What methods are there for identifying the quality of giant salamander seedlings?
The giant salamander is commonly known as the baby fish. Because giant salamander seedlings are relatively expensive, many prospective farmers worry about seedling problems. In particular, the current giant salamander seedling market is not well regulated, and driven by high profits, some people deceive farmers with non-giant-salamander seedlings such as small salamanders. Therefore, mastering the techniques for identifying the quality of giant salamander seedlings is of great significance to the success of giant salamander farming and to improving farming efficiency. Based on many years of practical experience in artificial breeding and seedling cultivation of giant salamanders, the author offers some views on the external morphology, external reactions, size and other aspects of giant salamander seedlings.
Basic external morphological characteristics of the giant salamander
The basic morphology of the giant salamander is as follows: for one-year-old juvenile salamanders that have not yet lost their gills, good quality is shown by external gills that are dark red or the same as the normal body color, and with no damage. If seedlings with damaged external gills are found, they are prone to bacterial infection and difficult to keep alive. For high-quality giant salamanders over 1 year old, the requirements are: no external damage and no deformity. However, attention must be paid to distinguishing them from several other morphologically similar caudate species. Table 1 lists their morphological identification methods.
External reactions
When stirred by hand, the limbs of giant salamander seedlings crawl vigorously on the bottom, and the tail swings quickly in the water. After draining the water and letting them crawl in a basin, those that move agilely are high-quality salamander seedlings.
Size
Look at the uniformity of the salamander seedlings. Whether the same batch of seedlings grows uniformly and those of similar size can be preliminarily judged as relatively good quality, while weak and small seedlings appear smaller than the rest of the same batch. In particular, giant salamander seedlings with relatively long heads grow slowly and should not be selected. Those with thick and strong trunks are better, but it is necessary to distinguish whether they have conditions such as abdominal bloating or ascites.
Observe whether there are signs of disease
Some giant salamander seedlings become infected with diseases due to poor feeding and management, which affects their quality. The specific observation method is: the limbs of the giant salamander are not swollen, the abdomen is not swollen or bloated with gas (abdominal bloating indicates ascites disease), gill-less juvenile salamanders (1 to 10 months old) have 3 complete pairs of gill filaments, there is no water mold parasitizing the gills, there are no white spots on the body surface, and the body shape is not too thin. Seedlings with these characteristics can be preliminarily judged as high-quality seedlings.
The quality identification of giant salamander seedlings should comprehensively consider the above factors. In addition, the feeding level and rearing conditions of the seedling supplier should also be considered. Based on seedling cultivation experience, it is recommended that farmers purchase giant salamander seedlings of about 50 to 250 g for rearing, as this makes it easier to identify quality and the survival rate can be as high as 100%.