top of page

HANDS OFF! Why we should not touch marine life

scorpion fish diving Nusa Penida
So tempting to touch to feel the texture but it means tears for marine creature or human

it is a natural human instinct to touch. When presented with a new object, our first impulse is to touch it to find out more about it. Our brains can decipher a lot of information by using touch; we can assess weight, texture, density, temperature, the list goes on. So it seems only normal that when we are in a new environment - like diving in the ocean - we would want to touch everything. So why shouldn't we touch marine life? Our touch can have an enormous detrimental impact on marine life and should be avoided if we want to keep our oceans healthy.

Why we should not touch marine life: Our skin

Human skin is an ecosystem in itself. Our skin is colonised with an abundance of microorganisms including bacteria, fungi, viruses and even mites! They live on our skin, without us knowing, mostly harmlessly, sometimes even beneficially. However, these microorganisms are very specific for each person and the transferring of our own microorganisms to that of another person can cause illness. Therefore, it should be no surprise that introducing these microorganisms to an entirely different group of species, like that of marine life, can have severely adverse effects.

When we touch marine life in the ocean, whether it be corals, fish, sharks or anything else; our bacteria is transferred to them. This introduction of foreign microorganisms can have a devastating effect. Our bacteria and viruses, on them, can introduce diseases and infections that their immune system cannot defend against, leading potentially to death. It will also interfere with their own layer of protective microorganisms, which can impede their immune system, leading to illness.

Why we should not touch marine life: Mucus layer

All marine life, like ourselves, is also covered in a protective layer of microorganisms, called a mucus layer. This serves as both a barrier from their immediate environment and also contains antimicrobial components that provide innate immunity. If we touch this mucus layer, we simultaneously remove it, whilst introducing our own colony of microorganisms. This breaks their protective barrier and can introduce disease and cause life-threatening symptoms.

Just as we can harm marine life by introducing our bacteria to them; their bacteria will also harm us. Even the smallest cut on our skin will be a big enough opening for their bacteria to infect us. Our immune system may be able to combat some of the diseases or illnesses caused by foreign bacteria, however, the ocean is very large and we are still discovering new species every day – I’m not sure I would risk introducing alien bacteria into my ecosystem!

frog fish diving
Nope we don't get to find out what the frog fish skin feels like

Why we should not touch marine life: Physical Damage

There is also the physical damage we can do. When we touch, kick or accidentally knock marine life we can break or destroy it. Coral structures take years and years to form. They have a very specific balance and multiple intricate symbiotic relationships to ensure their survival. Even the slightest touch can break off delicate corals – this leaves them potentially without a life source, stopping their growth and exposing them to potential predators. A fin kick too close can displace smaller life; Tiny life can get ripped from the safety of their home in a rock or coral, and get thrust away with the force of water, landing exposed and easily spotted by passing predators – as well as somewhat confused I would think! We should always be aware of where are fins are and not use our arms to avoid unnecessary movements. Of course, buoyancy is the key to staying away from the corals and off the bottom and remains the best way to protect our marine life from accidental damage.


Beautiful as they may be, some species in our oceans use venoms, poisons and toxins to defend themselves and/or as a means of catching their prey. These toxins can have a deadly effect on humans, and yet another reason why we should not touch marine life;

The magnificent Lionfish has venomous spines which it uses defensively. A puncture from one of these spines releases the venom, which in humans can cause serious pain, difficulty breathing and even paralysis!

The hard-to-spot Stonefish is known to be one of the most deadly fish in the world! It has spines along its dorsal fin, which like the lionfish, delivers its venom when punctured. The venom of the stonefish is fatal to humans and causes extreme pain, tissue necrosis and heart failure. The biggest danger of the stonefish is how expertly camouflaged they are - you may think you are just resting your hand on a rock - but it could be a stonefish!

The deadly Black Banded Sea Krait uses its venom to paralyse its prey before swallowing it whole. They are nocturnal, hunting in the crevices of corals and rocks and can hold their breath for up to 30 minutes. Their venom is ten times more deadly than that of a cobra or rattlesnake, however, they are known to be fairly docile so bites to humans are relatively uncommon.


As well as the venomous creatures we need to be aware of - there is a variety of poisonous species, some of which are deadly to humans. Poisons must be ingested to have an effect; a good excuse to not eat the strange and wonderful life in the ocean.

The Pufferfish is known to be the most poisonous of all; its poison is 1200 times more poisonous than cyanide and can kill 100 humans with one dose! Nudibranchs manage to simultaneously store and absorb the toxins from the animals they consume, which in turn makes them toxic to anything that eats them! The Blue-Ringed Octopus, another powerful competitor, is both venomous and poisonous! Only a few centimetres long, not only does it produce a neurotoxic substance throughout its body, which acts as a poison and is fatal if ingested; but the blue-ringed octopus can also choose to inject the substance as a venom in its bite!

Take away

We have all been on a dive and been tempted to touch things; a passing turtle, shark or interesting shell, but it is important for us to remember the impact this small action can have. Not only are we potentially causing it harm, but we also risk damaging their habitat and ecosystem and interfering with their behavior, while risking our own health and safety too. We must learn to be responsible and control our human impulses. It is important to act as a role model to others and to ignore and certainly not follow the irresponsible actions seen on social media. Let's keep the ocean and its inhabitants happy and healthy by taking only photos and leaving only bubbles...


bottom of page