Management Methods and Technical Key Points for Introduced Snakehead Fry and Fingerlings

There are 3 sources of snakehead fry and fingerlings: first, artificial breeding; second, purchasing from other places or other units; third, catching wild fry and fingerlings in places with lush aquatic plants in reservoirs, lakes, and ditches. How to manage the latter two types of fry and fingerlings is described below:

1. Fry and fingerlings purchased from other places or other units

When purchasing fry and fingerlings, carefully select fish that are robust and of good quality. The specific standards are: from the external appearance of the fish, the scales and fin rays are required to be intact, the color bright and glossy, the body shape normal, and there is no external injury or disease. From the physique, a high degree of plumpness, lively swimming, and quick reactions are required. From the size, for the same batch of fry and fingerlings, uniform individuals and consistent size are required. Fry and fingerlings meeting these conditions can be considered good fry and fingerlings.

After purchasing the fry and fingerlings, before stocking, soak and disinfect the fish body with salt water or bleaching powder, and then put them into ponds or cages for rearing.

2. Captured wild fry and fingerlings

Every year from May to July is the breeding season of snakehead, with June being the peak. Therefore, according to their breeding habits, you can go to ditches, swamps, ponds, lakes, and shallow-water areas of reservoirs with lush aquatic plants to look for groups of snakehead fry and fingerlings. After discovering a group of snakehead, you can use 30-50 mesh nylon net cloth or polyethylene net cloth to make a semicircular catching net (fishermen call it a duanwang) for catching, or use the method of setting a maze trap to lure and capture them.

The maze trap is easy to set on flat pond bottoms in shallow-water areas, or to intercept at reservoir branches, lake branches, or ditch branches.

The maze trap is composed of stakes, foil (fish-blocking wall) walls, and a fish-collecting part. The stakes are bamboo poles or 14#-16# steel bars (coated with anti-rust agent), 1.5-2.0 m long, and the number varies depending on the length of the maze trap; generally 1 is inserted every 3-4 m. The foil walls are made of bamboo material and polyethylene fish fry netting, commonly called chuanzi. The height and length of the chuanzi depend on the depth of the water and the length of the interception. The fish-collecting part is a foil ring made from chuanzi, varying in size and shape, usually nested large and small to form a very complex maze; once fish are lured into the foil ring, they cannot escape. The final part of the fish-collecting section is sealed with rope; when collecting fish, untie it, pour the fish out, and then sieve and grade them.

When large-size fry and fingerlings of more than 10 cm are caught, after soaking and disinfecting with salt water or bleaching powder solution and then temporarily rearing them in a small pond or cage for another 10-15 days, they may be transferred to adult fish ponds for aquaculture. Small-size fry and fingerlings caught must be cultivated to the required size before they may be transferred to adult fish ponds for aquaculture.