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Are fish traumatized by being caught?

Fishing is a popular recreational activity and sport around the world. Anglers enjoy the thrill of the catch and many eat or sell their catch. However, some people are concerned that fish may experience psychological trauma or distress when caught with a hook. In this article, we will examine the evidence on whether fish can feel pain and become traumatized, the impacts of catch-and-release fishing, and steps anglers can take to minimize harm.

Can fish feel pain and psychological trauma?

For many years it was believed that fish could not feel pain because they lack the neocortex region of the brain that humans have. However, more recent research indicates fish do have the capacity for a type of consciousness and can experience emotional states and feel pain.

Fish have opioid receptors and when given painkillers, their reactions to stimuli that would normally cause pain are reduced. When injured, they show protective behaviors. Researchers have identified specialized nerve fibers in fish that detect painful stimuli. Areas of the fish brain are active when the fish are in situations that would be painful for mammals.

When hooked, fish exhibit behaviors that signal they are in distress. They struggle, fight, and try to escape. Their breathing and body movements speed up. These are indicators that the fish is feeling pain or panic. After being caught and released, some fish show signs of learning to avoid bait and hooks, suggesting a negative experience.

So while fish may not conceptualize pain in the same complex way humans do, the evidence indicates they do feel pain and react to painful events. This means catching a fish causes real stress, fear, and physical suffering. The hook piercing their mouth and the fight to reel them in causes tissue damage and physiological stress. Once landed, the fish is experiencing exhaustion and anxiety.

This distress response evolved to promote survival. In nature, fish react with a flight or fight instinct to escape from predators. Being caught triggers the same genetic response, but when angled the fish is unable to get away from the threat. This creates a prolonged state of acute stress.

Impacts of catch-and-release fishing

Many recreational anglers practice catch-and-release fishing to avoid killing large numbers of fish. However, even when released, the process of being caught causes harm to the fish. Hooks can damage jaws and internal organs. Being reeled in rapidly changes pressure in the body cavity and causes tissue injury. Landing nets and handling on shore or in the boat causes scale loss, scrapes, and removes the protective mucus coating.

The exertion from the fight to reel in the fish leads to physiological stress. Blood chemistry changes and metabolic acidosis can occur. This leads to impaired breathing, cardiac function, and immune response after release.

Sublethal impacts that compromise survival after release include:

  • Injuries and bleeding from hook wounds and handling
  • Exhaustion
  • Ruptured swim bladders
  • Damage to jaws and eyes
  • Lactic acid buildup
  • Decreased reproductive function

Mortality rates in released fish are high. One summary of catch-and-release studies found an average mortality rate of 18%, although rates varied widely based on species, water temperature, and handling methods. Barotrauma, which is physical damage from pressure change, accounted for most mortality.

Even fish that appear unharmed and swim away normally after release may die later from the cumulative impacts. Delayed mortality rates can be up to 43% higher than initial observations would suggest.

So while catch-and-release rules allow more fish to be caught before bag limits are reached, the practice still causes extensive harm and death.

Can fish experience psychological trauma?

We know fish react to painful stimuli in a survival-oriented way. But can fish experience psychological states like fear, distress, or trauma? As awareness of animal sentience grows, more scientists are considering fish cognition and emotions.

Fish have good long-term memories and develop complex mental maps of their surroundings. Their brain structure includes regions involved in emotion and learning in other vertebrates. Studies show fish can be trained to perform tasks and they show signs of emotional fever if stressed.

There is evidence that fish display fear responses to stimuli they associate with threats and that some fish may even experience states similar to post-traumatic stress disorder. Changes in brain neurochemistry are seen after a stressful catch-and-release experience.

One study trained trout to associate a light signal with a fearful event. Fish showed signs of anticipatory fear and anxiety when they were re-exposed to the light cue. This demonstrates fish can experience negative emotional states.

So while fish psychology is still poorly understood, it seems probable that the experience of being hooked, fighting against the pull, and being unable to escape could induce trauma and lingering fearful behavior.

Welfare of fish in commercial fishing

Recreational fishing accounts for only about 11% of global fish catches. The vast majority of wild caught fish come from commercial fishing operations. This raises significant ethical concerns about the welfare of commercially caught fish.

Fish caught in nets or on longlines struggle violently to escape and can suffer exhaustion, scale loss, crushing, decompression injuries, and suffocation. Towed fishing gear like trawls and dredges can cause terrible injuries as fish collide with debris and the net walls. Bycatch, which is non-target fish caught and discarded, amounts to 40% of global catches and most die after release.

Conditions during storage aboard ships often lead to high mortality rates due to stress. Unloading and onshore processing involves crowding fish into tanks which limits oxygen. Then fish are slaughtered through methods like live gutting, asphyxiation on ice, and carbon dioxide stunning. These methods may not cause an immediate or humane slaughter.

Living conditions and slaughter in aquaculture also pose welfare challenges. Crowding, poor water quality, and injuries from aggression lead to chronic stress. Slaughter methods sometimes cause suffering, such as live chilling on ice.

The commercial fishing industry provides little transparency around their fishing practices and how fish are handled and killed. But it is clear that large numbers of fish experience significant welfare threats before slaughter.

Steps anglers can take to minimize harm

While any sport fishing poses risks to fish welfare, anglers can take steps to reduce trauma and increase chances of survival:

  • Avoid fishing during hot summer months when warm water increases stress
  • Use barbless hooks which allow easier hook removal and cause less damage
  • Rig gear to allow break-offs so fish can escape with the hook
  • Minimize fight time by not using excessively heavy line/rods
  • Use rubberized nets or cradle fish while unhooking
  • Keep fish in water when handling and releasing
  • Revive exhausted fish in an aerated livewell or by moving them slowly in figure 8 patterns
  • Avoid areas where deep water fish may experience barotrauma

Learning how to handle fish carefully, use selective gear, time outings around fish welfare, and implement catch-and-release best practices allows anglers to enjoy the sport while minimizing negative impacts.

Some anglers are also moving towards plant-based lures and artificial flies to completely avoid injuring fish with hooks.


Modern research shows fish are sentient animals capable of feeling pain and psychological states of distress, fear, and anxiety. When caught with hook and line, fish exhibit a vigorous panic response because they are unable to escape the perceived threat. This causes physiological stress and tissue injury.

Even with catch-and-release practices, fish experience significant sublethal impacts and post-release mortality is high. Evidence suggests fish can develop trauma and conditioned fear responses after capture.

Commercial fishing also causes immense fish suffering from injuries, exhaustion, and inefficient slaughter methods.

Anglers can take many steps to improve welfare of caught fish and reduce mortalities. But ultimately, the most ethical choice is to forgo recreational fishing when its goal is merely sport and entertainment at the cost of animal welfare. Catching sentient animals causes inherent harm we should thoughtfully consider.