When divers resurface too quickly from deep water, the intense change in pressure can make gasses dissolved in their blood bubble up. This problem can lead to nausea, fatigue, joint pain, and paralysis. In the worst cases, it can be fatal. 

This is known as barotrauma, and it doesn’t only affect us. Dolphins, fish, and sea turtles can suffer severe injuries from sudden pressure changes. 

When anglers pull fish from water 30 feet deep and more, their catch is susceptible to barotrauma. Coming rapidly to the surface can make the swim bladder in fish inflate or rupture. This can lead to the death of the fish. 

If you’re deep-sea fishing and want to release a fish instead of eating it, you should know some myths about barotrauma: 

#1: If The Fish Isn’t Bloated, There Is No Barotrauma

Bloating is indeed the most common sign in a fish you’ve caught. However, some fish – including sharks and cobia – lack swim bladders. They might not show bulging eyes or float on the surface after you release them, but they still could suffer from gasses in their tissues, just like people. 

#2: A Fish That Swims Away Is Fine

Some anglers believe if a deepwater fish swims away with no apparent injuries that it doesn’t have barotrauma. Not necessarily. 

Research indicates that barotrauma can have effects later that we don’t always see when we release the fish. A fish might swim away but still be injured. Then, it could get eaten by a predator as it swims back to the reef. 

A barotrauma study on red snapper found that at least 15% of fish taken from deepwater died almost immediately. About 13% of fish were able to swim away but died within three days. So, nearly one out of three fish in the study did not survive catch and release. 

Reef fish, particularly the oldest and biggest females that produce the most eggs per year, are too valuable to the ecosystem to be lost at that rate. It’s essential for anglers who catch and release to use release methods that provide fisher with a better chance of living another day. Even a small improvement in survival rates for these fish can mean millions more fish are saved every year. 

#3: Venting Is The Only Way To Treat Barotrauma

Venting means puncturing the side of a fish’s body with a metal tool. When it is done right, venting can release the built-up gasses so they can escape from the bladder. This improves its ability to go back down deep and hopefully survive. 

But venting comes with problems. First, it can be hard to vent the fish correctly. You need to have a decent knowledge of fish anatomy. If you poke it a few inches the wrong way, you could damage the fish’s internal organs. Also, you should not vent a fish when the stomach is sticking from the mouth or when the intestines come out of the anus. This can kill the fish. 

Even if you vent the fish correctly, it still can suffer from the procedure, including a damaged swim bladder or infections. 

Venting does improve the chance the fish will survive, but there are other options. 

Try A Descending Device

A descending device returns the fish to deep water, where it can usually recover from barotrauma. You can use a descending device on any fish species, and you don’t even need to know fish anatomy!  The more anglers that use descending devices, the more likely deepsea fish will thrive. And that is good for our planet.