Murray Cod: a treasure of Australia
The Murray cod, also known as the Australian cod and the Australian dragon spot, is a rare fish from the Murray-Darling River basin in Australia. Because of its special appearance and delicious taste, Moray cod is known as "national treasure fish" in Australia.
Moray cod meat is firm, tender, very few thorns between the muscles, with a very unique flavor. Combined with the relevant test results, it can be seen that Murray cod meat contains 7 amino acids and high unsaturated fatty acids (such as DHA, EPA), which are highly nutritious and economical evaluation.
Market situation: Hot ingredients in short supply
Moray cod enjoys a high reputation abroad, and is also loved by consumers in China, and the adult fish market is in short supply. At present, the price of Murray cod commodity fish in the wholesale market is close to that of high-end seawater fish, and some markets sell for 150 yuan a catty. The market is distributed in more than 30 cities, and the sales volume reaches 300-400 tons per year.
Introduction and technology exploration: suitable for high-density culture
Moray cod was first introduced into China in 2001, but it has been difficult to popularize in our country because of its supply of seedling. Due to the high age of Murray cod sexual maturity, low spawning amount and demanding breeding environment, traditional pond breeding has been adopted in China for a long time.
But for more than a decade, researchers have never stopped exploring the breeding technology of Moray cod. So far, the technology of large-scale artificial seedling rearing of Murray cod has been successful.
At the same time, Moray cod has the characteristics of strong disease resistance, large tolerance range to water temperature, high conversion rate of artificial compound feed (feed conversion rate is 1.05), etc., which is suitable for high-density culture, especially in factory circulating water culture.
According to research surveys, under proper temperature and good management, the Moray cod is raised from 2 grams to 500-1000 grams for about 10-12 months, and the weight of the fish raised for two years can exceed 2.5 kilograms. Conventional farming density is maintained at 100-200 kg per cubic meter of water, up to 320 kg.
The advantages of industrial recirculating aquaculture of Moray cod: high returns
Because of its unique advantages, the factory recirculating aquaculture technology has shown great potential and broad prospects in the aquaculture field of Moray cod:
1. Multiple batches/stable production:
The water quality of industrial recirculating aquaculture is stable and controllable, which provides guarantee for constant and stable production. Four seasons continuous multi-batch production, low comprehensive cost
2. High yield/High success rate:
Output per unit of water > 300 jin/m2; Clean water healthy breeding, the success rate of nearly 100%
3. High quality/food safety
No disease, zero drug residues, no resistance culture; BAP certified, secure and at a premium
4. Low consumption/zero emission:
Reducing water and land resource consumption; Zero sewage discharge, environmental protection full cycle farming
Breeding attention elements: to ensure the healthy growth of Moray cod
Because the Moray cod is a warm water fish, the growth water temperature is 18-25℃, the optimal water temperature is 21-24℃, 35℃ is the lethal water temperature of Moray cod, and the low temperature can be tolerated to 5℃.
pH is about 8.3; The dissolved oxygen is controlled at 7 ~ 10 mg/L; Ammonia nitrogen is lower than 0.3 mg/L; Nitrite lower than 0.05 mg/L; The salinity should be controlled in 0.5‰ ~ 5‰; The suspended matter in the water should be less than 10 mg/L.
In the recirculating aquaculture system, the content of ammonia nitrogen, nitrite and other harmful substances in water can be effectively reduced by means of timely discharge, physical filtration and biological treatment.
In terms of diseases, Moray cod fry are prone to ciliate and other protozoa infection of the gill, if the fry is found to rub the ground or pool wall, salt bath should be carried out, the salinity is 10‰, the salt bath time is 4-8 hours, and then the salt bath is reduced to 7-8‰ for 2-3 days, the salt bath should stop feeding and maintain good water quality the day before the salt bath.
The artificial compound feed with 50% protein content is the best for the growth of Moray cod, and the daily feeding amount is 2.5-3% of body weight. Feed once every six hours, and pay attention to controlling the feeding amount to avoid the occurrence of residual bait.
In addition, pay attention to the relationship between breeding density and fish, too low density will reduce the enthusiasm of fish to eat, resulting in food waste; Too high density will affect the growth of fish and even cause increased mortality, so it is necessary to reasonably control the breeding density.
New opportunity
China has a rich variety of farmed Marine fish, but the freshwater fish species are relatively simple and lack of precious fish species, and some high-grade freshwater fish species are urgently needed. Therefore, the arrival of Moray cod has not only greatly enriched the dining table of Chinese people, but also provided new opportunities for the breeding and supply of Moray cod with the introduction of factory recirculating aquaculture technology.