How do fish communicate?

In this article, we will answer the question “How do fish communicate?” and learn about the communication modalities used by fish. 

We already know a lot about aquatic mammals communication, but what about fish communication?

How do fish communicate?

Fish communicate by producing chirps, grunts, growls, and pops. They can also use vision to communicate through colours, bioluminescence, gesture and posture, or releasing chemicals and hormones in the water, that can be smelled or tasted by other fish.

Acoustics

Fish can communicate by producing sounds. These sounds are usually produced by contracting and vibrating the swim bladder. Studies in captivity recorded many species in isolation. However, in the ocean they also vocalise. Most of the sounds produced by fish are inaudible to human hearing

The acoustic communication modality is used for many reasons in fish. They use it to share information about prey when hunting, about predators, during courtship, breeding and spawning, and to establish their territory. 

Fish also use sounds to navigate in a shoal, swap places while navigating and detect predators and prey. Some fish species build a nest and start producing sounds to attract potential mates.

Most of these sounds are produced by contracting and vibrating the swim bladder. Fish have a strong muscle attached to the swim bladder. This muscle is responsible for sequential contraction and relaxation. These movements make the swim bladder vibrate, thus, producing sounds.

There are also some other ways that fish produce sounds, they are striking and gnashing teeth and bones. Some catfish species move the spines to generate sounds.

Some examples of fish species that produce sound and their motives are:

–       Plainfin midshipman – attract females and protect territory;

–       Oyster Toadfish – courtship calls;

–       Dusky Damselfish – protect the territory from other damselfish and avoid predators;

–       Cod – shoal mates communication.

Human noises can affect fish acoustic communication. The landscape sounds are very important for this communication modality. Human sounds as boat and ship motors, sonars, and explosives, can affect the fish. Some fish become unable to use acoustics as communication because their sounds do not overcome the landscape sounds. Thus, making the fish more vulnerable to predators, difficult hunting and breeding. 

In addition, fish can also be biologically affected by noise pollution. As a result of the stress caused by noise pollution, fish species can develop malformations before hatching and some physiological disorders due to stress.

Visual

The visual communication modality occurs in many forms. From gestures and postures to colours and lights.

Bioluminescence is a mixed modality between visual and chemical. Although the light generation is the result of chemical reactions, the transmitted communication signal is visual, the light. Thus, this modality is classified as visual. 

The bioluminescent fish species have specialised organs called photophores. These organs are usually filled with many bioluminescent bacteria responsible for light production. As the ocean can become very dark in the depths, bioluminescence can assist in many vital activities, such as hunting, mating, and avoiding predators. 

To hunt, fish may use the photophores as baits to lure their prey to swim closer enough to be captured. The light can also avoid predators by warning them. The photophores are also used for individual identifications and communicating with other species.

The colours are the most developed communication modality in fish. It is not rare to find species that can change or alter their body colours. Some fish species use glowing body colours as a warning signal to avoid predators, while others can mimic other species by changing their entire colour pattern. Other species can also use colour during the breeding season, to show there are available for mating.

Some fish species that use colours to communicate are:

–       Lionfish;

–       Groupers;

–       Anglerfish.

Another type of visual communication modality is the use of gesture and posture. Some fish can open their fins and operculum to look larger to their predators, or even for finding potential mates in courtship behaviour. In addition, some species use “dances” to attract mates, as in a ritual. Some males can even use objects or environmental features to build nests to impress females and convince them to breed. Between the species that use display and posture to communicate is possible to highlight the Betta fish and the Guppy.

Chemical

Little is known about the chemical communication of fish, and this is probably because of the aquatic environment that is difficult for us to understand and detect. Some recent studies have shown that fish can use urine to avoid competitors. Thus, urinating can be associated with other aggressive behaviours, as sounds and posture.

In addition to urine, some fish can release pheromones in the water. Pheromones are used for breeding and socializing. Female zebrafish are known to use this communication modality to attract males.

Some fish that use this communication modality are:

–       Zebrafish;

–       Cichlids.

Electrical

Some fish species communicate through electric signals. These signals can also be used for locating prey. Other fish species can use electrical pulses to navigate. Their bodies are covered in electric receptors to receive the signals coming from other animals and to detect the reflex of their own electrical discharge on environmental structures.

Some species that uses electric signals as communication modality are:

–       Electric eels;

–       Elephantnose fish.

Electric eels own very specialised organs for electrical impulses generation and reception. Usually, these specialised organs occupy the majority of the electric eel’s body, around 80% of it. They use electrical discharges to navigate, hunt, defence and communicate. The low, or weak, electric signals are generated in form of short pulses for communicating.

How can humans affect fish communication?

Noise pollution is the name given to the human sounds that disturb an environment. If we consider this type of pollution, underwater is very similar to the world on land. It is not difficult to hear a motorboat or a jet ski while we are underwater with our air-sound specialised ears. Now, can you imagine how the fish hear these artificial human sounds?

Human underwater noise pollution is already known to provoke many issues on aquatic mammals and birds. However, little was known about the effects of noise pollution on fish until recently. Some studies showed that fish species can be extremely affected as a stress response or due to the difficulties in communicating, locating prey and predators, and navigating.

Although human noise can be significantly harmful to many fish species, if used properly human-generated sounds may help reef areas to recover their health and attract inhabitants back. 

Few studies used loudspeakers to reproduce landscape sounds of a healthy reef area in reef areas that need to recover. This landscapes sounds showed that they are capable of attracting fish species back to the area in recovery and accelerated this process. The full recovery occurred quicker than if the area was left to recover naturally. This is because the fish species that were attracted could then assist in the reef reconstruction and full recovery.

Conclusion 

In this article, we answered the question “How do fish communicate?” and learnt more about the communication modalities used by fish

If you have any thoughts or doubts, feel free to drop us in a comment below!

Frequently Asked Questions (FAQs): How do fish communicate?

Do fish communicate with sound?

Yes, fish also use sound as a communication modality. Some studies revealed that fish produces chirps, grunts, growls and pops to communicate with each other.

Do fish recognize each other?

Yes. Researchers have found that fish recognize each other by hearing memory. In addition, fish are known to have memories about interactions from the past and can show affection.

Can fish hear you? 

Yes, fish are able to hear the human voice. However, they can also feel the water vibrations when propagating sound. Although fish can hear the human voice, no proof has shown they can assimilate the content, such as recognizing their names.

Do fish have personalities?

Yes, fish have personalities. Studies have shown that fish can be shy, taking fewer risks and avoiding new situations, while others can be bold, keener to take risks and explore.

Do fish recognize they are siblings?

Once fish can recognize other fish, they are able to tell about other fish sibling relationships. However, they are probably not able to identify themselves. 

Can fish respond to their names?

No, fish cannot respond to their names. Although fish uses the hearing sense, they are not capable of assimilating their names. However, they can recognize your face and assimilate your presence with food, etc.

Are fish affected by noise pollution?

Yes, fish are very affected by noise pollution. Moderate noise levels are known to cause temporary damage to the fish hearing sense. This damage can last for weeks before the fish fully recover. The stress response is also known to cause many physiological issues and reduce fish life span.

Are fish sensitive to light?

Yes, fish sight is quite similar to mammals and birds. They normally have rod and cone cells in their retinas. Thus, most of them are capable of detecting different colours and shades (light and shadow). Some fish species can even see ultraviolet light. 

How many fish species produce sound?

Currently, in the entire world is known that around 800 fish species can produce sounds during a variety of behaviours. These behaviour include hunting, breeding, and avoiding predators, for example.

References 

Kalam, T. 2020. How Do Fish Communicate With Each Other?. https://www.scienceabc.com/nature/animals/how-do-fish-communicate-with-each-other.html

Marine fish communication. https://dosits.org/animals/use-of-sound/marine-fish-communication/

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