Effective Measures to Increase Hatch Rates in Scallop Farming

Scallop is the collective name for bivalve mollusks of the genus Pecten, with over 400 species. More than 60 species in this family are among the important marine fishery resources around the world. The shell, meat and nacre have extremely high utility value. Many scallops are eaten as a delicacy. Scallops with bright colors and radial patterns are favored by collectors, and the patterns have been adopted as designs for artworks. Scallop is a family in the order Pterioida, subclass Pteriomorphia, class Bivalvia. It is widely distributed in seas around the world, with the greatest species richness in tropical seas. About 45 species have been found in China, among which the northern Chlamys farreri (Zhikong scallop) and the southern Mimachlamys nobilis (noble scallop) and Amusium pleuronectes (Asian moon scallop) are important commercial species. Scallop, also known as sea fan, has delicious meat and rich nutrition. Its adductor muscle, after being dried, is the “dried scallop”, which is listed as one of the Eight Treasures. How to increase the hatch rate in scallop farming troubles many aquaculture farmers, so we provide some information for farmers' reference.

I. Selection and overwintering of broodstock

1. Select broodstock with plump gonads, large individuals and intact appearance. After the broodstock are brought into the workshop, stabilize them for 2 days first, with water temperature at natural water temperature (3°C), and temporary holding density of 90 individuals/cubic m to 100 individuals/cubic m.

2. Indoor overwintering is recommended, changing 1/3 or 1/2 of the natural seawater daily, and siphoning the sediment once every 5 days to 6 days.

II. Temporary holding of broodstock to maintain ripeness

The cultivation of broodstock is the foundation; the degree of maturity of broodstock gonad development directly affects the quality of the eggs obtained.

1. Pay attention to raising the effective temperature and control the rate of water temperature increase. In the early stage, raise the water temperature by 1°C per day, hold stable for 3 days when it reaches 15°C, then raise it by 0.5°C per day, and wait for spawning when it reaches 19°C.

2. Pay attention to improving ammonia nitrogen content and dissolved oxygen in the water. Adopt the method of transferring the broodstock between tanks and changing water. In the early stage, transfer the broodstock once per day; after the water temperature reaches 16°C, adopt the method of continuous flow-through water and frequent siphoning to improve water quality, with the water exchange volume reaching one full volume per day, while providing slight aeration every day.

3. Pay attention to the nutritional combination of feed so that yolk accumulation reaches a certain amount. The feed is mainly fresh diatoms, supplemented by golden algae and substitute feeds (such as starch, egg yolk, spirulina powder). In the early stage, the daily feeding amount is 50,000 cells/mL water to 200,000 cells/mL water; after 14°C, food intake increases, and the daily feeding amount is 200,000 cells/mL water to 400,000 cells/mL water, fed in 8 to 12 portions.