Morphology and habits of Boleophthalmus punctatus

Mudskippers are the general name of Mudskippers, commonly known as jumping sharks, elastic paste fish, jumping fish and so on. It is a warm-water and warm-temperature coastal small fish, widely distributed in the west coast of Africa, India, Pacific waters, tropical and subtropical coastal shallow waters of the New Hebrides Islands (not produced in America), and distributed along the coast of China. There are not many species of mudskippers, mainly 3 genera and 6 species along the coast of China. There are 3 genera and 4 species in Zhejiang coast, which are Mudskippers, Big Mudskippers, Green Mudskippers and Big Green Mudskippers respectively. Mudskippers is a small edible fish with delicious meat taste, short food chain, low breeding cost, low investment cost, few fish diseases, easy cultivation, long-distance transportation resistance, rich nutrition and nourishing function. It is widely regarded as a good supplement by the masses in Zhejiang, Fujian, Taiwan and Guangdong, and has a large demand at home and abroad. The great mudskippers are the most important species in pelagic culture.

1. Morphological characteristics of the big mudskipper

Boleophthalms pectinirostris (Linnaeus), elongated body, nearly cylindrical in front, flat tail, flat dorsal and ventral margins. The head is medium and slightly flat. The nose is short and blunt, larger than the eyes. Eyes high, close to each other, protruding from the back of the head, lower eyelids free, eyes spaced quite narrow, like a longitudinal groove. Large mouth, subterminal position, flat cleft, long maxilla, maxilla extending below posterior edge of eye. Two jaw teeth are single, maxillary teeth are fine, with 2~4 canine teeth in front, mandibular teeth are large, horizontal, tooth ends are obliquely truncated, and there is a pair of canine teeth at the meeting place. The vomer, palate and tongue are toothless. The tongue is large and thick, rounded and not free. The upper lip fold is developed, almost reaches the center, the lower lip fold is short, is located in the mouth opening medium big, the operculum membrane connects in the isthmus, the isthmus is wide, the gill tip is short.

Body and head with round scales, small anterior scales, large posterior scales, pectoral fin base also with fine round scales, no lateral line.

Dorsal fin 2, the first dorsal fin is high, fin spine filiform extension; second dorsal fin is low, base extension, fin end extends beyond caudal fin base. The upper fin is long and slightly pointed; the lower fin is long and slightly pointed; the lower fin is formed into a sucker with a complete edge; the caudal fin is rounded. Dorsal greenish brown, ventral light-colored, first dorsal fin dark blue with irregular white dots; second dorsal fin blue with 4 longitudinal small white spots, arm fins, pectoral fins and ventral fins light gray, caudal fin greenish black, sometimes with white dots.

II. Living habits

(i) Habits

Mudskippers can use their pectoral and caudal fins to crawl or jump on water, sand and rocks. The large mudskippers can be fed with internal gills, skin and tail as respiratory aids. As long as the body is wet, it can live above the water for a long time. It is a warm-water eurythermal, euryhaline fish. Mudskippers can die if they remain in fresh water for more than ten days. Water temperature 14~30°C faster growth, 14°C below the cave seclusion, less food demand, slow growth.

Mudskippers have a stronger tolerance to water quality than ordinary fish in harsh environments. They have the same habits as freshwater@#@236 @#@. They can drill into holes to inhabit. Many holes can be seen scattered in the beach. General duct must have more than 2 orifices, one is the orifice, the other is the rear orifice (commonly known as the rear bubble) is the orifice for access to the main road, the rear orifice is smooth flow and air circulation. The cave channels are irregular and often Y-shaped or U-shaped. The depth and length of the channels vary according to the nature of the substrate. The mud is coated with a deeper depth, up to 50 - 70 cm. Holes are generally exclusive. But in the breeding season there is often hermaphroditism. The holes in mudskippers are also used as spawning chambers.

(2) Feeding Habits of Mudskippers gigas

Mudskippers live in coastal areas and estuarine tidal flats below the high tide zone. In sunny days, they jump out of their burrows to feed on mudflats, feeding on benthic algae, small insects and other small organisms on tidal flats. The results of stomach contents analysis showed that mudskippers mainly feed on attached diatoms. At low tide or at the bottom of drained pool water, it is often seen that mudskippers feed on benthic algae, that is, their lower jaws touch the beach surface, like ploughing fields, and they move their heads left and right to feed on benthic algae. Mudskippers do not eat each other's bad habits, artificial breeding more fertilizer to cultivate basic bait, promote the growth of mudskippers.

3) reproduction and growth

The sexually mature individuals are 12~15 cm, weighing 30~40 g. The breeding season is from April to September and the peak period is from May to July. Natural spawning in beach burrows, ovulating in them, buried fertilized eggs, hatching naturally. Sexual maturity when the female genital pore red, large and round; male genital pore narrow, elongated pointed. Ovary is yellow, the egg that gives birth sinks stickiness, ball shape, flaxen, transparent. The female has 1~ 25,000 eggs. One end of the egg membrane has a cluster of adhesive filaments, which can attach to other objects. The egg diameter is 0.51~0.61 mm. The fertilized egg hatches at the temperature of 26.5~29.0°C and the salinity of 25‰~27‰. The larvae can grow to 13 mm after one month. Male fish seminal vesicles 2, in the abdomen side was pale red thin strip shape.

The mudskippers grow very fast, and the early larvae can grow to 12~13 cm in the same year in areas with good environmental conditions and abundant benthic algae, reaching commercial specifications. Generally, after two years, it can also reach the commodity specifications. The average life span of mudskippers is 3 - 5 years, with the highest being 7 years.