Detailed Explanation of Efficient Rearing Techniques for Market Bullfrogs

The rearing of market frogs refers to the process of raising metamorphosed juvenile frogs into market frogs. It is the final stage of the entire bullfrog farming process and the most critical production procedure determining success or failure. At present, market frog farming can be divided into intensive rearing and extensive rearing. Extensive rearing involves enclosing a relatively spacious area with escape-prevention facilities, where juvenile bullfrogs are placed in this natural environment to feed on natural bait and grow naturally, and are harvested and sold once they reach market size. Intensive rearing, on the other hand, requires digging smaller artificial ponds, using artificial feeding, and conducting high-density fully artificial farming. This farming method yields high production and survival rates and is currently the more commonly adopted approach. The following focuses on this farming method.

(1) Construction of Rearing Sites

(1) Frog rearing ponds. For market frog farming ponds, earthen ponds are generally dug. To save farmland and costs, ponds, lotus ponds and small water collection pools can be slightly modified and renovated for this purpose. The location should be chosen in flat terrain with abundant water sources, with an area of 100 sq m to 300 sq m, a pond depth of 0.8 m to 1 m, and a water storage capacity of 30 cm to 40 cm. The earthen pond must be surrounded by netting to prevent frogs from escaping. For high-yield intensive farming, specially built cement ponds can also be constructed, with an area of 15 sq m to 30 sq m. The pond depth is 1 m, and the water storage depends on the size of the frogs. It is made of poured concrete, with the pond bottom and walls smoothed with cement. The slope of the pond bottom should be steep to ensure that one end has deeper water, which is the main habitat for frogs, and the other end has shallower water, often exposing the pond bottom so that frogs can come here to feed and rest. The pond bottom should also slope toward the drainage outlet to ensure the pond water can be drained completely. To prevent frogs from escaping, the top of the surrounding pond walls should be poured or built with an inward-facing 10 cm ledge. Cement ponds have high yields. Currently in China, 15 kg of frogs can be produced per sq m, suitable for intensive high-yield frog farming.

(2) Micro-environment of frog rearing ponds. To ensure good growth and development of bullfrogs, a favorable ecological environment should be created for them. Some aquatic plants such as lotus, arrowhead and calamus can be planted in the frog pond, which is suitable for bullfrogs to inhabit. Flowers, grass and shrubs should be planted on the land and slopes within the frog pond to facilitate bullfrogs to rest here and to attract insects as frog bait. To prevent the impact of high summer temperatures on bullfrogs, a half-pond shade shelter should be built on the south bank of the frog pond in spring, and some climbing plants such as pumpkin, loofah and grape should be planted to climb onto the shade shelter, allowing bullfrogs to come here to rest during the hot season. Through such arrangements, the ecological environment of the entire frog pond is made more suitable for the life and growth of bullfrogs.

(3) Cleaning and disinfection of frog rearing ponds. Newly built cement ponds should be filled with water and soaked for 15 days for dealkalization before use. When stocking juvenile frogs, the old water should be drained and replaced with fresh water before stocking. For earthen ponds, if newly dug, they should also be filled with water and soaked for 5 to 7 days before use to remove excess heavy metal salts. Cement ponds should also be coated and scrubbed on the bottom and walls with bleaching powder at a concentration of 1 mg per liter or quicklime solution at a concentration of 20 mg per liter for disinfection before stocking. For earthen ponds, 90 g to 110 g of quicklime per sq m or 7.5 g to 15 g of bleaching powder dissolved in water should be splashed for disinfection.

(2) Stocking, Bait and Rearing Management of Juvenile Frogs

The stocking density of juvenile frogs should be determined by various factors such as frog size, bait conditions and rearing management level. Earthen ponds generally stock newly metamorphosed juvenile frogs (4 g to 5 g) at 100 to 120 per sq m; cement ponds can increase the stocking density by 1 to 2 times.