Man's needleless squid breeding status
Needleless squid, commonly known as cuttlefish, belongs to the mollusk phylum, cephalopods, decapods, squid family, and needleless squid genus. Although there have been extensive reports on the Needleless Squid, there have been fewer reports on its basic biological characteristics and breeding status. Therefore, through investigation, consultation of relevant literature and combined with my own summary of breeding work, the author summarizes the current situation and industrial development trend of Man's needleless squid breeding, providing reference for further optimizing breeding technology and accelerating industrial development, with a view to gradually repairing and revitalizing Man's needleless squid resources in China.
First, the current situation of breeding
In order to save the extinct Man's needleless squid, in the early 21st century, Wu Changwen's team of Zhejiang Ocean University took the lead in finding a small string of Man's needleless squid fertilized eggs in the eastern polar waters of Zhoushan Mountain through divers, and began the artificial breeding research of Man's needleless squid. Subsequently, Wang Chunlin's team at Ningbo University also began related research on the artificial breeding of Man's needleless squid. Around 2005, Man's needleless squid artificial breeding technology has made a comprehensive breakthrough, the relevant scientific research units have carried out breeding promotion experiments, while in the sea area of Zhoushan, Zhejiang Province began to carry out breeding and stocking experiments, due to the high cost of Man's needleless squid breeding, high mortality rate in the high temperature period, breeding economic benefits are not good, the current breeding promotion is more difficult, but because of the man's needleless squid has the characteristics of fast growth rate, short life cycle and reproductive migration, breeding and stocking back-catching has achieved remarkable results, It is an ideal breed for breeding and stocking. In 2013, with the advancement of the "East China Sea Fishery Restoration and Revitalization" plan in Zhejiang Province, the fishery authorities took man's needleless squid as the main breed of breeding and stocking in the East China Sea fishery, and the enhancement and stocking intensity was unprecedented. However, in Zhejiang, the research on Man's needleless squid mainly focuses on basic biology and small-scale artificial breeding, and most of the small-scale artificial breeding adopts the mode of harvesting wild squid as a breeding brood in spring, which has the characteristics of small production scale and unstable supply, and it is difficult to meet such a large demand for breeding and stocking. In view of this situation, zhejiang marine fisheries research institute in 2013 set up a man's needleless squid large-scale breeding project team, on the basis of the research of the predecessors, the use of indoor autumn selection of seeds, spring large-scale breeding technology model, to solve the bottleneck of large-scale artificial seedlings, standardize the breeding and stocking technology process, to achieve the annual production of Man's needleless squid fertilized eggs more than 50 million, has now become the largest production base of Man's needleless squid seedlings in Zhejiang Province and even the country. More than 100 million needleless squid eggs have been multiplied and stocked in zhejiang waters. According to the relevant survey and evaluation results, in 2013, the resources of Man's needleless squid in Zhejiang Province rebounded from the brink of extinction to 1500 tons, and reached the level of 3000 tons in 2016, and the output showed a momentum of increasing year by year, and the recovery was remarkable.
Second, the existing problems
1. Germplasm improvement In large-scale artificial seedlings, the update speed of Man's needleless squid is fast, and it can be cultivated for 2 seasons a year, and even up to 3 seasons. Generational intraspecific reproduction can easily lead to germplasm degradation, which is manifested as precocious puberty, small individuals, small spawning, and weak resistance. Therefore, wild squid broodstock or fertilized eggs must be purchased annually to supplement them into the conservation population for germplasm improvement.
2. Bran shrimp rely on production practice has proved that Man's needleless squid must be fed a large number of live bran shrimp before completely feeding small shrimp, otherwise the survival rate is greatly reduced. At present, the artificial compound feed for man's needleless squid larvae has not yet been developed, and the live bran shrimp is irreplaceable to the squid, and whether it can be sufficiently and stably supplied is the key to whether the large-scale seedlings of man's needleless squid can be attacked. There are too many influencing factors for the large-scale cultivation of live bran shrimp, and there is a large instability in the supply.
3. It is difficult to promote breeding At present, the research and development of Man's needleless squid full-price compound feed is not mature, and the seed production unit can only choose live (early stage) and chilled bait (later stage), the cost-output ratio is relatively low (about 1:1.3), and the low profit margin is the main reason why it is difficult to promote single culture in a large area. The author believes that Man's needleless squid is currently not suitable for breeding, and is more suitable for breeding.
4. Disease prevention and control is difficult Man's needleless squid is often due to food grabbing, biting frame (very easy to occur when splitting seedlings) and other behaviors caused body surface damage, and then easy to induce bacteria, fungi, Vibrio and other infections, at this time the common broad-spectrum antibacterial drugs are often not obvious effect, and commonly used water disinfectants are easy to cause squid ink spraying, causing secondary injury. Therefore, once mans needleless squid becomes ill, it is difficult to prevent and treat. In the large-scale breeding of seedlings, it is necessary to achieve fine management, such as maintaining clean water quality, hierarchical breeding, a small number of times when dividing the pond to prevent bites, reasonable feeding of bait and other measures, so as to achieve prevention.
Third, the outlook
1. Accelerate the research and development of Man's needleless squid full-price compound feed Accelerate the research and development of Man's needleless squid full-price compound feed, get rid of the dependence on live and chilled bait, not only can improve its large-scale breeding technology level, but also can reduce the cost of breeding, increase the breeding enthusiasm of Man's needleless squid.
2. Increase the research and development of man's needleless squid deep processing At present, the larger size of Man's needleless squid is not mature in transportation equipment and preservation technology, and can only be sold in a frozen manner when listed in batches, and the price is difficult to guarantee. Accelerate the research and development of man's needleless squid deep processing, so that the "whole body is treasure" Man's needleless squid can give full play to its own value, solve the backlog problem when the market is concentrated, generate greater added value, and bring better economic and social benefits.
3. Increase the breeding and stocking of Man's needleless squid As a good breeding and stocking species, the amount of resources has increased significantly through the breeding and stocking of Man's needleless squid, which is more significant than that of the large yellow croaker (2 to 3 years to reach sexual maturity) that is also one of the "four sea products". It is recommended that the fishery authorities continue to increase the breeding and stocking of man's needleless squid and the control of the fishing ban period, so that it can reach the level of self-reproduction and further restore and revitalize the fishery resources in the East China Sea.
