - a step E210c in which the receiving device 100r executes a write in memory 100rl3 of the final digital samples functions of the return samples.

[0107] The bio-inspired signal is a function of the final digital samples. For example, the return samples are post-processed in order to obtain the final digital samples. In such cases, step E210 comprises for example:

[0108] - a filtering of the return samples delivering filtered digital samples; and

[0109] - an amplification of the filtered digital samples delivering the samples final digital.

[0110] However, in other embodiments, other signal processing steps may be envisaged in order to generate the final digital samples, eg synchronization, equalization of the propagation channel, etc.

[0111] By way of illustration, [Fig. 3] represents an echolocation click emitted by a short-beaked common dolphin in a natural environment. [Fig. 4] represents the bio-inspired signal generated by implementing the method for generating [Fig. 2] from the echolocation click of [Fig. 3]. More particularly, in the present case, the implementation of the method was carried out in the open sea on depths of twenty meters, in calm seas at slack tide. More particularly, the net 110 comprising a dead dolphin 120 (here a short-beaked common dolphin previously found stranded on a beach) on the one hand, and the output transducer 100e2 and the input transducer 100r2 on the other hand, were suspended to the port and starboard sides of a boat. The net 110 was thus placed approximately three meters apart from the transducers 100e2, 100r. A 110 nylon trammel monkfish net with a mesh size of two hundred and twenty millimeters was used.The dimensions of net 110 were approximately four meters long and two meters high. Net 110 was weighted in three places (ends and middle) with lead and chains suspended by ropes three meters below the net in order to dissociate the acoustic signature of the latter and isolate them from that of net 110 during post-processing of the return signals. The bio-inspired signal thus obtained ([Fig.4]) can be used to preferentially keep common dolphins away via the emission of the signal e.g. by one (or more) acoustic beacons submerged along net 110.

Claims

Claims

1. Method for generating a bio-inspired signal, characterized in that a transmission device (100e) implementing an output transducer (100e2) executes: - a transmission (E200), by the output transducer, of an acoustic signal, called incident signal, which is a function of a recording of an echolocation click emitted by an animal of the odontocete type in a natural environment, the incident signal being emitted in the direction of a net (110) comprising at least one dead odontocete (120) entangled inside, and in that a reception device (100r) implementing an input transducer (100r2) executes: - a reception (E210), by the input transducer, of a return signal corresponding to the reflection of the incident signal on the net, the bio-inspired signal being a function of the return echo.

2. Method according to claim 1, in which the emission of the incident signal comprises: - a reading (E200a) in memory of digital samples of the recording of the echolocation click; - a digital-analog conversion (E200b) of samples depending on the digital samples of the recording of the echolocation click delivering an analog click signal; and - an amplification (E200c) of a signal depending on the analog click signal delivering an amplified signal, the incident signal being a function of the amplified signal.

3. A method according to claim 2, wherein the amplified signal is supplied to the output transducer providing the incident signal.

4. A method according to any one of claims 1 to 3, wherein the output transducer is an omnidirectional spherical piezoelectric output transducer.

5. Method according to any one of claims 1 to 4, in which the reception of the return echo comprises: - a capture (E210a) of the return signal by the input transducer delivering an analog return signal; - an analog-digital conversion (E210b) of a signal which is a function of the analog return signal delivering digital samples, called return samples; and - a writing (E210c) in memory of final digital samples which are functions of the return samples, the bio-inspired signal being a function of the final digital samples.

6. Method according to claim 5, wherein the reception of the return echo comprises: - filtering the return samples delivering filtered digital samples; and - amplification of the filtered digital samples delivering the final digital samples.

7. Method according to any one of claims 1 to 6, in which the net comprising the at least one dead odontocete is placed in the open sea or in a basin filled with water, and in which: - a distance, called the emission distance, between, on the one hand, the output transducer and, on the other hand, the net or the dead odontocete is less than a first distance between, on the one hand, the output transducer and, on the other hand, the surface (130) of the water; and / or - the emission distance is less than a second distance between, on the one hand, the output transducer and, on the other hand, the bottom (140) of the water.

8. Method according to any one of claims 1 to 7, in which: - a distance, called reception distance, between, on the one hand, the input transducer and, on the other hand, the net or the dead odontocete is less than a third distance between, on the one hand, the input transducer and, on the other hand, the surface of the water; and / or - the reception distance is less than a fourth distance between, on the one hand, the input transducer and, on the other hand, the bottom of the water.

9. Method according to claim 8 in that it depends on 7, in which: - a ratio between, on the one hand, the transmission distance and, on the other hand, the first distance, is less than or equal to three tenths; and / or - a ratio between, on the one hand, the transmission distance and, on the other hand, the second distance, is less than or equal to three tenths; and / or - a ratio between, on the one hand, the reception distance and, on the other hand, the third distance is less than or equal to three tenths; and / or - a ratio between, on the one hand, the reception distance and, on the other hand, the fourth distance is less than or equal to three tenths.

10. Use of a bio-inspired signal generated by implementing the method according to any one of claims 1 to 9 to keep animals of said odontocete type away from a net.

11. System for generating a bio-inspired signal, characterized in that it comprises a transmission device (100e) implementing an output transducer (100e2), the transmission device being configured to execute: - an emission (E200), by the output transducer, of an acoustic signal, called incident signal, a function of an echolocation click emitted by an animal of the odontocete type in a natural environment, the incident signal being emitted in the direction of a net (110) comprising at least one dead odontocete (120) entangled inside, and in that it comprises a receiving device (100r) implementing an input transducer (100r2), the receiving device being configured to perform: - reception (E210), by the input transducer, of a return signal corresponding to the reflection of the incident signal on the net, the bio-inspired signal being a function of the return echo.

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