Method and system for generating a bio-inspired signal, use of such a signal
A bio-inspired acoustic signal system using echolocation clicks from entangled whales generates a deterrent signal for toothed whales, addressing the inefficiencies of traditional repellent emitters by effectively alerting cetaceans to nets while minimizing environmental noise and behavioral impacts.
Patent Information
- Application Number
- FR2023014805
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-12-21
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2043-12-21
AI Technical Summary
Existing acoustic repellent emitters for preventing accidental capture of toothed whales in fishing nets are ineffective due to species-specific and geographical variations, causing noise pollution and behavioral disturbances, and do not effectively deter cetaceans from nets.
A bio-inspired acoustic signal is generated based on the echolocation clicks of entangled toothed whales, using a system with output and input transducers to emit and receive signals, minimizing water echoes, and interpreted by toothed whales to alert them to the danger of nets.
The bio-inspired signal effectively deters toothed whales from nets without causing stress or sonar disturbances, improving deterrence compared to traditional repellent emitters.
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Abstract
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 that can be used in fishing using a fishing net.
[0003] The invention thus has applications, in particular, but not exclusively, in artisanal or industrial net fishing. Prior art and its drawbacks
[0004] Accidental catches in fisheries using one or more nets are the leading direct cause of marine mammal mortality worldwide. Most of these events involve pinnipeds and cetaceans.
[0005] One of the methods developed in recent decades to try to prevent the accidental capture of cetaceans, in particular odontocetes (i.e. toothed cetaceans with sonar) such as dolphins and porpoises, is the use of acoustic repellent emitters (called "pingers" in English), which are attached to fishing nets.
[0006] More specifically, repellent transmitters emit acoustic signals designed to repel toothed whales from nets. These devices use relatively energetic, high-frequency signals within the range of the animals' hearing sensitivity. However, the effectiveness of repellent transmitters varies depending on several factors, such as the species, the fishing gear used (e.g., different types of nets), and the geographical area. Furthermore, behavioral studies have reported negative effects on certain dolphin species, such as a decrease in the number of signals associated with echolocation (i.e., signals that allow them to locate objects in their environment) and a decrease in the number of vocalization signals (i.e., signals that allow communication between individuals), suggesting a reduced ability to detect a net and a higher probability of being caught.
[0007] Finally, if certain repellent emitters are widely deployed in space (i.e. by many fishing vessels and / or installed on large lengths of nets), they could create exclusion zones from animal habitat due to noise pollution.
[0008] It is therefore necessary to develop new, more efficient acoustic devices, without undesirable effects, in order to limit the accidental capture of toothed whales, e.g. such as dolphins. Description of the invention
[0009] In one embodiment of the invention, a method for generating a bio-inspired signal is proposed. According to such a method, an emitting device implementing an output transducer performs:
[0010] - an emission, by the output transducer, of an acoustic signal, called a signal incident, function of a recording of an echolocation click emitted by an odontocete-type animal in a natural environment, the incident signal being emitted towards 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 to limit the accidental capture of marine mammals of the odontocete type (i.e. toothed cetaceans equipped with sonar).
[0015] To achieve this, it is proposed, contrary to the signals used in known repellent emitters, 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 that caused the echolocation click or not).
[0016] Indeed, the sonar of toothed whales is very efficient and allows the animal to obtain precise information about the nature of the object that generated the return signal, e.g., the thickness of the skin of the dead animal entangled in the net, the material it is made of, etc. The return echo of an echolocation click can be interpreted by any individual within a given toothed whale species. Thus, a toothed whale of the same species as the toothed whale that generated the echolocation click used can interpret the bio-inspired signal generated according to the present invention and obtain information about the presence of a net nearby, e.g., a fishing net, and the associated danger of death. The toothed whale 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 diffused from, or near, such a net.The effectiveness of repelling odontocetes is thus improved compared to known repellent emitter techniques via the information contained in the bio-inspired signal which does not. does not generate distancing behavior with stress or sonar disturbance of the odontocete.
[0017] In certain embodiments, the emission of the incident signal includes:
[0018] - a memory readout 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 based 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 supplied to the output transducer delivering the incident signal.
[0023] In some embodiments, the output transducer is an omnidirectional spherical piezoelectric output transducer.
[0024] In some embodiments, the reception of the return echo includes:
[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 as a function of the return signal analog output delivering digital samples, known as return samples; and
[0027] - a writing in memory of final digital samples functions of return samples.
[0028] The bio-inspired signal is a function of the final digital samples.
[0029] In some embodiments, the reception of the return echo includes:
[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 some embodiments, the net containing at least one dead toothed whale 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 toothed whale is less than a first distance between, on the one hand, the output transducer and, on the other hand, the water surface; 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 bottom of the water.
[0035] In certain embodiments:
[0036] - a distance, called the reception distance, between, on the one hand, the input transducer and, on the other hand, the net or the dead toothed whale is less than one-third of the distance between, on the one hand, the inlet transducer and, on the other hand, the water surface; and / or
[0037] - the reception distance is less than one-fourth of the distance between, on the one hand, the input transducer and, on the other hand, the bottom of the water.
[0038] Thus, the rebound effects related to the water surface and the bottom of the water, 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 related to the water surface and the bottom of the water, and therefore the parasitic echoes in the return signal.
[0045] The invention also relates to the use of a bio-inspired signal generated by implementing the generation process as described above (according to any one of the aforementioned embodiments) to keep 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 transmitting device implementing an output transducer, the transmitting device being configured to perform:
[0047] - an emission, by the output transducer, of an acoustic signal, called an acoustic signal incident, function of an echolocation click emitted by an odontocete-type animal in a natural environment, the incident signal being emitted towards a net containing at least one dead odontocete entangled inside.
[0048] The system further includes 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 objects, features and advantages of the invention will become more apparent from the following description, given by way of simple illustrative, and not limiting, example, in relation to the following figure:
[0052] [Fig.1] represents a bio-inspired signal generation system, the system comprising a transmitting device and a receiving device configured to implement the generation process of [Fig.2] according to an embodiment of the invention;
[0053] [Fig. aa] represents an example of the structure of the emission device of the system of the [Fig. l] according to an embodiment of the invention;
[0054] [Fig. 1b] represents an example of the structure of the receiving device of the system of [Fig.1] according to an embodiment of the invention;
[0055] [Fig.2] represents the steps of a process 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 process of the [Fig.2] according to an embodiment of the invention;
[0057] [Fig.2b] represents steps of the reception step of the process for generating [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 process 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.1] a system 100 for generating a bio-inspired signal according to an embodiment of the invention.
[0062] More particularly, the system 100 includes an emission device 100e configured to generate and emit an acoustic signal, called incident signal, based on a recording of an echolocation click emitted by an odontocete-type animal in its natural environment.
[0063] To this end, the transmitting device 100e comprises a device lOOel for generating an analog click signal and an output transducer 100e2 that delivers the incident signal from the analog click signal. For example, the device lOOel for generating the analog click signal comprises ([Fig. 1a]) a random access memory 100el3 (for example, RAM), a processing unit 100el2 equipped, for example, with a processor, and driven by a computer program stored in a read-only memory lOOel1 (for example, ROM or a hard drive). At 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 lOOel 1 stores, for example, digital samples of the echolocation click recording. Such recordings are, for example These echolocation clicks are available for some species in online databases, as supplementary material in online 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 toothed whale that produced the echolocation click. The bandwidth of such an echolocation click depends on the toothed whale in question. For example, for some species the echolocation click spans a narrow frequency band, e.g., the band extending from 120 kHz to 140 kHz for some porpoises. Generally, these are frequencies within the ultrasonic range.
[0065] Returning to [Fig. 1a], a digital-to-analog converter 100el4 (or DAC) converts samples based on the echolocation click recording into an analog signal so as to deliver the analog click signal supplied to the output transducer 100e2. In some embodiments, the device 100el4 includes an amplifier to amplify 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 100e emission device is more particularly configured to carry out certain steps of the process of 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]).
[0067] This [Fig. 1a] illustrates only one particular way, among several possible ways, of implementing the generation device so that it performs all or part of the steps of the generation process 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 interchangeably on a reprogrammable computing machine (a PC, 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 includes 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 readable partially or totally by a computer or a processor.
[0069] Returning to [Fig. 1], the incident signal is emitted towards a net 110, e.g. a fishing net, containing one (or more) dead toothed whale 120 entangled inside. Furthermore, the system 100 includes a receiving device 100r (e.g. a digital hydrophone) configured to receive and process a return signal corresponding to the reflection (i.e. 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 this end, the receiving device lOOr comprises, for example, an input transducer 100r2 (or hydrophone) delivering an analog return signal from the return signal and a processing device lOOrl for the analog return signal. For example, the processing device lOOrl comprises ([Fig.lb]) a random access memory 100rl3 (for example, RAM), a processing unit lOOrl2 equipped, for example, with a processor, and driven by a computer program stored in a read-only memory lOOrl1 (for example, ROM or a hard drive). At 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-to-digital converter 100rl4 (or ADC) converts the analog return signal and delivers digital samples, called return samples. Final digital samples, functions of the return samples, are written to RAM 100rl3. For example, filtering and / or amplification 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 is more particularly configured to carry out certain steps of the process of 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. 1b] illustrates only one particular way, among several possible ways, of implementing the processing device lOOrl so that it performs all or part of the steps in the process of 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]). For example, some of these steps can be performed interchangeably on a reprogrammable computing machine (a PC, 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 includes 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 readable partially or totally by a computer or a processor.
[0075] Returning to [Fig.1], in order to implement the process 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 seawater, 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 certain embodiments, the output transducer 100e2 and the input transducer 100r2 are positioned 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 the emission distance, between, on the one hand, the transducer 100e2 of exit and, on the other hand, the net 110 or the dead toothed whale 120 is less than a first distance between, on the one hand, the exit transducer 100e2 and, on the other hand, the water surface 130; and / or
[0079] - that the emission distance is less than a second distance between, on the one hand, the transducer 100e2 output and, on the other hand, the bottom 140 of the water.
[0080] Furthermore, the input transducer 100r2 is configured to:
[0081] - that a distance, called the reception distance, between, on the one hand, the transducer 100r2 entry and, on the other hand, the net 110 or the dead toothed whale 120 is less than a third distance between, on the one hand, the entry transducer 100r2 and, on the other hand, the water surface 130; and / or
[0082] - that the reception distance is less than one-fourth of the distance between, on the one hand, the 100r2 input transducer and, on the other hand, the 140 water bottom.
[0083] Thus, the rebound effects related 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 spurious echoes in the return signal.
[0091] However, in other implementations, the output transducer 100e2 and the input transducer 100r2 are arranged in other configurations with respect to the water surface 130 and the water bottom 140.
[0092] In certain implementations, the output transducer 100e2 and the input transducer 100r2 are located remotely from the generation device lOOel and the processing device lOOrl, respectively. For example, the output transducer 100e2 is electrically connected to the generation device 100e1 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 and the input transducer 100r2 are immersed to implement the process 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]). Conversely, the lOOel generation device and the lOOrl treatment device remain outside the water in such cases (e.g.The lOOel generation device and the lOOrl processing device 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 specifically, during a step E200 performed by the emitting device 100e, the output transducer 100e2 emits the incident signal based on a recording of an echolocation click emitted by a toothed whale in its natural environment. As described above, the incident signal is emitted in the direction of the net 110 containing one (or more) dead toothed whales 120 entangled inside.
[0095] During a step E210 executed by the receiving device lOOr, 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. Thus, the bio-inspired signal generated by implementing the present generation method (according to any of the embodiments and / or variants described in relation to [Fig. 2], [Fig. 2a], and [Fig. 2b]) includes information indicating the presence of one (or more) dead toothed whales (120) in the vicinity of a net. Furthermore, the bio-inspired signal can be interpreted by a toothed whale of the same species as the one that triggered the echolocation click. The bio-inspired signal can therefore be used to alert a toothed whale of that same species to a nearby danger and thus drive it away, e.g., from a fishing net. To this end, the bio-inspired signal is, for example, emitted by a tag placed on the net.Furthermore, it seems more consistent to use such a bio-inspired signal if the dead toothed whale (or whales) used to generate the signal is of the same species as the one that triggered the echolocation click. Indeed, in this case, the information contained in the bio-inspired signal is all the more relevant to the toothed whale of that species. However, this approach is not necessary, and one (or more) dead toothed whales of a given species (or several types) can be used even if the species in question is not the same as that of the toothed whale that triggered the echolocation click.
[0097] In the embodiment of [Fig. 2a], step E200 comprises:
[0098] - a step E200a in which the emitting device 100e performs a reading from memory 100el3 of digital samples of the echolocation click recording;
[0099] - a step E200b in which the emitting device 100e performs a conversion digital analog of samples function of the digital samples of the echolocation click recording delivering the analog click signal; and
[0100] - a step E200c in which the transmitting device 100e performs a amplification of a signal based 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 can be considered in order to generate the incident signal, e.g. a shaping adapted to the propagation channel, a scaling, an insertion of a preamble so as to facilitate the 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 performs a capture of the return signal by the input transducer 100r2 delivering the analog return signal;
[0105] - a step E210b in which the receiving device performs 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 lOOr performs 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 to obtain the final digital samples. In such cases, step E210 includes, 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 can be considered in order to generate the final digital samples, e.g. 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 its natural environment. [Fig. 4] represents the bio-inspired signal generated by implementing the process of generating [Fig. 2] from the echolocation click of [Fig. 3]. More specifically, in the present case, the process was implemented in the open sea at a depth of twenty meters, in calm seas at slack tide. More specifically, the net 110, containing a dead dolphin 120 (here a short-beaked common dolphin previously found stranded on a beach), and the output transducer 100e2 and the input transducer 100r2, were suspended on the port and starboard sides of a boat. The net 110 was thus positioned approximately three meters from the transducers 100e2 and 100r. A 110 nylon trammel net with a mesh size of two hundred and twenty millimeters was used.The dimensions of the 110 net were approximately four meters long by two meters high. The 110 net was weighted at three points (ends and middle) with lead and chains suspended by ropes three meters below the net to dissociate the acoustic signature of the chains and isolate them from that of the 110 net during post-processing of the return signals. The resulting bio-inspired signal ([Fig. 4]) can be used to deter common dolphins, preferably via the emission of the signal e.g. by one (or more) acoustic beacons submerged along the 110 net.
Claims
Demands
1. Method for generating a bio-inspired signal, characterized in that an emitting device (100e) implementing an output transducer (100e2) performs: - an emission (E200), by the output transducer, of an acoustic signal, called the incident signal, a function of a recording of an echolocation click emitted by an animal of the odontocete type in the natural environment, the incident signal being emitted towards a net (110) comprising at least one dead odontocete (120) entangled inside, and in that a receiving device (100r) implementing an input transducer (100r2) performs: - 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. A method according to claim 1, wherein the incident signal emission comprises: - a memory read (E200a) of digital samples of the echolocation click recording; - a digital-to-analog conversion (E200b) of samples based on the digital samples of the echolocation click recording delivering an analog click signal; and - an amplification (E200c) of a signal based on the analog click signal delivering an amplified signal, the incident signal being a function of the amplified signal.
3. Method according to claim 2, wherein the amplified signal is supplied to the output transducer delivering 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. A method according to any one of claims 1 to 4, wherein the return echo reception comprises: - a capture (E210a) of the return signal by the input transducer delivering an analog return signal; - an analog-to-digital conversion (E210b) of a function signal of the analog return signal delivering digital samples, called return samples; and - a writing (E210c) in memory of final digital samples functions of the return samples, the bio-inspired signal being a function of the final digital samples.
6. A method according to claim 5, wherein the return echo reception comprises: - filtering the return samples delivering filtered digital samples; and - amplifying the filtered digital samples delivering the final digital samples.
7. A method according to any one of claims 1 to 6, wherein the net comprising at least one dead toothed whale is disposed of in the open sea or in a basin filled with water, and wherein: - a distance, called the emission distance, between, on the one hand, the exit transducer and, on the other hand, the net or the dead toothed whale is less than a first distance between, on the one hand, the exit 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 exit transducer and, on the other hand, the bottom (140) of the water.
8. A method according to any one of claims 1 to 7, wherein: - a distance, called the reception distance, between, on the one hand, the inlet transducer and, on the other hand, the net or the dead toothed whale is less than a third distance between, on the one hand, the inlet 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 inlet transducer and, on the other hand, the bottom of the water.
9. A method according to claim 8, insofar as it depends on claim 7, wherein: - 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 implementation of the method according to any one of claims 1 to 9 to keep animals of said odontocete type away from a net.
11. Bio-inspired signal generation system, characterized in that it comprises a transmitting device (100e) implementing an output transducer (100e2), the transmitting device being configured to perform: - an emission (E200), by the output transducer, of an acoustic signal, called the incident signal, a function of an echolocation click emitted by an animal of the odontocete type in its natural environment, the incident signal being emitted towards a net (110) containing at least one dead odontocete (120) entangled inside, and in that it comprises a receiving device (lOOr) implementing an input transducer (100r2), the receiving device being configured to perform: - 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.