CATDOLL : CATDOLL: How do squids reproduce?

How do squids reproduce?

Reproductive system of squid: squids are dioecious, with no obvious difference in appearance. Reproduction is in vitro fertilization and direct development.

Females have one ovary, which is developed from the epithelium of the coelomic cavity and is located in the reproductive cavity at the rear end of the visceral mass. When the eggs mature, they fall into the cavity and are discharged by the thick oviduct, which has a thin end. The female reproductive opening is in the mantle cavity in front of the gill base. There is an oviduct gland near the end of the oviduct, and its secretions form the outer shell of the egg. On the walls of the visceral sacs on both sides of the rectum are a pair of large ovipositor glands, which open into the mantle cavity. Their secretions also form the outer shell of the egg and an elastic substance that hardens when it comes into contact with water, which can stick the eggs into egg groups. There is also a pair of small accessory ovipositor glands in front of the ovipositor glands, and their functions are unknown. During the reproductive season, the eggs mature and are produced in batches.

The male has one testis, located in the reproductive cavity at the rear end of the body, which originates from the coelomic epithelium. It is composed of many small tubes. After the sperm matures, it falls into the reproductive cavity from the small tubes. The vas deferens is long and tortuous. There are spermatophores and prostate on the tube. The end is swollen into a spermatophoresac, and the end is the penis. The male genital opening opens into the mantle cavity. There are a lot of spermatophores in the spermatophoresac. When the sperm reaches the spermatophoresac, it is covered with an elastic sheath to form a spermatophore.

Every spring and summer, cuttlefish swim from deep water to shallow bays to lay eggs, which is called reproductive migration. After laying eggs, cuttlefish die in large numbers near the coast. There are many types of cuttlefish in my country. The most obvious migratory ones are the needleless cuttlefish (Sepiella maindroni), which is abundant in the southern coast of Zhejiang and the coast of Fujian; the Taiwan squid (Loligo formosana), which is distributed in the sea area south of the Taiwan Strait, and the offshore waters of Shantou and the Beibu Gulf are spawning places. Squid like to lay their eggs on seaweed or wood chips, hanging on them like bunches of grapes. Therefore, coastal fishermen often bundle things like branches into bundles and throw them into the sea to lure cuttlefish to lay eggs. When groups of cuttlefish swim to lay eggs, they will set nets to catch them, which is very profitable.

The suitable temperature for spawning is 15℃～20℃, and the salt content is more than 30%. Before spawning, the male and female mate, that is, the male uses the stalked arm to send the spermatophore into the female's mantle cavity, the spermatophore breaks, and the sperm inside is released, and the sperm and eggs are fertilized in the mantle cavity. Soon after mating, the female will discharge fertilized eggs, which are round, slightly pointed at one end, about 10mm in long diameter, and accumulated together in a bunch. The surface is black and sticks to foreign objects, commonly known as "sea grapes". Squid eggs contain a lot of yolk and are terminal yolk eggs. After incomplete cleavage (disc cleavage), the gastrula is formed by the exophytic method and develops directly. The hatched larvae are similar to adults.

Only one known species of squid can take care of its offspring: the Agate Squid. The female squid swims with a large egg sac containing hundreds of eggs. The incubation period lasts for six to nine months, during which time the female squid does not eat at all, but simply guards the eggs. When the eggs hatch, her mission is completed and she dies. This is the first time in the world that a squid has been found that can take care of its offspring.

Squids are dioecious, with no obvious difference in appearance. Reproduction is by in vitro fertilization and direct development. Females have a nest of eggs, which develop from the coelomic epithelium. During the reproductive season, the eggs mature and are released in batches. Males have one testis, which is located in the reproductive cavity at the posterior end of the body and originates from the coelomic epithelium.

Before mating, the male squid changes its color to attract females and warn off rivals. Then the male and female lie face to face, arms entwined. Sometimes this results in a pair of mates strangling to death. The male uses his transformed arms to reach into his mantle and search for a sperm packet - called a spermatophore - which he deposits into the female's mantle, allowing the sperm to fertilize the female's eggs, which are usually deposited on the sea floor.

You want to raise money through farming?

How to raise arowana so that it can thrive?

Satisfactory answer

Arowana is a fairly easy fish to keep. It has excellent abilities and is not too picky about the environment it lives in. However, you still need to pay attention to some small details when keeping it so that the fish and the water tank remain in the best condition.

1. Aquarium: Arowana is over 20cm in size and belongs to medium to large cichlids. It has a strong sense of territory and is recommended to be kept in an aquarium alone. In addition, the size of the space will also affect the growth rate and body shape of Arowana. It is best to choose an aquarium over 1m to avoid restricting the growth of the fish. Using black or blue as the background of the aquarium will help Arowana present the most beautiful body color.

2. Bottom sand: Arowana prefers neutral or slightly acidic water. It is best to use river sand with a particle size of about 0.5-1 cm to keep the water quality neutral. The bottom sand can be laid to a thickness of about 5 cm. Avoid using driftwood or coarse stones in the layout of the water tank to prevent the fish from accidentally damaging their scales.

3. Water quality: No matter what kind of fish you are raising, good water quality is a very important part. Arowana is not very demanding on water quality, but because it eats a lot, you should choose a filter with good performance when raising it. This will not only keep the water clean, increase the dissolved oxygen in the water, but also help the growth of beneficial bacteria that maintain stable water quality. The water temperature is best around 26-27℃; the pH value is between 6.5-7.2.

4. Feed: You can use raw bait: shrimps, bloodworms, etc. and feed without artificial colors.

5. Lighting: Most tropical fish are kept in small outdoor ponds in artificial breeding farms. Due to long-term exposure to sunlight, their colors are very bright. When aquarium enthusiasts bring tropical fish home to raise them, if they do not provide the fish with proper lighting, the color of their body surface will gradually fade. It is recommended that the lighting be controlled for about 10 hours a day, which will have a positive effect on the health of the fish and the color performance.

In addition, since Luo Han is a strong and healthy person, as long as the water quality is maintained well and attention is paid to nutrition, there is little chance of disease.

Luohan fish bait is divided into two types: natural bait and artificial synthetic feed:

Natural bait:

There are two types of natural baits: live and dead. Fish are generally more interested in eating live baits. Live baits can increase the hunting ability and activity of fish, but the disadvantage is that live baits are covered with countless parasites and bacteria. This will directly affect the balance of the number of parasites and bacteria in the fish tank, and it is very likely to infect the fish, and the fish may be injured in the process of hunting live baits. If you need to feed live baits, it is best to isolate the live baits, deworm and sterilize them before feeding them to the fish, and squeeze them to stun them when putting them in the water, so that the fish can eat them more easily and reduce the injuries of the fish. Frozen natural baits (frozen bloodworms) or dried natural baits (dried shrimps) can be used for feeding because they have relatively fewer parasites and bacteria.

Artificial feed:

Artificial feed is divided into low-temperature dry feed and high-temperature dry feed. Dry feed below 60℃ can preserve higher content of nutrients and vitamins, while high-temperature dry feed above 60℃ has lower content of nutrients and vitamins. Low-temperature dry feed is cooler, while high-temperature dry feed is more likely to make fish get angry. Relatively speaking, the price of low-temperature dry feed will be more expensive. Foreign countries have been developing fish food for a long time, and now the competition for fish food is getting more and more fierce, so the nutritional value of fish food has become higher and higher, and more balanced, so artificial fish food occupies a very important position in the future breeding development. Under the deployment of different secret recipes, fish food will be formulated according to the growth stage of the fish with the different nutrients it needs to achieve the most ideal breeding pleasure. Natural and artificial fish baits have different advantages. Generally speaking, if you let it eat 2-3 meals a day. It is best to eat fish bait for the first and second meals, and give it natural feed for the third meal so that it can absorb balanced nutrition.