Lobsters make a noise like squeaky rubber with their antennae that can be heard almost TWO MILES away underwater ‘to ward of predators’
- Researchers assessed more than 1,000 rasps produced by 24 lobsters
- The noises are made when it rubs its antennae against a protrusion under its eye
- Researchers speculate that large lobsters could be heard 1.8 (3km) away
- Believed that these noises are for communication or deterring predators
A species of European lobster makes a unique noise which can be detected underwater almost two miles away, a new study claims.
The sound is created when the European spiny lobster scrapes the fleshy end of their antenna against file-like plates covered in microscopic ridges below its eye.
The exact purpose of these long-travelling rasps is unknown but scientists believe it is to either communicate with other lobsters or deter predators.
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A species of European lobster makes a unique noise which can be detected underwater almost two miles away. The noise is created when the European spiny lobster rubs part of its antennae against a protrusion under its eye
Pictured, a close view of a juvenile spiny lobster laying on the hand of a scuba diver. The authors found that only large individuals could be recorded at 100m distance, whereas intermediate, small and very small individuals could not be recorded at distances above 50, 20 and 10 m, respectively
Twenty-four lobsters were tracked in the Bay of Saint Anne du Portzic, France.
Corresponding author Youenn Jezequel, a doctoral student in marine biology at the European Institute for Marine Studies (IUEM), said: ‘Spiny lobsters produce these sounds to startle predators, such as octopuses and fish.
‘Interestingly, they can still produce sounds during the period following a moult – all crustaceans grow by changing their carapaces.
The little lobster with a mighty sound
The European spiny lobster is a nocturnal crustacean, whose scientific name is Palinurus elephas.
It is also one of the world’s most prized gourmet seafoods – leading to a dramatic decline in stocks.
Because of its high commercial value, Palinurus elephas has been historically overfished in many European waters.
This is especially due to the use of highly invasive and intrusive trammel nets, which bought this species to its current status of ‘Vulnerable’ on the IUCN Red List.
It is also known as the crawfish, crayfish or rock lobster. Instead of typical large pincers, it has two small hook-like claws.
Almost two foot long, it’s found around the South West of England, Wales and along the West Coast of Scotland.
Spiny lobsters are related to crabs and barnacles and live in crevices and caves amongst the rocks in shallow waters down to around 70m.
They gets their name from the spines that cover their shell, or carapace. They stay in their hidey-holes during the dayt and come out to feed at night.
They are scavengers and will feast on whatever they can find including crabs, worms, starfish and any dead animals.
‘This is when they are most vulnerable to predation because their exoskeleton is soft.
‘They may even use these sounds as a means of communication – and to warn other lobsters if a shark is in the area, for instance.’
The research, published today in the journal Scientific Reports, involved recording 1,560 antennal rasps using eight underwater microphones.
They were placed at various distances away from the lobsters, ranging from 16inches to 300 feet.
It revealed that the range of the noise was limited by the size of the animal. Sounds from bigger lobsters travelled further than rasps from smaller individuals.
The biggest and loudest lobsters, more than five inches long, were heard clearly at a distance of 300 feet during this experiment and researchers estimate that, if they’d have had more microphones, would have been able to detect the sound 1,300ft away.
This is despite high ambient noise levels in the shallow waters of the busy harbour of Brest where the study was carried out.
Taking this into account the spiny lobster may be heard over several kilometres in quieter coastal waters, the researchers speculate.
Mr Jezequel said: ‘In conditions of low background noise, rasps produced by the largest individuals could be detected up to 3 km (1.86 miles) away.’
Pictured, the defensive behaviour of two spiny lobsters. Scientists found the sounds produced by bigger lobsters travelled further than rasps from smaller individuals
The biggest and loudest lobsters, more than five inches long, were heard clearly at a distance of 300 feet during this experiment and researchers estimate that, if they’d have had more microphones, would have been able to detect the sound 1,300ft away. If there was no ambient noise, the sound could have been heard from 1.8 miles away, the scientists say