The largest shell in the world

Flame shell is a peculiar shell discovered by British researchers at the bottom of Walsh Bay in June 20 13. It looks like an anemone, and its red tentacles are like burning flames in color and shape, so it is called? Burning shells? , mainly feeding on small fish, shrimp and some zooplankton. Next, let's continue to learn about the world's largest scallop!

The largest scallop in the world

The discovery of flame shells

Researchers found at least 654.38 billion burning shells on the seabed while investigating Walsh Bay between Skye and the Scottish mainland. The director of the Scottish Environmental Protection Agency said that this may be the largest flame shell community in the world.

The Scottish Maritime Bureau discovered this biome when it was commissioned to conduct an investigation, which is part of the work to confirm the new marine protected area. This little scallop-like creature has many neon orange tentacles between two shells. These shellfish gather at the bottom of the sea, and their nests provide coral reefs for hundreds of other species to live on. The reef area of Huobei in Walsh Bay is also much larger than expected, with an area of 75 hectares.

Great challenge

Richard Lochead, director of the Environmental Protection Agency, said that the waters around Scotland are a hotbed of biodiversity. He said:? The water area of Scotland is about five times that of land. Trying to learn more about our precious and diverse marine life is a great challenge. This burning shell with orange tentacles will surely be considered as the most extraordinary species in our ocean. ?

He went on to say: many people will put such alien species on distant tropical reefs, and they don't realize that they just live underwater in the waters of Skye. This kind of flame shell not only looks beautiful, but also these mysterious shells can form reefs, providing a safe and diverse environment for many other species. ?

The Walsh Bay survey was conducted by Heriot Watt University on behalf of the Scottish Maritime Bureau. Dan Hari of the School of Life at Heriot Watt University said? When we look for early records of special species or habitats, we find that they are either destroyed, struggling or even extinct, which is often the case. To our delight, in this case, we found a huge flame shell community living at the entrance of Walsh Bay. This is a very surprising discovery for all who care about this survey. ?

Scallop is a synonym for bivalve mollusk of the genus Scallop, with about 400 species. There are more than 60 species in this family, which is one of the important marine fishery resources in the world. Shells, meat and nacre have high utilization value. Many scallops are eaten as delicacies. Scallops with bright colors and radial patterns are loved by collectors, and the patterns are adopted as works of art. Scallops belong to Pinctada, a subclass of Bivalves. Widely distributed in all sea areas of the world, with the tropical sea being the most abundant. About 45 species have been found in China, among which Chlamys farreri, Chlamys farreri and Chlamys farreri are important economic species. Scallops, also known as sea fans, are delicious and nutritious. What's after it's obturator internus dried? Scallop , is included in one of the eight treasures.

Species classification of scallops

Scallop is one of the main cultured shellfish along the coast of China. There are more than 60 kinds of scallops produced in the world, of which China accounts for about half. The common species of scallop culture are Chlamys farreri, Argopecten irradians and Chlamys yessoensis. It can be seen that there are rich varieties of scallops in China.

(scallop)

Variety source: Yellow Sea

Features: It belongs to mollusk, bivalve, Claudian, Heteropoda, Scallopidae and Scallop. Living on rocks and sandy seabed from 3m to 30m; Filter feeding, the bait is mainly phytoplankton; Temperature range-1.5℃ ~ 25℃; The suitable salt range is 16? ~43? ; The spawning period is May to June; It has a wide range of uses, tender meat, delicious taste and high economic value.

It is a natural species in China's sea areas. It is suitable for aquaculture in China's vast sea areas, especially in the northern coastal areas. Chlamys farreri is attached to life and has well-developed feet. The height of adult shells can reach more than 8 cm. Named after the right shell front ear has obvious foot holes and several fine comb teeth. The growth line of the shell surface is thin, with radial ribs of different thickness; The left shell is about 10, and the right shell is about 20 pieces, with irregular microprotrusions on the ribs.

(bay scallop)

Variety source: 1982 introduced from America.

Bay scallop is not suitable for breeding in China, mainly because the individual filtration capacity of bay scallop will reach 1.2 cubic meter to 1.5 cubic meter within 24 hours. With the increase of scallop culture area in China, the water quality in a large area is too high and the dissolved oxygen is too low. The output of scallop is less than one year, other cultured organisms are greatly reduced, and the seabed silt is thickened. As a result, China's marine environment will be seriously damaged, and personal opinions will be quickly generated by fisheries and environmental protection departments.

Features: Mollusca, Claudiobranchia, Heterocladocera, Scallopidae, Scallop. The shell is fan-shaped, the two shells are almost equal, the rear ear is larger than the front ear, and there is a foot hole under the front ear. There are 18 radiation edges on the shell surface, and the shell surface is dark brown or brown. The optimum growth temperature is 5-30℃ and 18-28℃.

Chlamys farreri

Chlamys farreri Chlamys farreri is named Jones et Preston. The common names are scallop clam (composed of its obturator internus) and sea fan, which belong to mollusca, Cladosporium, Pinctada, Chlamydae and Scallop.

morphological character

Big shell, measure scallops. Generally, the shell is 74cm long, 77MM high and 27.5 mm wide. The size and sides of the shell are slightly symmetrical, and the right shell is flat, with many different thicknesses of radiation on it. The size of the front and rear ears of shells is different, the front is big and the back is small, and the shell surface is mostly light gray.

Ecological habit

Chlamys farreri lives below the low tide line, with fast current, high salinity and high transparency, and the water depth is 10-30m on the rocky reef or hard seabed with shell gravel. It lies on the attachment base, its feet are connected, and its right shell is below. Animals can open and close their double shells to drain water and swim a short distance in response. Closing the shell can make a crisp sound and you can swim in the water with your feet off. In normal life, two shells are usually opened to filter unicellular algae, organic debris and other small microorganisms in seawater. If the environment doesn't adapt, the crural line can be cut off automatically, and the shell muscles can expand and contract quickly, relying on the power of shell opening and closing drainage and the power of ocean current for short-distance movement. Chlamys farreri has strong low temperature resistance and can survive below 0℃. 15-20℃ is the optimum growth temperature. When the water temperature exceeds 25℃, the growth is inhibited, and the shells can hardly grow below 4℃. For high salinity species, the optimum salinity range is 23-34. Chlamys farreri has high oxygen consumption rate and poor manna resistance.

Origin and season

It is produced in the northern coastal areas of China, mainly in Shandong Long Island, Weihai, Penglai, Shidao, Wendeng, Dalian, Liaoning and Changshan Island.

Reproductive characteristics

Chlamys farreri is hermaphrodite, and there is hermaphroditism. In the breeding season, the female gonad is orange and the male gonad is milky white, which is obviously different. After the breeding season, the gonads degenerate, and the male and female shapes are the same, showing colorless and translucent shape. Chlamys farreri has two breeding periods every year. The first time was from May to July, and the water temperature 14-20℃. The second time was from September to June, and the water temperature was 22-20℃. The breeding season is mainly related to water temperature, which varies greatly in different sea areas. The southern coast of Shandong Province entered the peak breeding season in the first half of May. However, in the waters of the northern island of Long Island, the breeding peak is only in June and July. In addition to water temperature, the change of gonad tree planting is also an important basis for determining the breeding season. When the gonad index reaches 15% on average, it enters the breeding season. During the breeding season, it has the habit of discharging many times. After the first discharge, it can be discharged in about a week, and the shelling is repeated many times. The amount of eggs laid increases with the increase of individuals. The height of the shell is 6-7cm, which is twice that of the second instar. The spawning amount is 8 million-10/00000, and the spawning amount is about 2 million at a time. The number of eggs laid by the third instar with a shell height of 8-9cm is150,000, and the number of eggs laid at one time is about 4 million. The mature egg is about 70 microns in diameter and the sperm is about 50 microns in length.

grow seedlings

The suitable density for larval culture is 8- 12 /mL, and the culture water temperature is 18-20℃. The fertilized eggs can be fed with Phaeodactylum tricornutum, Isochrysis tricornutum, Chrysophyta tricornutum, Chlorella, Sargassum and Platymonas when they hatch to the D-shaped larval stage. Taking Isochrysis globosa as an example, the initial daily food intake of D-shaped larvae is 1 0,000-10.5 million/ml; The daily food intake at the top of the shell is 1.5-50000/ml; Feed in 3-6 times. The mixed feeding effect of multiple baits is better than that of single bait. Change water twice a day. The light is generally controlled at 500lx. Pour the pool every 5-7 days. In seawater with high heavy metal content, 2-3g of disodium ethylenediamine tetraacetate (EDTA) is added per cubic meter of water. The attachment base is generally a small curtain made of brown rope (rope diameter is about 8mm) or polyethylene net. After adhesion, it needs to be treated with 0.5% sodium hydroxide to clean oil stains. After repeated hammering and soaking, debris, impurities and soluble harmful substances are removed. Putting the attachment base too early will not only affect the normal management of the nursery pond, but also be easily polluted by residual bait and impurities, which will make the water quality worse and make it difficult for larvae to attach. If the attachment base is put in too late, a large number of larvae will miss the best attachment opportunity and sink and die. The best release time should be when more than 50% larvae in the pond have eye spots, and generally cooperate with the inverted pond.

Key points of breeding

Raft culture: Build a raft frame in the sea area, and then hang a breeding cage on the raft frame. Among them, about 200 are controlled in the first floor of Yabei 1cm, and the stocking amount is115 hectares with 400 cages; Ear piercing and hanging culture: drill a small hole in the front ear of the young shellfish with a shell height of more than 3CM, and then hang it on the culture rope for culture; Bottom-sowing culture: shellfish fry are directly sown to the seabed or intertidal zone for culture, and can be mixed with prawns.

incubation time

Chlamys farreri is perennial, and 1-2-year-old shellfish grow faster. Under the condition of artificial raft culture, the shell height of the larvae cultured at room temperature in that year can reach more than 2cm before winter, and the shell bottom height can reach about 7cm in the following year.

economic value

High economic value. In addition to eating fresh shellfish in coastal areas all the year round, in order to keep fresh and facilitate transportation, most of them take out their adductor muscles and transport them around after freezing. This kind of shellfish is called frozen scallop column or frozen fresh shellfish. It is an important cooking material for high-class hotels and restaurants, and it is entering ordinary families. Scallop closed shell muscle dried product? Scallop It is one of the eight treasures of seafood.

Bay scallop

Argopecten irradians, also known as Argopecten irradians, belongs to Mollusca, Lamarck, Heteropoda and Scallopidae.

morphological character

The shell is fan-shaped, the two shells are almost equal, the rear ear is larger than the front ear, and there is a foot hole under the front ear. There are 18 radiation edges on the shell surface, and the shell surface is dark brown or brown. Native to the Atlantic coast of the United States, it is a local mollusk. Zhang Fusui was introduced to China from the United States in 1982. Bay scallop has the characteristics of strong adaptability, fast growth, short culture cycle and high yield. Its meat is delicious, rich in protein and vitamins, and has high nutritional value. As a high-quality mariculture variety, it can be harvested all year round and has good quality in spring.

Living habits

Bay scallops are mostly distributed at a depth of 3- 10 meters below the sea surface, and their personalities are pungent. The temperature range is-1-3 1℃, the growth stops below 5℃, the growth is slow below 10℃, and the growth is faster at 18-28℃. Its salt tolerance range is 16? -43? The suitable salt range is 2 1? -35? . When the environment is not suitable, the crural line can be cut by itself, and the two shells open and close to hit the water quickly. Bay scallop can jump about 1-2 meters once entering the water.

The average shell energy of bay scallop is above 5-6 cm, and the largest individual is about 7 cm after 8 months in high water and fertilizer sea area. The average shell height is only about 5 cm in the inner gulf current slow sea area. Under the condition of full artificial culture, low-density stocking grows faster than high-density stocking, and seedling separation is earlier than seedling separation.

Reproductive habit

Bay scallop is hermaphrodite. Its growth and development are rapid, and the seeds cultivated in spring will mature in autumn (the shell height is about 5 cm), which can be used to collect eggs for parent shellfish to cultivate seeds. The smallest size in biology is 2.2 cm. The gonad is confined to the abdomen, and the testis is located on the periphery of the abdomen, which is milky white when mature; The ovary is located inside the testis and is brownish red when it matures. There is usually a black membrane on the surface of gonad. During gonadal maturation, the black membrane gradually disappears, and the testis and ovary are distinct.

When the gonad begins to develop, a certain amount of bait is given under the condition of temperature control, which can promote the gonad to mature ahead of time and expel sperm eggs, which is the biological basis of early seedling and multi-crop seedling. In the northern waters of China, there are two reproductive peaks in spring and autumn, from late May to June in spring and from September to 10 in autumn. After the autumn reproductive period, the abdomen is transparent and there are no sperm eggs.

Comb shell

Native to Japan and Korea. It has been introduced into China for artificial propagation and proliferation in northern coastal areas such as Shandong and Liaoning.

characteristic

It belongs to filter-feeding bivalve shellfish. Its shell is fan-shaped, its right shell is prominent, yellow-white, its left shell is slightly flat, and its right shell is slightly smaller, which is purple-brown. There are 15-20 radial ribs on the shell surface, and shallow footline holes on both sides of the shell ear. The right shell rib is wide and low, and the rib is narrow; The ribs of the left shell are thinner and wider. There is a triangular internal ligament under the top of the shell. The natural distribution water depth is 6-60m, and the bottom material is gravel. Patinopecten yessoensis is a cold-water shellfish, and its growth temperature ranges from 5? 23℃。 Mainly produced in the southern waters of the Kuril Islands in Japan and Russia, Hokkaido in Japan and the northern part of the mainland. The suitable salinity range is 24-40, which is distributed in the coastal waters with high salinity, hard bottom without fresh water injection, less sediment and water depth less than 40m. It is mainly cultivated in Liaodong Peninsula in northern China and Long Island in Shandong. The growth rate is slow, from juvenile to shell height 1L- 12cm, and the shortest time is 1 year for 7 months. According to records, the maximum shell height can reach 27.94 cm and its life span is about 25 years. The breeding season of scallop Patinopecten yessoensis in northern China is 3? In April, the spawning temperature is 3? 10℃。 The ratio of male to female in natural population is about 6:4. The fertilized eggs of Patinopecten yessoensis continued to develop after fertilization in seawater, and the initial shell length of type D larvae was 1 10? 120? m； After the planktonic larval stage, the average shell length of larvae reaches 220? 240? M, eye spots appear, and then attach metamorphosis, and the larvae are as long as 3? 4cm, the foot silk gland degenerated.