Growth environment of abalone

Abalone is widely distributed, while Haliotis discus hannai is mainly produced in the Yellow Sea and Bohai Sea. It is a kind of abalone with high economic value. It has life habits such as clear water quality, abundant seaweed, smooth water flow and stone holes. Let's take a look at the growth environment and growth cycle of abalone.

Growth environment of abalone

1. Abalone lives in rocky areas with fast currents and lush seaweed, and they like to live on coastal islands or protruding rock corners of the coast. Abalone mostly crawl in cracks or caves in reefs, and their water depth varies with species. Like abalone in northern China, it is generally distributed at a depth of more than ten meters, and moves to a depth of up to 30 meters in winter to avoid the cold. Slowly move up in the spring, some can live a few meters below the tide line, and small abalone can be picked even near the low tide line.

2. Abalone likes to sleep during the day and go out at night. Abalone raised in the pool are generally dormant during the day and move slowly as long as it gets dark. Especially after 10:00 to before 3 o'clock at night, their heads and feet are all extended, and the tentacles on the cracks in the mantle protrude from the shell hole and crawl at the bottom or wall of the pool. They can crawl at speeds of up to 50 centimeters per minute. Abalone also have the habit of homing. They often like to live in caves, go out to find food at night, and return to live in caves just before dawn.

3. Abalone likes to eat brown algae or red algae, such as abalone like undaria, tender kelp and sargassum. Abalone raised in the pool can eat dozens of grams of small kelp every day. The food intake of abalone varies with the season, generally eating more in the season with higher water temperature, less active in winter and eating less. When people put kelp into the pool where abalone is raised, although the head of the abalone is shrunk in the shell, relying on this more sensitive sense of smell, it can quickly find the direction of the food and climb to the kelp. When the food is still some distance from its body, it can stretch the two leaves at the front of the foot, pull the food to the edge of the mouth in a clasping position, stick out a disc-shaped snout and lick it with its tongue. The kelp they have eaten often has large round holes with rafter teeth on the edge.

The growth cycle of abalone

The growth of abalone is relatively slow in the shellfish family, starting with fertilized eggs and growing to 6-8 cm in commercial specifications, which usually takes 1-4 years or more. Chinese abalone, for example, takes nearly 3 years to grow to about 7 cm.

The growth rate of abalone decreases with the increase of age, and the growth pattern of abalone shell is similar to that of tree ring in the growth process. Whether the growth pattern is obvious or not is related to the environmental season and the species of bait. In the season of rapid growth, the growth pattern is obvious and the distance is wide. In the season of slow growth, on the contrary, the growth lines are dense and the distance is relatively close. Sometimes it is not easy to judge the exact age of the abalone shell directly from the growth pattern on the front of the abalone shell. We can clean up the algae, limeworms and other things attached to the shell and see through their annual rings with electric light.

Culture conditions of abalone

The most suitable water temperature for growth of abalone is 10-20 ℃. Taking the main abalone variety black abalone in Fujian as an example, the growth became slow when the temperature reached 26-29 ℃, but stopped when the temperature was below 14 ℃. Therefore, farmers send abalone to the south in winter, and farmers in the south send abalone to the north in summer. There are many ways to cultivate abalone, including bottom sowing culture (also known as natural proliferation), raft cage culture, factory culture and tunnel culture, etc., no matter which culture method, the choice of fresh water quality is particularly important.

1. Seaweed breeds and is rich in bait.

2. The water is clear and smooth, the proportion of sea water is stable, and the sea area is maintained at more than 1.020 in the whole year.

3. The bottom material is reef rock.

4. The sea area has no industrial pollution, few enemy organisms, no freezing in winter and floating ice in spring.