Transfer technology for rearing percid juveniles in pond culture to Chinese aquaculture specialists.
Review aquaculture techniques in China for potential implementation in the USA.

Population pressures in China have produced an intense need for animal protein, an increasing amount of which can be met with aquaculture products. Economic changes have favored the development of additional taxa to the four carp species traditionally cultured together (common, silver, bighead, and grass carp). As a result, researchers in China have sought new species to culture and are seeking to test their suitability for their weather and water quality conditions. While the focus of the trip will be on yellow perch, our primary goal will be to demonstrate methods used here for amplification of native species for aquaculture, without introducing additional nonindigenous species into Asia.

The principal investigators will travel to Wuhan, Hubei Province, People's Republic of China, in October 1998 and visit the Hubei Province Fisheries Research Institute, the East Lake Fish Farm, the Chinese sturgeon institute, the Hubei State Agriculture College, the Freshwater Dolphin Research Institute, and the New World Aquarium. At each of these locations we will be making presentations on percid aquaculture, and discussing aquaculture techniques. At the Agricultural College, we will be addressing students. We will be taking written materials on these topics for distribution, and will show a video tape of European methods for culturing Perca fluviatilis, a congener of the yellow perch. We will also study methods used for aquaculture in China with the thought of implementation of some of these in American research programs.

Two trips have been made to Wuhan, People's Republic of China by the principal investigators, in October 1998 and in February 1999. Each trip was sponsored primarily by the Chinese government, with Sea Grant providing travel within the USA and a small amount of funds for specialized supplies purchased in the US for use in China.

During the first trip, the PIs concentrated on learning about the aquaculture objectives of the fish and turtle farmers in Hubei Province.

In addition, we were invited to make presentations on environmental science and aquaculture to 150 students at the Hubei Agricultural College, Jingzhou, Hubei Province. We were both awarded visiting professorships at the College.

While in Wuhan, we learned that for the traditional aquaculture techniques for carp species, the greatest cash outlay is for the inorganic fertilizers used to enrich the ponds. Because it appeared that the level of fertilizer was much higher than was required, we suggested that a change could benefit the economics of fish production for the whole country.

Between the two trips, we planned an aquaculture experiment to compare traditional Chinese fertilization techniques with those used for juvenile percids developed by Dr. Culver here in Ohio. In the former, a standard fertilization amount is added to every pond regularly, irrespective of nutrient concentrations. In the Culver method, each pond is analyzed weekly for ammonia, nitrate, and phosphate concentration, and fertilized sufficiently to raise the inorganic N and P concentrations to 1200 micrograms and 30 micrograms/liter, respectively.

In February, we purchased $3,000 worth of analytical equipment and supplies and shipped them to Wuhan. Ohio State University was then reimbursed for these expenses when we returned. We then traveled to Wuhan and spent a week teaching two scientists the chemical analytical techniques and methods of calculating the appropriate amount of fertilizer to add.

After we returned, an experiment to compare the traditional Chinese fertilization method with the Culver method was performed in four ponds, each with 2 replicates of the two methods. A combination of variegated carp and silver carp were cultured in the ponds.

Preliminary results suggest that the traditional fertilizer methods resulted in as much as 10-20 times as much ammonia and phosphate and as much as 1000 times as much nitrate as is required for producing algal blooms. The systems are thus usually light-limited rather than nutrient limited. Toxic algae, such as Microcystis, were very abundant in many of the ponds. A second set of experiments with another type of carp is now under way. We anticipate analyzing the results from all these experiments to prepare joint publications on the relative effectiveness of the two fertilization techniques.