Imagine reeling in a weird-looking creature from thousands of feet below the ocean surface. As it gets closer to the top, its eyes bulge, its stomach pushes out, and its body swells up like a balloon before bursting apart right before your eyes.
This gruesome exploding fish phenomenon happens because of the huge change in pressure between the deep sea and the surface. Let’s look at why this happens and how we can prevent deep sea fish from exploding.
See also: Can you eat deep sea fish?
Why Deep Sea Fish Can Burst at the Surface
Deep sea fish live under immense pressure in the deep ocean, which can be up to 1,000 times greater than surface pressure.
To put it into perspective, the pressure at that depth is equivalent to a large elephant standing on your thumb.
This high pressure is needed to counteract the buoyancy of gases and fluids in their bodies so they can maintain neutral buoyancy.
When deep sea fish are brought to the surface too quickly, the rapid drop in pressure causes gases and fluids in their bodies to rapidly expand. This can cause deep sea fish to rupture or even appear to explode on the surface.
|Depth||Pressure||Times Greater than Surface Pressure|
|100 m||5 atm||5x|
|500 m||15 atm||15x|
|1,000 m||30 atm||30x|
|3,000 m||90 atm||90x|
|6,000 m||180 atm||180x|
The Swim Bladder
The main cause of exploding or rupturing is expansion of the swim bladder. The swim bladder is a gas-filled organ that many deep sea fish use to control buoyancy. Under high pressure, gases in the swim bladder are compressed.
When pressure drops at the surface, these compressed gases rapidly expand, which can cause the swim bladder to burst. This rupturing of the swim bladder is called barotrauma.
Other organs and tissues can also be affected by the huge pressure change:
- Eyes – The pressure drop can cause eyes to bulge and rupture.
- Stomach – contents can expand and be forced out.
- Heart – Can fail due to pressure changes.
- Tissues – Expanding gases and fluids can rupture throughout the body.
This expansion of gases and fluids makes it appear like the fish’s body explodes.
|Depth||Time Needed for Safe Decompression|
|100 m||30-60 minutes|
|500 m||2-3 hours|
|1,000 m||5-8 hours|
|3,000 m||48-72 hours|
Proper Decompression Needed for Survival
To avoid barotrauma and increase survival, deep sea fish need to be slowly decompressed when being brought to the surface.
Special pressurized tanks are used to gradually adjust the pressure and give deep sea fish time to adapt safely. This prevents over-expansion of gases and fluids in their bodies.
Fish Without Swim Bladders Less Prone to Exploding
However, these fish still need proper decompression when brought to the surface, as they can still experience barotrauma in eyes, stomach, and other organs due to pressure changes. Gradual decompression helps their survival.
In summary, the huge pressure change causes gases and fluids in many deep sea fish to expand rapidly when brought to the surface, which can make them appear to explode. Proper decompression procedures are essential for their survival, unless of course you plan to eat them anyway!