First of all, puffer fish
1, definition:
Puffer, commonly known as "bubble fish", "puffer fish", "river fish", "clam fish", "puffer fish" (Jiangsu, Zhejiang), "good fish" (Guangdong), "chicken bubble" (Guangdong), "turtle" (Guangxi) and "street fish" (Guangxi) It was called "lungfish" in ancient times. Generally speaking, it refers to the fishes belonging to dactyloideae, Tridentata, Tetradentata and Bermuda.
2. Morphological structure:
The puffer fish is round and prismatic, with gray-brown back, scattered white spots, and some of them are strip-shaped or worm-shaped. The abdomen is yellow and white, and there are small white thorns on the back and abdomen. The fish is smooth and scaleless, black and yellow. The gluteal fin is white, the lower edge of the caudal fin is milky white, and the other fins are yellow. The eyes are sunken and half exposed, and the upper and lower teeth have two teeth that look like human teeth.
The gills are small and inconspicuous, and the nostrils are located on both sides of the nasal sac process, and the nasal sac process is not bifurcated. The mouth is small, and the swim bladder is oval or oval, with air bags, and the abdomen expands when encountering the enemy. Pufferfish are generally 5 ~ 28 cm long, most of them are 10 ~ 20 cm long and weigh about 300 grams.
3. System functions:
① Muscle system:
The puffer fish muscle is mainly white muscle without intermuscular spines, which is a good raw material for making sashimi. The muscle membrane of wild puffer fish is white, while that of cultured puffer fish is mostly black, which reflects the quality difference between wild and cultured puffer fish sashimi when making sashimi.
(2), skeletal system:
Because the puffer fish has no ventral fin and bone system, the body vertebrae of the puffer fish have no ribs, and the abdominal skin expands to a great extent, which creates conditions for its abdominal distension habit.
③ Digestive system:
The puffer fish has a developed liver and a special shape, which accounts for a higher proportion in fish than other fish. It is a basically independent digestive organ. It is rich in fat and highly toxic, and its liver index is about 20% ~ 30%. During the development and maturation of gonads, the substances accumulated in the liver are transformed into gonads, so the volume and weight of the liver decrease with the development and maturation of gonads.
④ Reproductive system:
The puffer fish is hermaphrodite, fertilized in vitro and hatched in vitro. The gonads account for a large proportion of fish and the gonad index is high. Generally speaking, the gonads in mature individuals account for about 30% of the body weight. Its eggs are very small, with a diameter of about 65438±0mm, so the number of eggs per kilogram of fish can reach 200,000 to 300,000. Its subsidiary characteristics are not obvious, and it is difficult to distinguish between male and female. Male testicles are generally non-toxic, edible, and delicious, better than muscles, but ovarian toxicity is great.
4. Living habits:
① Abdominal distension habit:
A part of the puffer fish's stomach forms a special pouch, which is generally called an air bag or an air bag. It can inhale water and air, and can inflate the abdomen without the restraint of ribs and the strong contractility of the skin. This habit is related to active self-defense and threatening enemy harm, and also has the function of pretending to be dead to avoid enemy harm.
Generally, the abdominal prickles are developed, the back is slightly worse, and the tail is almost absent. These skin prickles can increase the defensive effect when the abdomen expands. In ontogeny, there is no abdominal distension before the thorn grows up. At this time, the body length of the fish is generally about 5 mm, such as the oriental pure red fin. At the stage of gonadal maturation, the habit of abdominal distension weakens or disappears.
② Vocal habit:
When the puffer fish is frightened or attacked by environmental changes, its teeth or other bones rub against each other, and at the same time its abdomen expands into a ball, so as to intimidate the enemy and prevent the enemy from attacking.
(3), eye movements and blinking habits:
The eyeball of puffer fish is slightly prominent, and it is often seen that its eyeball keeps turning when foraging, which is different from the habit of other fish turning their eyeballs; And there are many skin wrinkles around the puffer fish eyes. By moving these skin wrinkles back and forth, puffer fish can blink slowly, which is an obvious lateral habit.
5, toxins in the body:
The meat of puffer fish is tender and delicious. There used to be a saying that puffer fish is not fresh after eating, and puffer fish eats to death. Some coastal areas in China have the habit of eating puffer fish, which the Japanese regard as delicious. People who lack cooking experience of puffer fish should never eat it. People who die of puffer fish poisoning are common at home and abroad, even Japanese people who are experienced in eating puffer fish. It is said that hundreds of people die of poisoning every year.
6, toxic parts:
Changes in the position and season of tetrodotoxin: the position of tetrodotoxin is the internal organs of fish. Including gonads, liver, stomach and other parts, its toxicity varies with different breeding environments and seasons. According to the example of Yangtze river puffer fish and cultured puffer fish, the toxicity of each organ is: ovary → spleen → liver → blood tendon → eyes → gill harrow → skin → testis → muscle. The organ toxicity of cultured puffer fish (over 2 years old) is consistent with that of wild puffer fish, but the toxin content is low.