Due to the impact of white spot disease of P. Monodom, farmers in Asia have already turned to P.Vannamei cultivation four years ago. The P. Vannamei won’t die largely in the same time due to the different characteristics and the production of P. Vannamei in Asia was therefore increased rapidly. Most of the country in Asia that originally cultivated P. Monodom, but now more than 80% of them has changed to cultivate P. Vannamei.

    Under the pressure of high mortality experienced in the P. Monodon, almost all the harvesting size of Vannamei in Asia are concentrated on the minimum market size, 10~15g. Under the circumstances, the market price is dropped badly due to the over supply for the shrimp of this size and that influence the profit of farmers deeply.

    As regard to the size of 20~30g Monodom, it ranked better market price but the supply is few and it become a clear and strong comparison to the P. Vannamei. Therefore, if the Vannamei farmer want to improve their profit, it is necessary to consider adopting the following methods to cultivate the Vannamei up to 20~30g and obtain better price:

1. Adopt fish and shrimp polyculture for those species of the same water quality requirement. This is to balance the bacteria condition, save operation cost and secure the Vannamei production. 85% of Taiwan’s Vannamei production is from polyculture.

2. Rotation fish and shrimp culture. This is to adjust the pond environmental condition and reduce the chance of disease infection. However, polyculture and rotation culture are usually difficult to be accepted by farmers because they feel the culture area, time and expected profit for shrimp is decreased by 50%.

3. Adopt closed system water treatment additive for high-density culture to minimize the vibrio population and the content of ammonia as well as nitrite acid in the pond so as to decrease the chance of mass mortality incurred by the shrimp complication. The pond vibrio population is an important index to identify the health condition of shrimp.

4. Using the Hawaii specific pathogen resistance (SPR) healthy P. Vannamei to increase the possibility of a more successful production. This SPR Vannamei not only show negative for TSV,WSSV,BPV,IHHNV,YHV and HPV, but also get 81~88% high survival rate under the TSV attack, conducted by the University of Arizona and Oceanic Institute.

Like other animal, the virus-resistant ability of SPR healthy Vannamei may decrease after three to four generations. From time to time, it is needed to introduce new parent prawn to keep the virus-ability standard. The harvesting size of Taiwan’s fresh water shrimp (Macrobrachium rosenbergii) becomes smaller and smaller due to the problem of inbreeding and also the market price could not cover the increasing production cost.

Use the virus-resistant and more accommodating ability species just like a new functional product to the market that brings more efficiency and new evolution. We also expect more newly improved shrimp species can be introduced to this industry so as to make the aquaculture more successful.

    Mostly the loss is because of the over persistence to the past experiences, confidences and improvement are developed from updated technology. It is always fast and safe to learn and use the method being used by those successful farms that already have good production.