Bringing a deep sea fish to the surface can have severe consequences for the fish due to a phenomenon known as barotrauma. Deep sea fish are adapted to survive in the extreme conditions of the deep ocean, which include high pressures, low temperatures, and darkness. When these fish are rapidly brought to the surface, several physiological changes occur that can be harmful or even fatal to the fish. Here are some of the effects:
Expansion of swim bladder: Many deep sea fish possess a gas-filled organ called a swim bladder that helps them control buoyancy. As they ascend to the surface, the reduction in pressure causes the swim bladder to expand rapidly, which can lead to the fish experiencing extreme discomfort or even rupture of the swim bladder.
Decompression sickness: Deep sea fish are adapted to withstand the high pressures of their natural habitat. Rapid ascent to the surface causes the gases dissolved in their tissues to come out of solution, forming gas bubbles. These bubbles can block blood vessels, leading to a condition similar to human decompression sickness or "the bends." It can cause internal injuries, damage to organs, and even death.
Temperature shock: Deep sea environments are characterized by cold temperatures. When deep-sea fish are brought to the surface quickly, they are exposed to a sudden change in temperature, which can shock their systems and lead to physiological stress.
Sensitivity to light: Deep sea fish are adapted to extremely low light conditions. Exposure to bright sunlight at the surface can damage their sensitive eyes and disrupt their vision.
Overall, the combination of pressure changes, gas expansion, temperature shock, and light exposure can cause significant harm to deep sea fish when brought to the surface. It is important to handle these fish with care and, whenever possible, release them at a depth that matches their natural habitat to increase their chances of survival.