Introduction, breeding and breeding of Australian gem perch
Jade perch, also known as gem spot, gem fish, jade perch, jade, etc., scientific name scortum bacoo, taxonomy belongs to the order Perciformes, the family Theraponidae, scortum. The species of the family Echinaceae are distributed in seawater and freshwater, and the existing species in China are all marine habitats, which are distributed in the southern coastal provinces and regions of China. The gem perch is native to Australia's Aier Lake, Bro-Bencaina water system, is one of the most prestigious freshwater fish in Australia, it was first evolved from marine fish, so it can maintain the tenderness of freshwater fish, but also has the unique deliciousness of marine fish, favored by the majority of consumers. The Gem Perch was developed in the 1990s by the Victoria Freshwater Fish Resource Centre in Australia as a new species of cultured fish. In June 2001, Qingdao Modern Agricultural Development Center introduced 5-6 cm gem perch fingerlings from Melbourne, Australia, for trial breeding of commercial fish; in 2002, the Tianjin Jinnan Special Aquatic Fry Breeding Base of the National Agricultural Science and Technology Park also carried out the introduction of gem perch, and the two introduction units have achieved certain success in the basic biological characteristics, breeding technology and nutrition research of gem perch. Experiments have proved that gem perch can be farmed in most parts of China.
First, the basic overview
1. External morphological characteristics
The body of the gem perch is spindle-shaped, thick and flattened, with a small head, a mouth end, a gradual arch on the back of the head, and a large and rounded abdomen. On one or both sides of the fish body there are 1 to 2 or more black crystal oval patches and scattered small patches, just like the fish body is inlaid with beautiful black gems, and the shape is extremely beautiful. The gem perch is scaled with a short and wide caudal fin and slightly concave. The lateral lines are clear and extend back along the center of the body to a more straight. The dorsal fin consists of two parts, hard spines and fin strips, with several spines at the edge of the posterior gill cap, and the body length is 2.5 times the body width. The gem perch is pale blue-grey , with a white belly and grayish-brown fins. The upper and lower jaws are densely packed with small canine teeth.
2. Internal morphological characteristics
The stomach of the gem perch is developed in a "Y" shape, and the pyloric blind sac is petal-like and spreads out in 20 to 24 pieces. The length of the intestinal duct is 3 to 4 times the body length. The entire abdominal cavity is almost filled with white fat blocks, which weigh up to about 11% of the body weight. The gonads cling to the ventral surface of the swim bladder, the ovaries are flattened and banded, pink, and the sperm nest is thinly banded, thickening and growing with ontology, and is cloudy white.
3. Biological characteristics
Gem perch is a warm water fish, the temperature range of 10 ~ 40 ° C, water temperature below 20 ° C or even below 15 ° C when the activity ability and feeding ability is basically normal, but the growth rate is slower, the temperature is lower than 10 ° C that is, death occurs, suitable for breeding in the southern region of China, winter should do a good job of overwintering measures, its wintering requirements and tilapia, leather bearded catfish and freshwater white pomfret have many similarities, where it can be suitable for tilapia wintering places are basically suitable for gem perch. In May every year, when the water temperature rises above 18 °C, it is suitable for seeding, and the water temperature above 25 °C can be laid by artificial injection of oxytocin, the eggs are floating, the egg diameter is small, and the study results show that the most suitable incubation water temperature is 28 °C. The gem perch is active, swims quickly, and prefers to live in the middle and upper layers of water. In the natural waters, the gem perch is an omnivorous fish, mostly feeding on small crustaceans, small fish, water earthworms, red worms, locusts, bread worms, etc., as well as algae and organic detritus. Under artificial breeding conditions, granular mixed bait can be fed, floating bait should be used, animal protein content is more than 36%, and the particle size of the feed is determined according to the specifications of gem perch, generally 1-3mm. Juveniles and adults can be fed pellet bait of different particle sizes, depending on the water temperature, body weight and feeding conditions.
Second, the artificial breeding of Australian gem perch in China
1. The introduction of the Australian gem perch
In June 2001, Shenghua Seed Co., Ltd., a subsidiary of Qingdao Modern Agricultural Development Center, took the lead in introducing more than 90,000 gem perch species of 5-6 cm from Melbourne, Australia, with a transport survival rate of more than 95%, and carried out trial culture of commercial fish, achieving initial success in introduction. In the summer of 2002, the seed was introduced in batches again, and pond culture and reservoir cage culture were carried out separately, both of which were successfully tested.
In 2002, the Tianjin Jinnan Special Aquatic Seed Breeding Base of the National Agricultural Science and Technology Park also carried out the introduction experiment of gem perch, which was also successful.
From 2002 to 2003, Zhejiang Xinchang County Zhejiang East Modern Aquatic Products Development Co., Ltd. has introduced 550,000 gem perch fry, in the closed cycle aquaculture system for high-density fry breeding tests, feed for Shanghai Unified Feed Company production of full-price seawater giant yellow croaker sedimentary granule artificial compound feed, daily bait volume of 2% to 6%, aquaculture pond water temperature maintained at 21 ~ 25 °C, dissolved oxygen 5 ~ 8 mg / L, pH value of 6.5 ~ 7.5, after 92 days of breeding gem perch seed survival rate of 92.64%, the average tail weight increase of 44.6g, the system fish load of 55kg/m3, to achieve a yield of 55kg per cubic meter of water body.
2. Artificial breeding of Australian gem perch
In October 2003, the Fisheries Science Research Institute of Putian City, Fujian Province, purchased adult fish with an average weight of 550g from Qingdao Shenghua Seedling Co., Ltd., with an adult survival rate of nearly 100%, and bred them in its development base until June 2004. Broodstock breeding pond is a square cement tank, the area is 81m2, the depth of the pool is 1m, the water depth is maintained at 60 to 70cm, the pond stocks about 100 broodstock, the ratio of male to female is 2:1, and the aeration system is installed in the pond. Broodstock rearing water is from underground wells at a depth of about 10 m. The bait is prepared for itself in a powdery form with a protein content of about 40%. Feed twice a day, at 5:00 in the morning and at 5:30 in the afternoon. The powdered bait is processed into granular bait before feeding. The bait rate is controlled within 5%, and it increases or decreases at any time with the weather, water temperature, fish activity, etc. Broodstock with gonad maturity were first acquired in culture until June 2005. In June 2005 and June 2006, four trials of artificial seedlings of gem sea bass were successfully carried out, and a total of 22 female broodstock were induced, and the injection of oxytocin was twice, with an interval of 6 to 8 hours between injections. The first female was injected with LRH-A at a dose of 0.5 μg/kg of fish, and the males were not injected; the second time the females and males were injected with highly effective oxytocin at a dose of 2,000 IU/kg of fish bodies. 1.18 million fertilized eggs were obtained by natural spawning methods, and the eggs were collected and counted and placed in the fry hatching ring for flowing water hatching. 750 000 fry are bred. During this period, a total of 435,000 fry of more than 3 cm were cultivated, and on July 15, 2005, 5,000 fingerlings with a body length of 3 to 5 cm were cultivated in the nursery test and put into a pond with an area of about 2000 m2 in the field for the grow-out test and the natural overwintering test of the wild pond, and by July 2006, the adult fish with an average size of 750 g/tail above 3.56 t were raised, with significant economic benefits.
In May 2004, Xianheng Aquatic Agriculture Co., Ltd., Nanhai District, Foshan City, Guangdong Province, began artificial breeding of gem perch, and in June 2005, more than 1 million seedlings were produced through artificial breeding, and the seedlings reached 500g/tail by mid-October. In April 2006, artificial breeding was carried out again, and the fry could be produced on demand, and millions of fry were already cultivated in ponds that year.
3. Adult culture of Australian gem perch
In 2004, The Hangzhou Aquatic Technology Extension Station and the Fuyang Aquatic Service Station conducted the australian gem perch breeding experiment at the aquaculture base of Fuyang Lingqiao Town, and achieved good production and economic benefits. Ponds are divided into special ponds and polyculture ponds, with an area of 2.8 mu and a water depth of 1.8m, and a polyculture pond area of 1.5 mu and a water depth of 1.5 m. The water source is The water of the Fuchun River, the water quality is fresh, pollution-free, the amount of water is sufficient, and it meets the standard of GB11607. The stocking time is June 17, 2004, of which the number of stocking ponds is 2500, and 893 are per mu, with a specification of 50g/tail. The polyculture pond is mainly based on the cultivation of Penaeus vannamei, according to the conventional stocking and management, 600 gem perch species are cultured, 400 per mu are placed, and the size is 50g/tail. Fish species are bathed in salt water before entering the pond. The captive pond was harvested on 20 October 2004, and the average size of adult fish reached 450 g/tail, the total yield reached 1113.7 kg, the average yield reached 397.8 kg per mu, and the survival rate reached 99.0%. The polyculture pond was started on October 8, 2004, and the average size of gem perch reached 600 g/tail, the total yield reached 352.8 kg, the average yield reached 235.2 kg per mu, and the survival rate reached 98%; the catch yield of Penaeus vannamei in South America was 450 kg, and the average yield per mu reached 300 kg
From June 11, 2006 to June 26, 2006, the Intensive Intermediate Breeding Experiment of Australian Gem Perch seed was carried out by chenzhou institute of agricultural sciences in Hunan Province and Chenzhou Golden Coast Ecological Fishery Co., Ltd. in Hunan Province, with a total of 30,000 seedlings, of which 10,000 were each with an average body length of 45 mm and a weight of 1.6 g, and the average length of 20,000 tails was 35 mm and the weight was 0.8 g. The experiment is carried out in a fully enclosed factory plant, the whole system adopts the Australian patented design and construction, with artificial temperature control, oxygenation, biological filtration, automatic water circulation and other functions, the experiment is carried out in the isolation breeding system and the cage culture system, divided into two stages: isolated culture and cage breeding. The isolated culture tank has a diameter of 1.5 m, a height of 75 cm, and an effective volume of 0.8m 3. Cage size 1 m× 1 m × 1 m, placed in the main pond culture water. The feed is made of marine fish floating compound feed, and the crude protein content ≥ 43%. With the increasingly obvious differences in the size and specifications of gem perch, they are graded every 5 to 6 days and placed in different cages according to the size of the fish body. When the fry body length reaches more than 70 mm, the intermediate breeding of the fry is completed. After 10 days of cultivation, the average body length of 45 mm per fry was 72 mm, the average weight was increased from 1.6 g to 11.8 g, the daily weight was 1.02 g, and the survival rate was 75.3%; the average body length of 35 mm per fry was 73 mm after 15 days of cultivation, the average weight was increased from 0.8 g to 12.4 g, the daily weight increase was 0.77 g, and the survival rate was 87.1%.
Third, the application prospects of Australian gem perch
Trial culture proved that gem perch has the advantages of fast growth, strong disease resistance, low oxygen resistance, easy transportation, easy fishing, and high population yield, and can be cultivated in indoor cement ponds with high density, outdoor pond single culture, and reservoir cage culture. It is very similar to the temperature requirements of tilapia and freshwater white pomfret, and is a warm-loving fish that is not tolerant to low temperatures, but its meat quality, nutritional value and economic benefits are much higher than those of the above fish. Gem perch head-to-tail ratio is small, tender flesh, less intermuscular spines, no fishy odor, back muscle hypertrophy, fish meat ratio of up to 58%, of which the protein content is as high as 18.9%, and rich in essential amino acids, fish meat and fish oil are rich in highly unsaturated fatty acids, especially known as brain gold "DHA" and prevent arteriosclerosis and "EPA" content are greatly more than the yellow croaker and other valuable fish.
Experiments have proved that gem perch can be cultivated in most parts of China, is a warm water fish, suitable for growing water temperature of 10 ~ 40 °C, the best growing water temperature is 21 ~ 28 °C, the water temperature drops to 17 ~ 18 °C when the feeding intensity is weakened, 10 ~ 15 ° C when the slow action or stationary in the middle and lower layers of the water, pH value of 5.5 ~ 8.5, dissolved oxygen requirements of more than 2.5mg / L, factory breeding requirements of 3.5mg / L or more, factory culture of gem perch to avoid strong light irradiation, Moving to outdoor ponds requires the necessary shading. Gem perch is very sensitive to copper sulfate and ferrous sulfate, so use with caution.
Any area with factory waste heat, underground hot water and other resources can be used to produce and breed seedlings, especially the existing farm of cultured tilapia with water resources and facilities conditions, which can be used to breed gem perch without modification or slight transformation. Outdoors, when the water temperature rises to 20 °C, the stocking size of about 100g of fish fingerlings, stocking density is reasonable, careful feeding of reasonable formula of granular bait, generally after 4 to 5 months of feeding, to the beginning of October can reach 500g / tail of commercial fish standards, its breeding efficiency is 3 to 5 times that of conventional fish.