CATDOLL : CATDOLL: Do you know what kind of fish is used in this dish?

Do you know what kind of fish is used in this dish?

Osmanthus fish

Osmanthus fish, family Siniperca genus. The body is relatively high and laterally flattened, with a bulging back. The mouth is large, and the lower jaw is significantly longer than the upper jaw. There are small teeth of varying sizes on the upper and lower jaws, the vomer, and the operculum. The rear edge of the preoperculum is serrated, with 4 large spines on the lower edge; the rear edge of the postoperculum has 2 large spines. The head has scales, and the scales are small; the lateral line bends upward along the dorsal arc. The dorsal fin is divided into two parts, connected to each other, with hard spines in the front and soft fin rays in the back. The body is yellow-green, the abdomen is grayish white, and there are irregular dark brown spots and patches on the sides of the body; there is a narrow black stripe from the tip of the snout through the eye socket to the front and bottom of the dorsal fin.

The scientific name of the red ladyfish is shortfin red ladyfish (Melodon H family). It is distributed in the western North Pacific Ocean. In China, it is produced in the East China Sea, Yellow Sea and Bohai Sea.

As shown in the picture, the specific type of snapper is unknown.

Lutjanidae Lutjanus

The picture below shows the silver snapper Lutjanus argentimaculatus (purple snapper), commonly known as the red snapper

The body is oval in shape, with blunt dorsal and ventral margins, and the dorsal margin is slightly curved. The distance between the two eyes is flat. There are fine sharp teeth on both sides of the upper jaw, the body is covered with medium-large ctenoid scales, and the cheeks and gill covers have multiple rows of scales; the base of the dorsal fin, anal fin and caudal fin is mostly covered with fine scales; the lateral line is complete, with 44 to 48 rows of lateral line scales; the body color ranges from gray to purple-red, with a silvery color and no obvious lines or spots on the body; its characteristic is that the snout is long and the scales above the lateral line are parallel to the dorsal margin in the front half of the body, and obliquely to the dorsal margin below the dorsal fin ray; the scales below the lateral line are parallel to the fish body axis. The color of each fin is the same as the body color; the dorsal fin has 10 hard spines and 13 to 14 soft rays; the anal fin has 3 hard spines and 8 soft rays; the pectoral fins are long and slightly equal to the head length; the caudal fin is truncated. Juveniles have several blue stripes on the cheeks. The body length can reach 120 cm.

They prefer to spawn in the turbid and deep outer reef areas or the outer edge of the reef. Their spawning period is in late spring and early summer. They are carnivorous and feed on other fish and crustaceans. They are distributed in the Indian and Western Pacific Oceans.

Reproductive characteristics of purple snapper

The breeding population of purple snapper has an incomplete sex conversion phenomenon of male first and female later. All the fish aged 1 and 2 are male, with a gonadal maturity index (GSI) of 2.07%-4.85%; 80% of the broodstock at the age of 3 are male, and 20% are transformed into hermaphrodites; the sex conversion of broodstock at the age of 4 is basically determined, and most of the broodstock are purely male fish with reproductive functions, while only about 30% of the female fish have obvious female primary sexual characteristics in the gonads of hermaphroditic broodstock; the gonadal GSI of hermaphroditic broodstock is 4.12%-8.09%, of which the ovarian GSI is less than 2%, and the 4-year-old female fish can carry about 700,000 to 1 million eggs; the oocytes of purple snapper develop asynchronously, and can spawn multiple times in a reproductive season. The results of the experiment show that multiple injections of low-dose LHRH A2 (3μg・kg-1) can effectively promote gonad development, gradual maturation, and eventually spawning, but it has no obvious induction effect on the ovaries of broodstock with egg diameters less than 300μm. Under the action of two different doses of mixed hormones, 5μgLHRH A2+1000I UHCG・kg-1 or 5μgLHRH A2+500IUHCG・kg-1, the gonads of broodstock can quickly develop and mature, and can naturally spawn and fertilize in small-scale circulating spawning ponds. In spawning ponds with a water temperature of 26.0-29.5℃, the hormone effect time is 35-43h. The mixed hormone of LHRH A2 and HCG has a good effect on maturation and induction of oocytes of purple snapper broodstock with an oocyte diameter of more than 400μm, and the induction rate reaches 100%.