Sonar Communication In Fish

Introduction

Animal behavioral includes communication. Animals communicate with themselves and other animals, (http://en.wikipedia.org/wiki/Animal_communication, 2007a). Communication in animals may be visual, sonar or chemical (pheromonal). Sonar communication in fish is particularly important with increasing water depth and decreasing light. Furthermore, sonar communication is best underwater considering that sound attenuates little in water and is directional, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, unknown).

Some fish use sonar communication to communicate both intra- and interspecies. However not all fish sonar communication is audible to humans. Most of the fish sonar communication frequencies are lower than the audio range of humans underwater. Humanly audible sonar communication includes granting by grinding flat Grunt teeth. Some fish when startled or cornered make very loud "booms" (large Jewfish, Nassau and Black Groupers). Others use sonar communication behaviour during courtship. Jewfish use the same very loud "booms" while male Damselfish (reef fish) :chirp" to attract females, (Green Reef , (unknown), Fish Communication, http://ambergriscaye.com/reefbriefs/briefs78.html, accessed 30th September, 2007). Yet other male fish display defensive complex sonar communication behaviour when defending territories, (Damselfish (a reef fish)). "... two males are often seen facing off and emitting a series of combative pops. ", (http://ambergriscaye.com/reefbriefs/briefs78.html, unknown). ooms of the jewfish, the male damselfish produce chirps to attract females.
Reef Brief is a weekly column published in the San Pedro Sun
So, if fish can talk, how do other fish hear these noises if they don't look like they have ears? Fish actually do have ears but they aren't as easily apparent as humans because there is not an outer ear structure. They do have an elaborate inner ear system that allows them to hear. Located next to the brain is a series of interconnected fluid-filled canals. IN these canals is a calcium carbonate ear stone (referred to as the monolith) that is embedded in a nest of hair like sensory cells. It is with this system of canals and monoliths that enables fish to perceive sound.

 

1. http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, (unknown) regards sound as the ideal way for animals to communicate in the ocean since sound attenuates little in the ocean, is directional, and very useful where sunlight does not reach.
2. Animals typically communicate between each other or in networks involving a signaller and more than one receiver. This concept derives from the active space of signals and social spacing of conspecific and heterospecific receivers, (reference???). Animal communication behaviour affects current or future behaviour of other animals. Animal communication and the understanding of the animal world in general is a rapidly growing field. So far, many prior understandings related to diverse fields such as personal symbolic name use, emotions, culture and learning, and even sexual contact have been revolutionised, (http://en.wikipedia.org/wiki/Animal_communication, 2007).
3. Zoosemiotics is the study of animal communication,(http://en.wikipedia.org/wiki/Animal_communication, 2007).

• Ambient noise in underwater acoustics may be due to transient sound sources. Some of these transient sound sources may be due to biological activity from biological sources including cetaceans (especially blue, fin and sperm whales) together with some fish, and snapping shrimp, (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007).

 

METHODOLOGY

• Not much print media was use in collecting information for this report. Most of the information was digital/electronic media from specific sources. The digital media sources that were used in this report include peer reviewed journals, organisational and institutional published information. This greatly limited the information to be used for the report.

RESULTS

It was found that fishes like most animals, communicate with others including their neighbours.

DISCUSSION

University of South Florida: College of Marine Science, (unknown), Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 20th September 2007.

Sound is an ideal way for animals to communicate in the ocean.  Sound attenuates little in the ocean, is directional, and is very useful where there is no light.

Many fishes have evolved the ability to produce sounds by drumming the swimbladder with specialized muscles or bones.  While many fishes are known to produce sound, most have not been studied.

Sound-producing fishes

Gulf Toadfish (Opsanus beta): Gulf toadfish males have specialized swimbladder muscles that are used to produce the sound known as the 'Boatwhistle.  There are 69 species of toadfishes, and the sounds of only five species are known.

Coral Reef Toadfish (Sanopus astrifer):  This toadfish produces a series of 'Boatwhistle calls in a bout.

Gafftopsail Catfish (Bagre marinus): Sea catfish are mouth-brooders that produce several types of sounds. 

Spotted Seatrout (Cynoscion nebulosus):  Spotted seatrout produce a double-pulsed sound along with a moan-like sound.

Silver Perch (Bairdiella chrysura): Silver perch produce a relatively high-frequency staccato sound.  This recording has the sounds of both silver perch and spotted seatrout, recorded in Pine Island Sound, FL. 
Aggregation of silver perch: So many fish can be calling in an aggregation that individual calls are no longer distinguishable (and it may get so loud that you can hear the sound in air).

Cusk eel (Ophidion marginatum):  The cusk eel has a unique sound production mechanism that involves drumming the swimbladder with a modified vertebrae.  There are 209 species of cusk eels.  This is the only cusk-eel sound that has been identified to the species level.

Domino damselfish (Dascyllus albisella): Damselfish produce a sound while performing a visual swimiming display known as the signal jump.    The sound production mechanism is not known.

Dolphins

Echolocation: Dolphin echolocation clicks are very short duration

Signature Whistles: These signature whistles were recorded at about 1 a.m. in Pine Island Sound, FL.  The sound of silver perch can be heard in the background.

Other sounds

Snapping Shrimp: Snapping shrimp are the largest source of sound in the coastal ocean.  They produce very loud broad-band sounds by snapping their claws and cavitating water.

Boat Noise: Boats are the largest source of non-natural sound in the oceans.  This is the sound of a small motorboat in New Pass, Sarasota.

Ecology of Sound Production

Since many fish sounds are associated with reproduction, they can be used a measure of the time and place of spawning.  We are using passive acoustics to identify spawning periodicity for several species in Sarasota Bay and Charlotte Harbor.

It appears the dolphins may home in on sound producing fishes, as several species including catfish, toadfish, and cusk eels are commonly consumed prey.  Dolphin whistles have been shown to suppress the chorusing of some species.  We are investigating the ability of fishes to detect dolphin sounds and whether dolphins passively locate on sound-producing fishes.

__________________________ 

Background

The ocean is not as silent and tranquil as clarified by hydrophonic noise. Some of this noise is from some fish. The most hearing sensitive fish (soldier fish or Pseudolabrus miles) have a threshold of 0.32 mPa (50 dB re 1 μPa) at 1.3 kHz.[36] , (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007).

Fish use unusual mechanisms to make and hear secret whispers, grunts and thumps to attract mates and ward off enermies, seahorses create clicks by tossing their heads. They snap the rear edge of their skulls against their star-shaped bony crests. The seahorse clicks are brief and last between five to twenty milliseconds, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Of the more than 25,000 living fish species today, at least 1,000 of them make sounds. They usea diversity of means by which they make and listen to sounds. The known ones are considered only a handful we know well so far, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

A group of fifty fish species within the one hundred and twenty-six species Butterflyfishes family are the only fish known thus far to couple their swim bladders. They use these organs to improve hearing, with their body's lateral lines (motion detecting organs running along their sides). This is a human equivalent of hearing sounds by wiring ears together with the little hairs on the skin. The butterflyfish emit several types of sounds only ten to one hundred and fifty milliseconds long using tail slaps, fin flicks, fin spine extensions, grunts and jumps. The total power in a single sound is miniscule compared to the loud and long sounds the toadfish and midshipman fish can make, which can last for seconds or minutes and can be heard ten to twenty feet away, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

The butterflyfish may have a swim bladder coupled to their lateral line due to their lack of a way to make loud sounds. They can only generate weak signals. This may be supported by that they swim very close together to listen to their "whispers", , (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Toadfish also communicate with their fish bladders by radidly, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Pearlfish that live within living sea stars or tubular creatures unlike other fish like toadfish, communicate with their swim bladders by rapidly twitching it back and forth with muscles, the pearlfish instead use a much slower muscle that generates strong, low frequency sounds which pearlfish may use to speak with others, advertising their presence even from inside their homes. The pearlfish swim bladder is akin to a bongo drum. It vibrates its skin between four to twenty times per second. This is a highly novel system, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

The study of fish sounds may be the gateway to understanding the evolution of communication and hearing, as well as related behaviours like finding mates or defending territories. An example is the whispering butterflyfish that has evolved pairing behaviour, are social and affiliate with one another a lot, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

As of 2006, the purposes of some fish sounds were still remain mysteries, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Effects of America navy sonar exercises

American navy sonar exercises may cause fish to avoid the area of Onslow Bay (rich grounds for commercial and recreational fishermen). Navy sonar may mask fish noises as made as part of their reproductive process and finding prey. This sonar may mask sounds and disrupt fish communication thus driving fish off, (Rawlins 2006).

That we cannot normally hear much underwater while diving is a deceptive view, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Water transmits sounds better that the air, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Since light penetrates just three hundred metres below the water level, depths below this lie total darkness. In the absence of light, inhabitants of the dark depths communicate via sound, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Sound may be used in echolocation to detect the relief of the bottom as in the Abyssal fish, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Non-fish dark depth inhabitants include Cetaceans (whales and dolphins). These Cetaceans use ultrasound echolocation by emitting 150 kHz that propagate as far as three kilometres. This sound cannot be normally heard by humans. Instead, such sounds can be detected underwater with by ultra-sensitive submarine microphones. These microphones can record, sea water rustles, cracks, gasps, gnashes, bangs, sizzles, drumming sounds, ship whistles, croaks, snores, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Whales can be heard up to eighty kilometres away, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Humpback whales can sing at intervals of 20 minutes for hours, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Fishes may gnash their front teeth to emit sounds. Such is common with Sea Breams (Sparidae), pufferfishes (Tetraodontidae), porcupinefishes (Diodontidae), sunfishes (Molidae); mackerels (Scombridae) that use their pharyngeal teeth. Fishes may also rub their spines to emit sounds. Such fish include Triggerfishes (Balistes), sticklebacks (Gasterosteus), and surgeonfishes (Acanthurus), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Other fish like Clownfishes may use their jawbones to emit clacking sounds. Yet other fishes use muscles on teh walls of their swim bladders to produce vibrations by their contractions. These fishes emit chirp -like sounds. Such fishes include like in gurnards (Trigla), dories (Zeus), toadfishes (Batrachoididae), shark catfishes (Pangasiidae) or armored catfishes (Callichthyidae), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Fish Calls

Fish calls may have social meanings as in herrings, "gathering", "danger", or "change direction". The calls may also be territorial as in clownfishes (Amphiprion). In addition, some fishes may make drumming-like calls to chase away rival males during the mating season. Such fishes include the Croaker males (Sciaena). Similar drummings are emitted by the toadfishes (Opsanus), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Yet other fishes may scare off predators with grumbling calls. These include the Gurnards, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Furthermore, the Pisara (Moenkhausia) produces elephant-like roars, while curbinatas (Plagioscion), produce shots-like sounds, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Seahorses (Hippocampus) emit mating calls, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Communication:
Senses play an important part in fish communication.  Visual communication is important to most fish.  Body movements, postures, colors and color patterns are the primary means of visual communication.  Sound is also used for communication.   Sounds are produced by grinding teeth, flexing or contracting muscles and vibrating the swim bladder.  Fish also communicate by releasing chemicals called pheromones.  These are chemical signals produced by an animal that, when released, influence the behavior of others of the same species.  The sense of smell is important for this form of communication.(Fish Behavior, http://www.seaworld.org/Aquademics/tetra/all_about_fish3.htm, 1999 Warner-Lambert Company)

REFERENCES

1. Wikipedia, (2007), Animal communication, http://en.wikipedia.org/wiki/Animal_communication, accessed 7th September 2007.
2. Wikipedia, (2007),Underwater acoustics, http://en.wikipedia.org/wiki/Underwater_acoustics, accessed 7th September 2007.
3. Rawlins, W. (2006), Science sees trouble in sonar: But effects are poorly understood, http://www.newsobserver.com/712/story/471041.html, accessed 7th September 2007.
4. LiveSCIENCE, (2006), Talking Fish: Wide Variety of Sounds Discovered, http://www.livescience.com/animals/061227_fish_sounds.html, accessed 7th September 2007.
5. Softpedia, (2007), Do Fish Speak? 

   - Fish are noisier than you would have thought, http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, accessed 7th September 2007.

6. University of South Florida: College of Marine Science, (unknown), Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 20th September 2007.

Introduction

Methodology

Information was derived mainly from a variety of peer-reviewed sources of information including journals and publications from reputable institutions including universities.

Results & Discoussion

Fish communicate mostly at frequencies below those audible to man, (http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, 2003). Fish sounds include "rasping", "squeaking", "grunting", and "squealing", (http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, 2003).

However, instruments may be used to detect all sonar communication in fish. These reveal the diversity of sounds used to cummunicate underwater. These include but are not limited to:

• Granting by grinding flat Grunt teeth.

• Very loud "booms" made by Jewfish, Nassau and Black Groupers when startled or cornered, (http://ambergriscaye.com/reefbriefs/briefs78.html, unknown).

    Uses of Sonar Communication In Fish

Although not all fish use sonar communication, there are many sonar communicating fish. These include Jewfish and Finfish. These fish use sonar communiation for many things including includes courtship and dominance, (http://ambergriscaye.com/reefbriefs/briefs78.html , unknown).

Courtship-related sonar communication includes the very loud "booms" of Jewfish mentioned above. Damselfish (reef fish) on the other hand “chirp” to attract females, (http://ambergriscaye.com/reefbriefs/briefs78.html, unknown).

territorial behaviour in fish includes sonar communication. Damselfish males display defensive complex sonar communication behaviour when defending territories. "... two males are often seen facing off and emitting a series of combative pops.", (http://ambergriscaye.com/reefbriefs/briefs78.html, unknown).

Many fish make sounds when they are caught. Grunts and croakers got their names from this habit, (http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, 2003).

    Methods of Sonar Communication

Fish etransmit sound by a variety of ways.

The sounds may be produced by rubbing together vertebrae extensions, vibrating muscles connected to air bladders (sound amplifiers), grinding teeth and amplifying the due sounds with their mouth cavities, (http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, 2003).

        Anatomy of the Fish Ear

Dissimalr to humans, fish ears do not have much of an outer ear structure. Their inner ear structures are made up of a series of interconnected fluid-filled canals next to the brain. In these canals is a calcium carbonate ear stone (otolith) embedded in a nest of hair like sensory cells. This system of canals and otoliths enable fish to recieve sound, (???).

Finfish (class Osteichthyes) have three pairs of otoliths, sagittae, lapilli, and asterisci. Sagittae are the largest, found just behind the eyes and approximately level with them vertically. The lapilli and asterisci (smallest of the three) are located within the semicircular canals, ().

There are many morphologically distinct otoliths in fishes. It is unusually large in fish that aerial at times like the Flyingfish. They need this possibly for aerial balance when they "fly" in the air. In addition, fish from highly structured habitats (reefs or rocky bottoms) like Snappers, Groupers, Drums and Croakers tend to have larger otoliths than other fishes that swim at high speeds in straight lines in the open ocean such as Tuna, Mackerel and Dolphinfish, (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007b).

Zoosemiotics is the study of animal communication,(http://en.wikipedia.org/wiki/Animal_communication, 2007).

Ambient noise in underwater acoustics may be due to transient sound sources. Some of these transient sound sources may be due to biological activity from biological sources including cetaceans (especially blue, fin and sperm whales) together with some fish, and snapping shrimp, (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007).

METHODOLOGY

Not much print media was use in collecting information for this report. Most of the information was digital/electronic media from specific sources. The digital media sources that were used in this report include peer reviewed journals, organisational and institutional published information. This greatly limited the information to be used for the report.

RESULTS

It was found that fishes like most animals, communicate with others including their neighbours.

DISCUSSION

University of South Florida: College of Marine Science, (unknown), Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 20th September 2007.

Sound is an ideal way for animals to communicate in the ocean. Sound attenuates little in the ocean, is directional, and is very useful where there is no light.

Many fishes have evolved the ability to produce sounds by drumming the swimbladder with specialized muscles or bones. While many fishes are known to produce sound, most have not been studied.

Sound-producing fishes

Gulf Toadfish (Opsanus beta): Gulf toadfish males have specialized swimbladder muscles that are used to produce the sound known as the 'boatwhistle'. There are 69 species of toadfishes, and the sounds of only five species are known.

Coral Reef Toadfish (Sanopus astrifer): This toadfish produces a series of 'boatwhistle' calls in a bout.

Gafftopsail Catfish (Bagre marinus): Sea catfish are mouth-brooders that produce several types of sounds.

Spotted Seatrout (Cynoscion nebulosus): Spotted seatrout produce a double-pulsed sound along with a moan-like sound.

Silver Perch (Bairdiella chrysura): Silver perch produce a relatively high-frequency staccato sound. This recording has the sounds of both silver perch and spotted seatrout, recorded in Pine Island Sound, FL.

Aggregation of silver perch: So many fish can be calling in an aggregation that individual calls are no longer distinguishable (and it may get so loud that you can hear the sound in air).

Cusk eel (Ophidion marginatum): The cusk eel has a unique sound production mechanism that involves drumming the swimbladder with a modified vertebrae. There are 209 species of cusk eels. This is the only cusk-eel sound that has been identified to the species level.

Domino damselfish (Dascyllus albisella): Damselfish produce a sound while performing a visual swimiming display known as the signal jump. The sound production mechanism is not known.

Dolphins

Echolocation: Dolphin echolocation clicks are very short duration

Signature Whistles: These signature whistles were recorded at about 1 a.m. in Pine Island Sound, FL. The sound of silver perch can be heard in the background.

Other sounds

Snapping Shrimp: Snapping shrimp are the largest source of sound in the coastal ocean. They produce very loud broad-band sounds by snapping their claws and cavitating water.

Boat Noise: Boats are the largest source of non-natural sound in the oceans. This is the sound of a small motorboat in New Pass, Sarasota.

Ecology of Sound Production

Since many fish sounds are associated with reproduction, they can be used a measure of the time and place of spawning. We are using passive acoustics to identify spawning periodicity for several species in Sarasota Bay and Charlotte Harbor.

It appears the dolphins may home in on sound producing fishes, as several species including catfish, toadfish, and cusk eels are commonly consumed prey. Dolphin whistles have been shown to suppress the chorusing of some species. We are investigating the ability of fishes to detect dolphin sounds and whether dolphins passively locate on sound-producing fishes.

__________________________

Background

The ocean is not as silent and tranquil as clarified by hydrophonic noise. Some of this noise is from some fish. The most hearing sensitive fish (soldier fish or Pseudolabrus miles) have a threshold of 0.32 mPa (50 dB re 1 μPa) at 1.3 kHz.[36] , (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007).

Fish use unusual mechanisms to make and hear secret whispers, grunts and thumps to attract mates and ward off enermies, seahorses create clicks by tossing their heads. They snap the rear edge of their skulls against their star-shaped bony crests. The seahorse clicks are brief and last between five to twenty milliseconds, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Of the more than 25,000 living fish species today, at least 1,000 of them make sounds. They usea diversity of means by which they make and listen to sounds. The known ones are considered only a handful we know well so far, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

A group of fifty fish species within the one hundred and twenty-six species Butterflyfishes family are the only fish known thus far to couple their swim bladders. They use these organs to improve hearing, with their body's lateral lines (motion detecting organs running along their sides). This is a human equivalent of hearing sounds by wiring ears together with the little hairs on the skin. The butterflyfish emit several types of sounds only ten to one hundred and fifty milliseconds long using tail slaps, fin flicks, fin spine extensions, grunts and jumps. The total power in a single sound is miniscule compared to the loud and long sounds the toadfish and midshipman fish can make, which can last for seconds or minutes and can be heard ten to twenty feet away, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

The butterflyfish may have a swim bladder coupled to their lateral line due to their lack of a way to make loud sounds. They can only generate weak signals. This may be supported by that they swim very close together to listen to their "whispers", , (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Toadfish also communicate with their fish bladders by radidly, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Pearlfish that live within living sea stars or tubular creatures unlike other fish like toadfish, communicate with their swim bladders by rapidly twitching it back and forth with muscles, the pearlfish instead use a much slower muscle that generates strong, low frequency sounds which pearlfish may use to speak with others, advertising their presence even from inside their homes. The pearlfish swim bladder is akin to a bongo drum. It vibrates its skin between four to twenty times per second. This isa higly novel system, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

The study of fish sounds may be the gateway to understanding the evolution of communication and hearing, as well as related behaviours like finding mates or defending territories. An example is the whispering butterflyfish that has evolved pairing behaviour, are social and affiliate with one another a lot, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

As of 2006, the purposes of some fish sounds were still remain mysteries, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Effects of America navy sonar exercises

American navy sonar exercises may cause fish to avoid the area of Onslow Bay (rich grounds for commercial and recreational fishermen). Navy sonar may mask fish noises as made as part of their reproductive process and finding prey. This sonar may mask sounds and disrupt fish communication thus driving fish off, (Rawlins 2006).

That we cannot normally hear much underwater while diving is a deceptive view, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Water transmits sounds better that the air, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Since light penetrates just three hundred metres below the water level, depths below this lie total darkness. In the absence of light, inhabitants of the dark depths communicate via sound, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Sound may be used in echolocation to detect the relief of the bottom as in the Abyssal fish, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Non-fish dark depth inhabitants include Cetaceans (whales and dolphins). These Cetaceans use ultrasound echolocation by emiting 150 kHz that propagate as far as three kilometres. This sound cannot be normally heard by humans. Instead, such sounds can be detected underwater with by ultra-sensitive submarine microphones. These micrphones can record, sea water rustles, cracks, gasps, gnashes, bangs, sizzles, drumming sounds, ship whistles, croaks, snores, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Whales can be heard up to eighty kilometres away, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Humpback whales can sing at intervals of 20 minutes for hours, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Fishes may gnash their front teeth to emit sounds. Such is common with seabreams (Sparidae), pufferfishes (Tetraodontidae), porcupinefishes (Diodontidae), sunfishes (Molidae); mackerels (Scombridae) that use their pharyngeal teeth. Fishes may also rub their spines to emit sounds. Such fish include Triggerfishes (Balistes), sticklebacks (Gasterosteus), and surgeonfishes (Acanthurus), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Other fish like Clownfishes may use their jawbones to emit clacking sounds. Yet other fishes use muscles on teh walls of their swim bladders to produce vibrations by their contractions. These fishes emit chirp -like sounds. Such fishes include like in gurnards (Trigla), dories (Zeus), toadfishes (Batrachoididae), shark catfishes (Pangasiidae) or armored catfishes (Callichthyidae), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Fish Calls

Fish calls may have social meanings as in herrings, "gathering", "danger", or "change direction". The calls may also be territorial as in clownfishes (Amphiprion). In addition, some fishes may make drumming-like calls to chase away rival males during the mating season. Such fishes include the Croaker males (Sciaena). Similar drummings are emitted by the toadfishes (Opsanus), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Yet other fishes may scare off predators with grumbling calls. These include the Gurnards, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Furthermore, the Pisara (Moenkhausia) produces elephant-like roars, while curbinatas (Plagioscion), produce shots-like sounds, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Seahorses (Hippocampus) emit mating calls, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Communication:

Senses play an important part in fish communication. Visual communication is important to most fish. Body movements, postures, colors and color patterns are the primary means of visual communication. Sound is also used for communication. Sounds are produced by grinding teeth, flexing or contracting muscles and vibrating the swim bladder. Fish also communicate by releasing chemicals called pheromones. These are chemical signals produced by an animal that, when released, influence the behavior of others of the same species. The sense of smell is important for this form of communication.(Fish Behavior, http://www.seaworld.org/Aquademics/tetra/all_about_fish3.htm, 1999 Warner-Lambert Company)

SONAR COMMUNICATION IN FISH

Introduction

    Fish Communication

Some fish use sonar communication to communicate both intra- and interspecies. However not all fish sonar communication is audible to humans. Most of the fish sonar communication frequencies are lower than the audio range of humans underwater. Humanly audible sonar communication includes granting by grinding flat Grunt teeth. Some fish when startled or cornered make very loud "booms" (large Jewfish, Nassau and Black Groupers). Others use sonar communication behaviour during courtship. Jewfish use the same very loud "booms" while male Damselfish (reef fish) :chirp" to attract females, (Green Reef , (unknown), Fish Communication, http://ambergriscaye.com/reefbriefs/briefs78.html, accessed 30th September, 2007). Yet other male fish display defensive complex sonar communication behaviour when defending territories, (Damselfish (a reef fish)). "... two males are often seen facing off and emitting a series of combative pops. ", (http://ambergriscaye.com/reefbriefs/briefs78.html, unknown). ooms of the jewfish, the male damselfish produce chirps to attract females.
Reef Brief is a weekly column published in the San Pedro Sun
So, if fish can talk, how do other fish hear these noises if they don't look like they have ears? Fish actually do have ears but they aren't as easily apparent as humans because there is not an outer ear structure. They do have an elaborate inner ear system that allows them to hear. Located next to the brain is a series of interconnected fluid-filled canals. IN these canals is a calcium carbonate ear stone (referred to as the otolith) that is embedded in a nest of hair like sensory cells. It is with this system of canals and otoliths that enables fish to perceive sound.

INTRODUCTION

• http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, (unknown) regards sound as the ideal way for animals to communicate in the ocean since sound attenuates little in the ocean, is directional, and very useful where sunlight does not reach.

• Animals typically communicate between each other or in networks involving a signaller and more than one receiver. This concept derives from the active space of signals and social spacing of conspecific and heterospecific recievers, (reference???). Animal communication behaviour affects current or future behaviour of other animals. Animal communication and the understanding of the animal world in general is a rapidly growing field. So far, many prior understandings related to diverse fields such as personal symbolic name use, emotions, culture and learning, and even sexual contact have been revolutionised, (http://en.wikipedia.org/wiki/Animal_communication, 2007).

• Zoosemiotics is the study of animal communication,(http://en.wikipedia.org/wiki/Animal_communication, 2007).

• Ambient noise in underwater acoustics may be due to transient sound sources. Some of these transient sound sources may be due to biological activity from biological sources including cetaceans (especially blue, fin and sperm whales) together with some fish, and snapping shrimp, (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007).

METHODOLOGY

Not much print media was use in collecting information for this report. Most of the information was digital/electronic media from specific sources. The digital media sources that were used in this report include peer reviewed journals, organisational and institutional published information. This greatly limited the information to be used for the report.

RESULTS

It was found that fishes like most animals, communicate with others including their neighbours.

DISCUSSION

University of South Florida: College of Marine Science, (unknown), Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 20th September 2007.

Sound is an ideal way for animals to communicate in the ocean.  Sound attenuates little in the ocean, is directional, and is very useful where there is no light.

Many fishes have evolved the ability to produce sounds by drumming the swimbladder with specialized muscles or bones.  While many fishes are known to produce sound, most have not been studied.

Sound-producing fishes

Gulf Toadfish (Opsanus beta): Gulf toadfish males have specialized swimbladder muscles that are used to produce the sound known as the 'boatwhistle'.  There are 69 species of toadfishes, and the sounds of only five species are known.

Coral Reef Toadfish (Sanopus astrifer):  This toadfish produces a series of 'boatwhistle' calls in a bout.

Gafftopsail Catfish (Bagre marinus): Sea catfish are mouth-brooders that produce several types of sounds. 

Spotted Seatrout (Cynoscion nebulosus):  Spotted seatrout produce a double-pulsed sound along with a moan-like sound.

Silver Perch (Bairdiella chrysura): Silver perch produce a relatively high-frequency staccato sound.  This recording has the sounds of both silver perch and spotted seatrout, recorded in Pine Island Sound, FL. 
Aggregation of silver perch: So many fish can be calling in an aggregation that individual calls are no longer distinguishable (and it may get so loud that you can hear the sound in air).

Cusk eel (Ophidion marginatum):  The cusk eel has a unique sound production mechanism that involves drumming the swimbladder with a modified vertebrae.  There are 209 species of cusk eels.  This is the only cusk-eel sound that has been identified to the species level.

Domino damselfish (Dascyllus albisella): Damselfish produce a sound while performing a visual swimiming display known as the signal jump.    The sound production mechanism is not known.

Dolphins

Echolocation: Dolphin echolocation clicks are very short duration

Signature Whistles: These signature whistles were recorded at about 1 a.m. in Pine Island Sound, FL.  The sound of silver perch can be heard in the background.

Other sounds

Snapping Shrimp: Snapping shrimp are the largest source of sound in the coastal ocean.  They produce very loud broad-band sounds by snapping their claws and cavitating water.

Boat Noise: Boats are the largest source of non-natural sound in the oceans.  This is the sound of a small motorboat in New Pass, Sarasota.

Ecology of Sound Production

Since many fish sounds are associated with reproduction, they can be used a measure of the time and place of spawning.  We are using passive acoustics to identify spawning periodicity for several species in Sarasota Bay and Charlotte Harbor.

It appears the dolphins may home in on sound producing fishes, as several species including catfish, toadfish, and cusk eels are commonly consumed prey.  Dolphin whistles have been shown to suppress the chorusing of some species.  We are investigating the ability of fishes to detect dolphin sounds and whether dolphins passively locate on sound-producing fishes.

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Background

The ocean is not as silent and tranquil as clarified by hydrophonic noise. Some of this noise is from some fish. The most hearing sensitive fish (soldier fish or Pseudolabrus miles) have a threshold of 0.32 mPa (50 dB re 1 μPa) at 1.3 kHz.[36] , (http://en.wikipedia.org/wiki/Underwater_acoustics, 2007).

Fish use unusual mechanisms to make and hear secret whispers, grunts and thumps to attract mates and ward off enermies, seahorses create clicks by tossing their heads. They snap the rear edge of their skulls against their star-shaped bony crests. The seahorse clicks are brief and last between five to twenty milliseconds, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Of the more than 25,000 living fish species today, at least 1,000 of them make sounds. They usea diversity of means by which they make and listen to sounds. The known ones are considered only a handful we know well so far, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

A group of fifty fish species within the one hundred and twenty-six species Butterflyfishes family are the only fish known thus far to couple their swim bladders. They use these organs to improve hearing, with their body's lateral lines (motion detecting organs running along their sides). This is a human equivalent of hearing sounds by wiring ears together with the little hairs on the skin. The butterflyfish emit several types of sounds only ten to one hundred and fifty milliseconds long using tail slaps, fin flicks, fin spine extensions, grunts and jumps. The total power in a single sound is miniscule compared to the loud and long sounds the toadfish and midshipman fish can make, which can last for seconds or minutes and can be heard ten to twenty feet away, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

The butterflyfish may have a swim bladder coupled to their lateral line due to their lack of a way to make loud sounds. They can only generate weak signals. This may be supported by that they swim very close together to listen to their "whispers", , (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Toadfish also communicate with their fish bladders by radidly, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Pearlfish that live within living sea stars or tubular creatures unlike other fish like toadfish, communicate with their swim bladders by rapidly twitching it back and forth with muscles, the pearlfish instead use a much slower muscle that generates strong, low frequency sounds which pearlfish may use to speak with others, advertising their presence even from inside their homes. The pearlfish swim bladder is akin to a bongo drum. It vibrates its skin between four to twenty times per second. This isa higly novel system, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

The study of fish sounds may be the gateway to understanding the evolution of communication and hearing, as well as related behaviours like finding mates or defending territories. An example is the whispering butterflyfish that has evolved pairing behaviour, are social and affiliate with one another a lot, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

As of 2006, the purposes of some fish sounds were still remain mysteries, (http://www.livescience.com/animals/061227_fish_sounds.html, 2006).

Effects of America navy sonar exercises

American navy sonar exercises may cause fish to avoid the area of Onslow Bay (rich grounds for commercial and recreational fishermen). Navy sonar may mask fish noises as made as part of their reproductive process and finding prey. This sonar may mask sounds and disrupt fish communication thus driving fish off, (Rawlins 2006).

That we cannot normally hear much underwater while diving is a deceptive view, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Water transmits sounds better that the air, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Since light penetrates just three hundred metres below the water level, depths below this lie total darkness. In the absence of light, inhabitants of the dark depths communicate via sound, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Sound may be used in echolocation to detect the relief of the bottom as in the Abyssal fish, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Non-fish dark depth inhabitants include Cetaceans (whales and dolphins). These Cetaceans use ultrasound echolocation by emiting 150 kHz that propagate as far as three kilometres. This sound cannot be normally heard by humans. Instead, such sounds can be detected underwater with by ultra-sensitive submarine microphones. These micrphones can record, sea water rustles, cracks, gasps, gnashes, bangs, sizzles, drumming sounds, ship whistles, croaks, snores, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Whales can be heard up to eighty kilometres away, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Humpback whales can sing at intervals of 20 minutes for hours, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Fishes may gnash their front teeth to emit sounds. Such is common with seabreams (Sparidae), pufferfishes (Tetraodontidae), porcupinefishes (Diodontidae), sunfishes (Molidae); mackerels (Scombridae) that use their pharyngeal teeth. Fishes may also rub their spines to emit sounds. Such fish include Triggerfishes (Balistes), sticklebacks (Gasterosteus), and surgeonfishes (Acanthurus), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Other fish like Clownfishes may use their jawbones to emit clacking sounds. Yet other fishes use muscles on teh walls of their swim bladders to produce vibrations by their contractions. These fishes emit chirp -like sounds. Such fishes include like in gurnards (Trigla), dories (Zeus), toadfishes (Batrachoididae), shark catfishes (Pangasiidae) or armored catfishes (Callichthyidae), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Fish Calls

Fish calls may have social meanings as in herrings, "gathering", "danger", or "change direction". The calls may also be territorial as in clownfishes (Amphiprion). In addition, some fishes may make drumming-like calls to chase away rival males during the mating season. Such fishes include the Croaker males (Sciaena). Similar drummings are emitted by the toadfishes (Opsanus), (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007). Yet other fishes may scare off predators with grumbling calls. These include the Gurnards, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Furthermore, the Pisara (Moenkhausia) produces elephant-like roars, while curbinatas (Plagioscion), produce shots-like sounds, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Seahorses (Hippocampus) emit mating calls, (http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, 2007).

Communication:
Senses play an important part in fish communication.  Visual communication is important to most fish.  Body movements, postures, colors and color patterns are the primary means of visual communication.  Sound is also used for communication.   Sounds are produced by grinding teeth, flexing or contracting muscles and vibrating the swim bladder.  Fish also communicate by releasing chemicals called pheromones.  These are chemical signals produced by an animal that, when released, influence the behavior of others of the same species.  The sense of smell is important for this form of communication.(Fish Behavior, http://www.seaworld.org/Aquademics/tetra/all_about_fish3.htm, 1999 Warner-Lambert Company)

REFERENCES

1. Wikipedia, (2007), Animal communication, http://en.wikipedia.org/wiki/Animal_communication, accessed 7th September 2007.
2. Wikipedia, (2007),Underwater acoustics, http://en.wikipedia.org/wiki/Underwater_acoustics, accessed 7th September 2007.
3. Rawlins, W. (2006), Science sees trouble in sonar: But effects are poorly understood, http://www.newsobserver.com/712/story/471041.html, accessed 7th September 2007.
4. LiveSCIENCE, (2006), Talking Fish: Wide Variety of Sounds Discovered, http://www.livescience.com/animals/061227_fish_sounds.html, accessed 7th September 2007.
5. Softpedia, (2007), Do Fish Speak? - Fish are noisier than you would have thought, http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, accessed 7th September 2007.
6. University of South Florida: College of Marine Science, (unknown), Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 20th September 2007.

Wiley, (2003), Fish Anatomy, http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, accessed 7th September 2007.

Fish do not really have outer ears like humans do. However, they are still capable of hearing. Their inner ears are located within their skulls. Usually, the inner ear bones bones are connected to air bladders. The air bladders are the sounding boards of sonar vibrations from the ears, (http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, 2003).

The lateral-line system, that runs along the length of both sides of the fish’s body recieves low-frequency vibrations. It has better "hearing" sensitivity than human ears. Typically the lateral line is a mucus-filled canal beneath the skin and contacts with the external environment via pores in the skin or scales along the line or in-between them. It is innervated. The lateral-line system has morphologicval variations. It may extend over the fish’s tail, continue onto the head or even branch along the outer bones of their skulls, where it is not outwardly visible. Other than sensing vibrations, the lateral-line system is used to determine the direction of currents of water and the presence of nearby objects. It is also used to determine temperature and to navigate in the dark. Furthermore, it assists schooling fish to keep together and possibly escape predation, (http://media.wiley.com/product_data/excerpt/54/04714499/0471449954.pdf, 2003).

REFERENCES

1. Wikipedia, (2007a), Animal communication, http://en.wikipedia.org/wiki/Animal_communication, accessed 7th September 2007.

2. College of Marine Science: University of South Florida, Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 7th September 2007.

3. Green Reef , (unknown), Fish Communication, http://ambergriscaye.com/reefbriefs/briefs78.html, accessed 30th September, 2007.

4. Wikipedia, (2007b),Underwater acoustics, http://en.wikipedia.org/wiki/Underwater_acoustics, accessed 7th September 2007.

5. Wikipedia,  (2007c), Otolith, http://en.wikipedia.org/wiki/Otolith, accessed 7th September 2007.

6. Rawlins, W. (2006), Science sees trouble in sonar: But effects are poorly understood, http://www.newsobserver.com/712/story/471041.html, accessed 7th September 2007.

7. LiveSCIENCE, (2006), Talking Fish: Wide Variety of Sounds Discovered, http://www.livescience.com/animals/061227_fish_sounds.html, accessed 7th September 2007.

8. Softpedia, (2007), Do Fish Speak? - Fish are noisier than you would have thought, http://news.softpedia.com/news/Do-Fish-Speak-56269.shtml, accessed 7th September 2007.

9. University of South Florida: College of Marine Science, (unknown), Marine Animal Sound Production, http://www.marine.usf.edu/bio/fishlab/fish_sound_production.htm, accessed 20th September 2007.