The Science Behind Blobfish Bloating

Why do blobfish become bloated when they are brought to the surface?

Blobfish, also known as Psychrolutes marcidus, are deep-sea fish that inhabit the cold waters off the coasts of mainland Australia and Tasmania. They live at depths of around 2,000 to 4,000 feet (600 to 1,200 meters) where the pressure is extremely high. When these fish are brought to the surface, where the pressure is significantly lower, they appear bloated or distorted.

The reason behind this bloating is primarily due to the gas-filled swim bladder in their bodies. The swim bladder is an internal organ that helps fish control their buoyancy, allowing them to either rise or sink in the water column. In the depths where blobfish dwell, the pressure is immense, and the swim bladder is compressed to a smaller size. This is essential for the fish to maintain its overall density and avoid being crushed under high pressure.

However, when a blobfish is suddenly brought to the surface, the pressure on their bodies decreases rapidly. The swim bladder, not having enough time to adjust and release the excess gas, expands because there is less external pressure pushing against it. As a result, the fish’s body appears puffed up, giving it a bloated appearance.

It is important to note that the blobfish’s adaptation to deep-sea conditions makes them well-suited to their natural habitat, but it also makes them extremely vulnerable to changes in pressure. Humans rarely encounter blobfish in their natural environment, but when they accidentally get caught in fishing nets or trawls and brought to the surface, their bodies may become bloated, causing them extreme stress and even leading to their unintended death.

In recent years, blobfish have gained some attention due to their unusual appearance when brought to the surface, which has led to their association with being one of the “ugliest” creatures in the animal kingdom. However, it’s important to appreciate their unique adaptations and the critical role they play in their deep-sea ecosystem.

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