Quick answers
Fish do bleed when hooked, though how much they bleed depends on a few key factors. Fish have blood and a circulatory system like humans and other animals. So when the hook pierces their mouth, gills or body, it wounds them and causes bleeding. However, fish blood clots more quickly than human blood. And being underwater, the bleeding is less visible. Plus, most fish have far fewer blood vessels in their mouths than humans. So a hook wound often bleeds less than a similar wound on a land animal. Still, fish feel pain when hooked, and some species are more sensitive than others. Proper handling and release methods can minimize harm.
Do fish have blood?
Yes, fish have blood and circulatory systems like humans and other vertebrates. Fish blood:
- Transports oxygen from gills to tissues
- Contains red and white blood cells
- Clots quickly to prevent blood loss
Fish blood cells:
- Red blood cells transport oxygen
- White blood cells fight infection
- Clotting cells promote quick clotting
So when a hook cuts a blood vessel, fish can and do bleed. Their blood coagulates quickly to prevent blood loss. But they still suffer tissue damage and pain.
Do all fish bleed when hooked?
All fish can bleed when hooked. But some species bleed more than others when caught:
- Trout and salmon bleed more from mouth wounds.
- Catfish bleed less due to tough mouth skin.
- Sharks have intense bleeding due to biology.
Trout and salmon have many blood vessels in their mouths to deliver oxygen to tissues. So mouth wounds bleed readily.
Catfish have tough skin in their lips and mouth. This offers some protection against cuts and bleeding.
Sharks have biological factors that cause intense bleeding when hooked. Their blood has higher clotting times. And their bodies maintain blood pressure unlike bony fish. These factors increase blood loss in sharks when wounded.
Why is fish bleeding less visible?
When fish are hooked, their bleeding is typically less visible than in land animals. Reasons for this include:
- Water washes blood away quickly.
- Rapid blood clotting helps limit blood loss.
- Less blood pumping to the wound underwater.
In the water, blood from a hook wound dissipates and is hidden from view. On land, blood pools visibly due to gravity.
Also, substances in fish blood promote faster clotting than in humans. Their blood starts clotting in under a minute versus 2-7 minutes for people. This adaptation stops blood loss faster when injured underwater.
Lower blood pressure in fish also limits bleeding. Less blood pumps under low pressure to the wound site, so less blood exits the injury.
For these reasons, fish blood is rarely seen when they are hooked. But make no mistake – they suffer tissue damage and pain beneath the surface.
Do mouth hooks or swallowed hooks hurt fish more?
Mouth hooks generally hurt fish less than swallowed hooks. Hooks piercing oral tissue damage fairly insensitive mouth areas. Swallowed hooks can injure sensitive internal tissues and organs.
Mouth hooks mainly cut lip and jaw areas. These outer mouth tissues have fewer pain sensing nerves. So injuries are less painful overall. However, some hooks can penetrate towards the tongue which has more nerves and blood flow.
Swallowed hooks pose more risk. They can lodge in the esophagus, stomach or intestines. These areas contain many blood vessels and nerves. So injury causes bleeding and significant pain. Also, removing swallowed hooks harms fish more.
Anglers should use barbless hooks and minimize swallowing to reduce harm. Deep hooking and prolonged play causes more oral injury and bleeding.
Do fish mouths have fewer blood vessels?
Yes, fish mouths contain far fewer blood vessels compared to human mouths. This difference explains why hooks cause less bleeding in fish:
- Fish have no lips, cheeks, complex tongue, etc.
- Their mouths are simply rigid bony structures.
- Minimal vessels are needed to supply basic mouth tissues.
- While human mouths have abundant blood vessels throughout.
For example, a single human tongue contains thousands of tiny blood vessels (lingual arterioles). This dense vascular network brings oxygenated blood to the tongue’s muscles and tissues.
By comparison, a fish tongue is a simple flap of rigid muscle with minimal blood vessels. Their mouths overall contain far fewer arteries and veins than land animals.
So when a hook snags fish lips or tongues, it severs fewer blood supply routes. This limits blood loss from the wound despite it being underwater.
Do fish feel pain when hooked?
Yes, scientific evidence shows fish do feel pain when hooked through their lips or mouth. Fish have:
- Nociceptors (pain receptors)
- Brain regions that process pain signals
- Pain reflexes like writhing
So like humans, fish sense injury through pain nerves, and experience discomfort in the brain. Mouth hooks clearly damage tissue, causing pain signals.
Some key signs fish feel pain when hooked:
- Struggling immediately when hooked
- Fight reflexes are triggered
- Increased respiration
- Writhing and shaking to shed the hook
These reflex reactions indicate hooking causes discomfort. Proper handling and prompt release helps minimize suffering.
Do some fish species feel more pain?
Some fish appear more sensitive to hook pain than others based on these factors:
- Number of pain receptors
- Brain processing of pain signals
- Observed reflex reactions
According to research, trout, salmon and bass react more intensely to hooks than do catfish, carp or suckerfish.
Trout and salmon have more pain nerve fibers in their mouths and lips. They also have more developed brains to perceive pain. These species certainly writhe more violently when hooked.
In contrast, bottom feeders like catfish have tough lip tissue and simpler brains. They seem to feel less pain, struggling less when hooked.
So fish species have varying sensitivities to tissue injury. Anglers should handle and release all fish gently regardless.
Do barbed or barbless hooks hurt more?
Barbed hooks generally cause more tissue damage and pain than barbless hooks. The barbs on barbed hooks maximize deep tissue penetration and retention. But this also amplifies tissue injury.
Barbed hooks have backward pointing protrusions that embed into flesh. These barbs make hooks harder to extract, like fishhooks with multiple tiny anchors. This deep-seated retention lacerates flesh extensively during hook removal.
Barbless hooks lack protrusions, so they do not embed as deeply. They still pierce tissue when setting the hook. But they can be removed with less tearing and trauma.
For these reasons, barbless hooks are advised by many fisheries. Barbless designs allow easier hook removal with pliers. This lowers injury rates and minimizes handling stress before release.
Does deeper hooking cause more pain and bleeding?
Yes, deep hook penetrations into a fish’s esophagus or gut cause more pain and tissue injury than hooks in the mouth.
Mouth hooks mainly penetrate the lip or jaw area. These areas have some natural armor and fewer pain sensing nerves. So mouth hooks tend to cause more surface level wounds.
Deep hooking risks more harm by:
- Piercing sensitive throat and internal areas.
- Injuring vital organs if swallowed.
- Causing greater blood loss.
- Increasing reflex struggling and pain.
Anglers should avoid deep hooking fish by setting the hook quickly before swallowing. Deeply hooked fish should be released by cutting the line rather than forcing hook removal.
Do fishing hooks designed for humans hurt fish less?
Sometimes. Hooks designed for human flesh and mouth structure may penetrate fish tissue differently:
- Human mouth hooks may catch less in bony fish mouths.
- Fish lip shape better matches some fishing hooks.
- Hook barb and point designs affect tissue damage.
For example, a round bend needlepoint hook could pierce human flesh easily but glide off rigid fish bone.
However, kirbed fishing hooks grip slippery fish lips well. The kirb optimizes purchase on oily fish skin that human hooks may lack.
Hook choices like barbless versus micro-barbed also impact tissue trauma. No definitive evidence proves human medical hooks hurt fish less when fishing. But the concepts warrant further study.
Do live bait hooks hurt more than lures?
Live bait like worms can promote deeper hooking than lures. So they potentially cause more mouth and internal injury:
- Live bait moves enticingly provoking engulfing.
- Fish tend to swallow live bait deeper.
- Gulping motions set the hook abruptly in tissue.
In contrast, lures trigger reaction bites onto metal hooks. This allows easier catch and release from the lip area.
However, bait hooks themselves do not inherently cause more pain and injury than lure hooks. Use of live bait just risks deeper ingestion. A deeply hooked lure damages sensitive throat areas too.
With any hooking method, allowing fish to fully swallow increases tissue trauma. Quick hook sets keep wounds localized to the mouth.
Conclusion
Fish do suffer tissue injury and pain when mouths are impaled by fishing hooks. All fish can bleed from hook wounds. But their underwater environment masks blood loss, and coagulation limits it quickly. Still, pain receptors and reflex reactions show fish feel hooking discomfort, especially deeply ingested hooks. While fish mouths have less vascular tissue than human mouths, piercings cause pain nonetheless. Some species like trout seem more sensitive while catfish appear less bothered. Overall, barbless hooks, minimized play, and careful release helps reduce harm. Responsible angling and proper handling practices minimize pain and bleeding in fish from hook injuries.