Which aquatic plants are suitable for planting in crab ponds?

As the saying goes, "The size of the crab depends on the aquatic plants." River crabs like to live in ecological environments with abundant aquatic plants, fresh water quality, sufficient dissolved oxygen and rich biological bait. Production practice has proved that the quality of aquatic plant planting is closely related to the effect of river crab farming, so aquatic plant cultivation technology is also one of the key technologies for the success or failure of river crab farming.

The role of planting aquatic plants in crab ponds: aquatic plants are one of the important sources of bait for river crabs; aquatic plants are an indispensable place for river crabs to inhabit, hide, molt, and take shade and rest; aquatic plants can purify and stabilize water quality and improve the bottom sediment, while also stabilizing river crab settlement and reducing escape.

Among the types of aquatic plants planted in crab ponds, those commonly seen in production at present include Hydrilla verticillata, Elodea nuttallii, Vallisneria natans, Alternanthera philoxeroides, and so on. Various aquatic plants have their own different characteristics. For example, Hydrilla verticillata is tolerant of high temperatures, favored by crabs, grows quickly, and has strong regeneration ability (after being pinched off by river crabs, it can take root at each node). Hydrilla verticillata has tender leaves and little cellulose, and is the best plant-based bait for river crabs. Elodea nuttallii also has characteristics such as strong adaptability, high yield, and being favored by river crabs. At the same time, Elodea nuttallii does not rot in winter and stays green throughout the four seasons. Moreover, compared with Vallisneria natans and Hydrilla verticillata, Elodea nuttallii has significantly higher nutritional components, strongly absorbs nitrogen and phosphorus, and has a good water purification effect. The disadvantage of Elodea nuttallii is that it is not tolerant of high temperatures; when the water temperature remains above 30°C for a long time, it is prone to rotting. Vallisneria natans, also called flat-pole grass and noodle grass, is a typical submerged plant and is also one of the high-quality aquatic plants favored by river crabs. Ponds planted with Vallisneria natans must remove the residual grass floating on the water surface every day to prevent it from rotting and deteriorating water quality and affecting the photosynthesis of the aquatic plants at the bottom of the pond. Alternanthera philoxeroides (alligator weed) is a semi-aquatic and terrestrial plant with especially strong vitality, fast branching, and many fibrous roots. It is also an aquatic plant favored by river crabs and is currently one of the most planted aquatic plants in crab ponds in the Chongming area; the disadvantage of Alternanthera philoxeroides is that because its vitality and reproductive capacity are too strong, improper management can easily cause poor water color and deterioration of water quality, and the body color of river crabs living in ponds with Alternanthera philoxeroides is not as good as that of river crabs in ponds planted with Elodea nuttallii, Hydrilla verticillata and Vallisneria natans. In short, farmers can, according to actual conditions, plant multiple varieties of aquatic plants scientifically and reasonably, so as to give play to the advantages and roles of different aquatic plants.