If you see these at the beach in summer, run away! Don't touch them with your hands

Due to the high temperatures in recent days, visiting the beach has become the first choice for many friends' summer activities, and "catching seafood" is one of the popular activities.

However, behind this joyful activity, there are many potential dangers. The rapid rise and fall of tides, hidden marine life, poisonous seafood species, and complex terrain can all become potential risk factors. Let's talk about these dangers, including some that the author has personally encountered...

Tragic experience!

I was catching a mantis shrimp on the beach and my thumb was pierced!

Let's first take a look at the case where the author was hit by a "shrimp" and broke the nerves in his fingers! What exactly happened? Are mantis shrimps so powerful?

The culprit is not an ordinary mantis shrimp, but a mantis shrimp!

The author caught a mantis shrimp on a tropical beach, and his thumb was pierced by the shrimp. Yes, it was pierced!

The killer shrimp (Source: Photographed by the author)

Ten days after being pierced by a mantis shrimp, my thumb was still numb, so I went to the hospital. Amid the laughter of other patients, "How could you still be hit by that thing?", the doctor gave a diagnosis: traumatic infection of the left thumb and damage to the finger nerve.

Medical records of injuries caused by mantis shrimp (Source: Photographed by the author)

Why does this shrimp have such great power?

Peacock mantis shrimp, also known as peacock mantis shrimp, are known for their bright colors and powerful forelimbs. Their forelimbs can strike at a speed of 23 meters per second, generating a force equivalent to a small-caliber bullet, and the strike rate is up to 50 times per second. The force generated instantly reaches 1500 Newtons, which is enough to shatter shells and crustacean shells, and can even break glass aquariums up to 3 mm thick. Peacock mantis shrimp mainly inhabit tropical and subtropical coral reefs and are one of the most aggressive and destructive predators in the ocean.

The process of a mantis shrimp attacking (Image credit: MARYAM TADAYON, Nanyang Technological University)

In addition to mantis shrimps, there is another type of shrimp commonly seen on the seashore, the pistol shrimp, also known as the pistol shrimp. There are hundreds of species of this species, and they are famous for their unique predation and defense mechanisms.

The claw of the pistol shrimp is particularly large and has a unique structure, which can produce a loud noise and high-pressure water flow by closing it quickly. When it closes, it will produce a high-speed bubble, and the pressure inside the bubble will drop suddenly, forming a cavitation effect. The shock wave and sound generated can reach 210 decibels, which is enough to stun or kill nearby small fish and other prey.

Pistol shrimp (Source: Photographed by the author)

The energy released instantly when the bubble bursts is extremely high, even close to the temperature of the sun's surface. Pistol shrimps mainly live in shallow tropical and subtropical sea environments, often coexisting with other marine organisms such as sea anemones. They not only rely on powerful weapons to hunt, but also use them to defend against natural enemies. They are rare "weapon masters" in nature, but it is difficult for them to hurt people.

Seaside fishing

Don't touch these seaside creatures

When you go fishing or snorkeling at the beach, in addition to being pinched or injured by crabs and mantis shrimps, the toxicity of these small seafood at the beach cannot be ignored! Some of these cute little ones may even be "only touched once in a lifetime"!

1. Don’t eat/touch these snails

The whelk is a small marine snail, usually 2 to 5 cm long. Its shell is spindle-shaped, covered with fine spiral lines, and is mostly light yellow or brown with irregular dark spots or stripes. The shell mouth is long and narrow, with slightly thick edges and a pointed protrusion at the bottom.

The toxicity of the snail comes from the toxins in its body, which can cause poisoning reactions. After people eat snails carrying toxins, they will experience abdominal pain, nausea, vomiting, dizziness and other symptoms. In severe cases, it may cause neurological symptoms such as muscle paralysis and difficulty breathing. Due to the strong toxicity and the lack of effective antidote, it is recommended to avoid eating unfamiliar snails, especially those from unknown sources.

The weaving snail (Source: Wikipedia)

In addition to the patterned snails, cone snails, porcelain snails and scaly snails are also poisonous. Cone snails contain potent neurotoxins, and their venom can cause muscle paralysis, breathing difficulties, and in severe cases, can be fatal. Although most species of porcelain snails are non-toxic, some species may carry low-toxic toxins that may cause mild skin irritation and paralysis after contact. Some species of scaly snails contain low-toxic toxins that may cause local pain and skin irritation after contact. When you are at the beach, you need to be careful to avoid touching these poisonous snails.

Cone snail (Source: Wikipedia)

2. Be careful with blue-ringed octopus

The blue-ringed octopus is small, usually only 12 to 20 cm (including the tentacles). When disturbed or threatened, the blue-ringed octopus displays bright blue or purple rings, which is how they got their name. When calm, their color is more muted, usually tan or gray. The blue-ringed octopus has a soft, oval body with eight tentacles, each with a suction cup. Its tentacles are flexible and can be used to catch prey and cling to rocks or corals. They have large eyes, located on both sides of the body, which provide good vision.

Blue-ringed octopus (Source: Wikipedia)

The venom of the blue-ringed octopus mainly contains tetrodotoxin, a potent neurotoxin. Tetrodotoxin can block the sodium ion channels in nerve cells, resulting in interruption of nerve signal transmission. The venom of the blue-ringed octopus is so toxic that even a trace amount of venom is enough to be fatal. The toxicity of its venom is about 1,000 times that of cyanide.

After being bitten by a blue-ringed octopus, poisoning symptoms usually appear within minutes, including severe pain, paralysis, difficulty breathing, nausea and vomiting. In severe cases, respiratory failure and death may occur. There is currently no specific antidote for tetrodotoxin, so timely supportive treatment (such as artificial respiration and cardiopulmonary resuscitation) is crucial after being bitten.

3. Don’t touch fish bones as they are very strong

The mudfish (Brown basketfish) is a medium-sized marine fish, usually 20 to 40 cm in length. Its body is flat and oval, covered with spiny scales and protrusions, which have good camouflage. The brown basketfish is mainly brown and red in color, with irregular dark spots scattered on its body, and there are also many hard spines and soft fins on the dorsal fin, anal fin and pectoral fin.

Mud fish (Source: Wikipedia)

The toxicity of the mudfish is mainly concentrated in the hard spines of its dorsal, anal and pectoral fins. These spines contain venom glands, which will inject toxins after being stung. Poisoning can cause severe pain, swelling and inflammation, and in severe cases may cause breathing difficulties and heart problems. Although the venom of the brown basketfish is usually not fatal, it is necessary to clean and disinfect it immediately after being stung, and seek medical attention as soon as possible to prevent infection and other complications.

In addition to mudfish, other common fish with venomous spines or venom glands at the seaside include stonefish, lionfish, scorpionfish, skates and ribback fish. The dorsal fin spines of lionfish and scorpionfish are highly toxic, the dorsal, anal and pectoral fin spines of lionfish contain venom glands, the tail spines of skates contain venom glands, and the tail spurs of ribback fish contain toxins. The stings of these fish can cause severe pain, swelling, inflammation and even more serious reactions. When you are at the seaside, you should be vigilant, avoid touching these creatures, and know basic first aid measures.

Stonefish, lionfish, scorpionfish, rays and ribfish (Source: Wikipedia)

4. Don’t touch a jellyfish if it stings you

Common jellyfish that can sting people at the seaside include jellyfish, purple jellyfish and box jellyfish. Jellyfish are common jellyfish along the coast of China. Their tentacles release toxins, causing severe pain and skin redness and swelling. Purple jellyfish are also common in coastal areas. Their tentacles contain strong toxins, which can cause severe skin burning and redness and swelling after being stung.

Purple jellyfish (Source: Wikipedia)

The box jellyfish is one of the most poisonous jellyfish, mainly distributed in tropical and subtropical waters. Its venom can cause severe nervous and cardiovascular system reactions, and even be fatal. After being stung by a box jellyfish, it may cause severe pain, breathing difficulties and heart problems. When you are at the seaside, you should try to avoid contact with these jellyfish, especially during the jellyfish breeding season. After being stung, you should use sea water to rinse the wound and seek medical help as soon as possible.

Beach trip

Protection must be done well!

In addition to being careful of the larger creatures mentioned above, you can't avoid being scratched by rocks when playing in the sea. Because the seawater and reefs are rich in microorganisms, the risk of wound infection is high.

Not long ago, I went to the sea and stepped on the mud after the tide receded in my slippers. I got quite a lot of small seafood, but my feet were scratched by the reef shellfish and covered with mud. The next day, the wounds became infected and my feet swelled up. The microorganisms on the seashore cannot be ignored. Here are some common pathogenic microorganisms.

The foot was cut while digging for shellfish in the mud (Source: Photo by the author)

1. Vibrio vulnificus

Vibrio vulnificus is a bacterium found in warm seawater, especially in the summer. Once it enters the body through an open wound, it can cause severe infection and even sepsis. The infection can cause severe pain, redness, swelling, fever and blisters. If not treated promptly, it can lead to necrotizing fasciitis (commonly known as "flesh-eating bacteria"), which can be fatal in severe cases.

In addition to Vibrio vulnificus, other Vibrio species such as Vibrio parahaemolyticus are also widely present in seawater. After entering the human body through open wounds, they can cause local infection with low pathogenicity. The main symptoms are local infection symptoms such as redness, swelling, pain, and abscesses.

2. Pseudomonas

Pseudomonas is a common environmental bacterium that is particularly active in moist and warm environments. It is transmitted through wounds and is more likely to cause serious infections, especially in people with weakened immune systems. When a wound is infected, pus, redness, swelling and pain usually occur, and in severe cases, it may lead to systemic infection.

3. Methicillin-resistant Staphylococcus aureus (MRSA)

MRSA is a highly drug-resistant bacteria that spreads through broken skin and can cause difficult-to-treat infections. The infection can cause redness, swelling, pain, pus, and in severe cases, sepsis and other serious complications.

Catching crabs in the mudflats (Source: Photo by the author)

Summarize

When fishing at the seaside, everyone should not only enjoy the fun of fishing, but also stay vigilant at all times to ensure their own safety. Not all small seafood can be eaten, and some seemingly harmless marine creatures may contain toxins or parasites, posing a threat to human health. Therefore, when catching unfamiliar seafood, be sure to handle it with caution. In addition, it is also crucial to take protective measures. Wearing gloves and water boots can not only protect the skin from the erosion of sea water and sand, but also prevent being stabbed by sharp shells or other marine creatures. Especially for those creatures that are unfamiliar or have never been seen before, never catch them directly with your hands to avoid accidents.

With scientific knowledge and adequate preparation, we can enjoy the fun of catching seafood while ensuring our safety. I hope every friend who catches seafood can have a happy and safe time this summer.

Author: Denovo, PhD in Analytical Chemistry

Reviewer: Huang Chengming, Researcher at the Institute of Zoology, Chinese Academy of Sciences

Reviewer: Wang Qian, Chief Physician of the Emergency Department, the Third Medical Center, PLA General Hospital