The Portuguese dogfish is commonly named the deepest-living shark, reported to about 3,675 meters. Cookiecutter sharks have also been reported near 3,700 meters, so differences in capture, observation and tagging methods make roughly 3.7 kilometers the most defensible answer.
At a glance
- Reported shark limit
- ~3,700 m
- About 12,100 feet below the surface.
- Record species
- At least two
- Portuguese dogfish and cookiecutter shark records reach this depth.
- Deep trenches
- No sharks
- Verified records do not extend into hadal depths.
Deepest reported shark records
| Species | Reported depth | How to read the record |
|---|---|---|
| Portuguese dogfish | About 3,675 m / 12,057 ft | The most frequently cited deepest-living shark record. |
| Cookiecutter shark | About 3,700 m / 12,139 ft | A similar published maximum; methods and ecological meaning differ. |
Maximum reported depth is not the same as a species' typical habitat or proof that it permanently lives at that exact depth.
What is the deepest shark in the ocean?
For a direct answer, use the Portuguese dogfish, Centroscymnus coelolepis, at roughly 3,675 meters. Keep the qualifier: the cookiecutter shark, Isistius brasiliensis, has a published depth near 3,700 meters, and different studies do not always measure depth in the same way. Both records place the known shark limit near 3.7 kilometers, or about 12,100 feet.
The record is shared
A review of fish colonization in the deep sea identified the Portuguese dogfish and cookiecutter shark as the deepest-recorded sharks, both at approximately 3,700 meters. A trawl capture, camera observation and vertical movement by a tagged animal do not answer exactly the same ecological question, so “deepest caught” and “deepest resident” should not be used interchangeably.
A surprisingly shallow ceiling
Bony fishes have been documented thousands of meters deeper. The absence of sharks from abyssal and hadal fish communities is therefore not simply a lack of fish food or sampling. Researchers have proposed that the chemistry sharks use to balance urea in their tissues becomes limiting as pressure rises.
Pressure meets biochemistry
Sharks retain urea to keep their body fluids near seawater’s osmotic concentration. Trimethylamine N-oxide, or TMAO, helps counteract urea’s destabilizing effect on proteins and also increases with depth in many marine animals. Models suggest the required chemical balance may reach a physiological ceiling for chondrichthyans near their observed maximum depth.
Why records can change
Deep-sea sampling is sparse, and many records come from fishing gear that integrates a range of depths. New tags and remotely operated vehicles could refine the limit or identify another record holder. A future observation somewhat below 3,700 meters would update the number; it would not automatically erase the broader pattern separating sharks from trench-dwelling bony fishes.
Quick answers
How deep can sharks swim?
Published shark records reach about 3,700 meters, or roughly 12,100 feet. That is deep, but still far above the deepest ocean trenches.
Do sharks live in the Mariana Trench?
There is no verified evidence of sharks living in the hadal depths of the Mariana Trench. Confirmed shark records stop thousands of meters shallower.
Why are there no sharks in the deepest ocean?
Researchers have proposed that pressure and the chemical balance sharks use to stabilize proteins and retain urea impose a physiological depth limit. Sampling remains incomplete, so this is a supported explanation rather than a final proof.
CHECK THE EVIDENCE