The method of shrimp culture using gei wai was introduced into Hong Kong in the mid 1940's. Gei wai is basically a shallow water shrimp pond surrounded by bunds, which were constructed with a rock and grit centre covered with mud dug on-site. Gei wai is mainly used for culture shrimp, fish, oyster, algae and brackish sedges, with "gei wai shrimp" an already-renowned delicacy. Now only several gei wais remain in the Mai Po Marshes Nature Reserve managed for education purpose.

Fishermen brought into gei wai sea water containing juvenile shrimps and fishes. They controlled the influx of tidal water by the slice gates. Shrimps and fishes inside gei wai feed on organic matter from fallen leaves of mangroves, or benthos organisms in the gei wai. During harvesting time, fishermen drained the gei wai to collect gei wai shrimps and fishes. Creatures with little economic values are left behind and become food for birds and other animals.

The AFCD Staff is demonstrating the
operation of gei wai.
After harvesting, fishes and shrimps
remaining in the ponds become
delicacies for birds.