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How loud is a pistol shrimp?

183–189dB re 1 µPa1 m

A single snapping shrimp's snap measures 183 to 189 dB re 1 µPa (peak-to-peak) at 1 m, according to Au and Banks's measurements of 40 shrimp. The sound does not come from the claw closing but from the collapse of a cavitation bubble, which can stun or kill small prey.

Level
183–189 dB re 1 µPadecibels relative to 1 micropascal, measured in water
Distance
1 m1 m
Daily limit
Underwater levelnot an air level

What the numbers mean

How it was measured. Underwater level in dB re 1 µPa. Underwater decibels are not comparable with in-air decibels: see "underwater-vs-air". Peak-to-peak source levels of 183 to 189 dB re 1 µPa for Synalpheus paraneomeris measured 1 m from a hydrophone in Kaneohe Bay, Hawaii (Au and Banks 1998). Peak-to-peak figures read higher than rms figures for the same snap.

Au and Banks kept individual shrimp in a small cage 1 m from a broadband hydrophone and digitised ten snaps from each of 40 animals. Peak-to-peak source levels ranged from 183 to 189 dB re 1 µPa and rose with claw size and body length. A typical snap carried about 3 W of acoustic power, with most energy at 2 to 5 kHz and some extending to 200 kHz. DOSITS gives the same upper figure, peak-to-peak source levels as high as 189 underwater dB at 1 m.

High-speed filming by Versluis and colleagues showed why. Snapping the claw shut fires a water jet fast enough to form a cavitation bubble, and the sound is emitted when that bubble collapses, not when the claw closes. The snap can stun or kill prey. A follow-up study found the collapsing bubble even emits a flash of light, implying temperatures of at least 5,000 K inside it.

Colonies of snapping shrimp crackle constantly and can dominate background noise in shallow tropical waters, which is a problem for sonar and for animals that rely on sound.

Is it dangerous?

Measured in water against a 1 µPa reference, so the number cannot be compared directly with levels in air. See the underwater note on the Scroll. Marine-mammal and diver exposure criteria use their own metrics and are outside the scope of this page.

Protecting your hearing

No risk to people. Divers on tropical reefs hear the colonies as a constant crackling.

Questions

How loud is a pistol shrimp snap?

183 to 189 dB re 1 µPa (peak-to-peak) at 1 m. Underwater decibels are not the same as air decibels.

How does a pistol shrimp make its sound?

Its claw fires a jet of water that forms a cavitation bubble; the bang comes from the bubble collapsing.

Can a pistol shrimp kill fish?

Its snap can stun or kill small prey animals, according to Versluis and colleagues.

Sources

  1. The acoustics of the snapping shrimp Synalpheus parneomeris in Kaneohe Bay (Journal of the Acoustical Society of America, 1998; abstract via Crossref), Journal of the Acoustical Society of America (Au and Banks, 1998). Supports: dB_low 183 / dB_high 189 re 1 µPa peak-to-peak.Peak-to-peak source levels varied from 183 to 189 dB reChecked 2026-11-02.
  2. The acoustics of the snapping shrimp Synalpheus parneomeris in Kaneohe Bay (Journal of the Acoustical Society of America, 1998; abstract via Crossref), Journal of the Acoustical Society of America (Au and Banks, 1998). Supports: Measured at 1 m.housed in a small cage located 1 m from an H-52 broadband hydrophoneChecked 2026-11-02.
  3. What are common underwater sounds?, DOSITS, University of Rhode Island (Wayback Machine copy). Supports: Up to 189 dB at 1 m.peak-to-peak pressure source levels as high as 189 underwater dB at 1 mChecked 2026-11-02.
  4. How snapping shrimp snap: through cavitating bubbles, Science (Versluis et al., 2000) via PubMed. Supports: Mechanism.the sound is emitted at the cavitation bubble collapse and not on claw closureChecked 2026-11-02.
  5. Snapping shrimp make flashing bubbles, Nature (Lohse et al., 2001) via PubMed. Supports: Shrimpoluminescence.extreme pressures and temperatures of at least 5,000 KChecked 2026-11-02.

This page is general information, not medical advice. If you have ringing in your ears, muffled hearing or any change in your hearing, see an audiologist or your doctor.