Editing Bioacoustics (section)

==Methods==
[[Image:Underwater-microphone hg.jpg|thumb|80px|right|Hydrophone]]
Listening is still one of the main methods used in bioacoustical research. Little is known about neurophysiological processes that play a role in production, detection and interpretation of sounds in animals, so [[ethology|animal behaviour]] and the signals themselves are used for gaining insight into these processes. 

Bioacoustics has also helped to pave the way for new emerging methods such as ecoacoustics (or [[acoustic ecology]]),<ref>{{Citation |last1=Farina |first1=Almo |title=Ecoacoustics: A New Science |date=2017 |work=Ecoacoustics |pages=1–11 |url=https://onlinelibrary.wiley.com/doi/10.1002/9781119230724.ch1 |access-date=2025-01-21 |publisher=John Wiley & Sons, Ltd |language=en |doi=10.1002/9781119230724.ch1 |isbn=978-1-119-23072-4 |last2=Gage |first2=Stuart H.|url-access=subscription }}</ref> an interdisciplinary field of research that studies the sounds produced by ecosystems, including biological, geophysical and anthropogenic sources. It examines how these sounds interact with the environment, providing insights into biodiversity, habitat health and ecological processes. By analysing soundscapes, ecoacoustics helps monitor environmental changes, assess conservation efforts and detect human impacts on natural systems.

===Acoustic signals===
[[Image:Akhumps_128_016_0_500c.png|thumb|200px|left|[[Spectrogram]] (above) and [[oscillogram]] (below) of the [[humpback whale]]'s calls]]
An experienced observer can use animal sounds to recognize a "singing" animal [[species]], its location and condition in nature. Investigation of animal sounds also includes signal recording with electronic recording equipment. Due to the wide range of signal properties and media they propagate through, specialized equipment may be required instead of the usual [[microphone]], such as a [[hydrophone]] (for underwater sounds), detectors of [[ultrasound]] (very high-[[frequency]] sounds) or [[infrasound]] (very low-frequency sounds), or a [[laser Doppler vibrometer|laser vibrometer]] (substrate-borne vibrational signals). [[Computer]]s are used for storing and analysis of recorded sounds. Specialized sound-editing [[software]] is used for describing and sorting signals according to their [[amplitude|intensity]], [[frequency]], duration and other parameters.

Animal sound collections, managed by [[museum of natural history|museums of natural history]] and other institutions, are an important tool for systematic investigation of signals. Many effective automated methods involving signal processing, data mining, machine learning and artificial intelligence<ref>{{Cite magazine |last=Rodrigues |first=Meghie |date=13 January 2024 |title=The song of a missing bird may help scientists find it |url=<!-- citation from paper magazine --> |department=The Science Life |magazine=[[Science News]] |page=4}}</ref> techniques have been developed to detect and classify the bioacoustic signals.<ref>M. Pourhomayoun, P. Dugan, M. Popescu, and C. Clark, “Bioacoustic Signal Classification Based on Continuous Region Features, Grid Masking Features and Artificial Neural Network,” International Conference on Machine Learning (ICML), 2013.</ref>

===Sound production, detection, and use in animals===
[[Scientist]]s in the field of bioacoustics are interested in anatomy and neurophysiology of [[organ (anatomy)|organs]] involved in sound production and detection, including their shape, [[muscle]] action, and activity of [[neuronal network]]s involved. Of special interest is coding of signals with [[action potential]]s in the latter.

But since the methods used for neurophysiological research are still fairly complex and understanding of relevant processes is incomplete, more trivial methods are also used. Especially useful is observation of behavioural responses to acoustic signals. One such response is [[phonotaxis]] – directional movement towards the signal source. By observing response to well defined signals in a controlled environment, we can gain insight into signal function, [[Stimulus (physiology)|sensitivity]] of the hearing apparatus, [[noise]] filtering capability, etc.

===Biomass estimation===
{{main|Hydroacoustics}}
Biomass estimation is a method of detecting and quantifying [[fish]] and other marine organisms using [[sonar]] technology.<ref name="SimmondsMacLennan"/> As the sound pulse travels through water it encounters objects that are of different density than the surrounding medium, such as fish, that reflect sound back toward the sound source. These echoes provide information on fish size, location, and [[abundance (ecology)|abundance]]. The basic components of the scientific [[echo sounder]] hardware function is to transmit the sound, receive, filter and amplify, record, and analyze the echoes. While there are many manufacturers of commercially available "fish-finders," quantitative analysis requires that measurements be made with [[calibration|calibrated]] echo sounder equipment, having high [[signal-to-noise ratio]]s.