In the seabed where the seaweed is luxuriant, there is a kind of cucumber-like animal living, which is covered with brown or pale green color, and there are a lot of prominent thorns on its body, which is the "ginseng" in the sea ---- sea cucumber. Sea cucumber is a valuable sea delicacy among echinoderms. There are more than 20 kinds of edible sea cucumbers in the China Sea, and some of them are expensive, such as the prickly ginseng, plum blossom ginseng, and the black wrinkled spoke anal ginseng.

On the coasts of Shandong Peninsula and Liaodong Peninsula in China, there is a kind of sea cucumber with large and small conical thorns on the back of its body, called the ginseng, on the bottom of the rocky reefs or fine sandy sea in the bay where the sea water is stable and quiet at a depth of 3 meters to 15 meters. Spiny ginseng is one of the most valuable sea cucumbers. It is very afraid of heat, whenever summer comes and the temperature of sea water rises, it will climb to the deep water, ambush in the vicinity of the reef, do not eat and do not move, and start the "summer sleep", and sleep until the mid-autumn season to start activities, and this sleep is enough to sleep for more than 3 months! When it is high and cool in autumn and the water temperature is getting cooler, the ginseng will crawl to the shallow water, and use the branch-like tentacles to grab the mud and sand containing rich organic substances on the seabed and devour them. The organic matter caught in the sediment is digested and absorbed, and the indigestible sediment is discharged from the body. It is the sea cucumber's feces that gives clues to those who dive to catch them.

Sea cucumber is not only a delicious dish on the table, but also a nutritional tonic, which has good effects on strengthening the body,

preventing diseases, suppressing tumors and prolonging life.

Swimmers--Pike

When you first dive, the fish you are most likely to see is the pike. With its razor-shaped teeth and pike-shaped body, the barracuda often swims around the boat waiting to be fed.

Pike often move around in schools when they are young and alone when they grow into adults. Large pike can reach up to 180 centimeters and have teeth up to 2.5 centimeters.

The curiosity of pike often leads them to approach divers, but there is no precedent for them to attack divers.

Squid

An animal in the sea that can spit ink is called a squid. It is also called cuttlefish because it can spit ink.

The squid can not only swim in the sea for a long time like fish, but also swim very fast. Some people call it "the rocket of the sea", which is a very appropriate metaphor.

In front of the head of the squid, around the mouth there are eight (divided into four pairs) radial arrangement of feet, squid feet on the top of the head, so we call this kind of animal cephalopods.

The squid's meat is very tasty, its meat contains a lot of protein, nutrition is very rich, so it is also with the fish and other shellfish, as well as become our very good food. There are a lot of squid caught along our coast every year. It is one of the four major seafoods in our country (the four major seafoods in our country are large yellowtail, small yellowtail, scallop and squid). Especially in the coast of Zhejiang, squid production occupies a very important position. Squid can be eaten fresh or made into dried squid.

Octopus

The octopus, like the squid, belongs to the cephalopod family,

because its feet are also born on top of its head. But it has only eight

feet, and not the tentacles that are specialized for catching food, like the squid. Its eight legs are so long that they look like eight bands, so fishermen call it the "eight-banded fish.

The octopus is also a fierce animal. On its feet there are large suction cups with strong suction power. If we catch a small octopus, hold it in your hand, it will immediately suck our hands with the suction cups, and it is very difficult to take it down!

The octopus also has an ink sac inside its body, and the ink it contains contains toxins, which not only

can be used to defend against enemies, but also can be used to attack enemies. An interesting fact is that

when the octopus rests, it does not rest its whole body together, but leaves one or two long legs on duty

shift and keeps turning. Even though its body and other feet have dulled its senses,

if the slightest touch is made to its duty foot, the octopus immediately jumps up and releases a thick

ink to hide itself.

Because the octopus has powerful feet and suction cups, and good defensive tools, animals its size in the sea

ocean are vulnerable to it. Even the largest and best-equipped

crayfish, whose bodies are about the same size as the octopus', inevitably fall victim to it.

The octopus' meat is fatty and also makes excellent sea food.

Luminous fish

In the marine world, whether it is the vast expanse of the sea surface, or 10,000-meter abyss of the seabed are living in all shapes and sizes, strange and bizarre luminescent organisms, such as a wonderful "undersea dragon official", all night long the fish lights shrimp fire brightly. It is they give no sunlight to the deep sea and the darkness of the sea surface to bring light. In fact, at least 44% of the fish in the dark layer have their own luminous ability, so that in the long night can see other objects, easy to hunt for food, looking for companions and mates. Some fish, such as the striped bass and dragonfish off the southeast coast of China, emit light from luminescent bacteria attached to their bodies, while many more emit light from the fish's own luminescent organs.

Candlefish have multiple rows of luminous organs on their abdomen and ventral side, like rows of candles, so they are called candlefish. The back of the head of the deep sea bald fish is flattened and covered by a pair of very large luminous organs, and the large luminous organs may play a role in vision.

Fish luminescence is a special enzyme catalyzed by a biochemical reaction. The luminescent fluorophore is catalyzed by the enzyme fluorophore, which absorbs energy, turns into oxidized fluorophore, releases photons and emits light. This is a special example of chemiluminescence, i.e., only luminous without heat. Some fish can emit white light and blue light, other fish can emit red, yellow, green and ghost fire-like shimmering light, there are also some fish can emit several different colors of light at the same time, for example, a deep-sea fish with a large light-emitting buccal organ that emits blue light and light red light, while other tiny light-emitting points throughout the body emit yellow light.

The biological significance of the fish's luminescence is fourfold: first, to trap food, second, to attract the opposite sex, third, for population bonding, and fourth, to confuse enemies.

The remora is a free traveler

The remora uses an oval-shaped suction cup above its head to attach itself to the bellies of whales, dolphins, sharks, and sometimes to the underside of ships, and to roam the world for free. Remora remoras use this technique not only to avoid enemy attacks, but also to eat the leftovers of large fish and sea animals, as well as food thrown off by the people on board. That's why they call them "free travelers".