水產養殖 / Aquaculture (health care & water management)

Shrimp nursery could be more cost-effective in autotrophic systems

Shrimp nursery could be more cost-effective in autotrophic systems

 

Background: Seven-week trial, stocking density 900PLs/ 120L water

  • Autotrpphic system: Provided with wheat bran and plastic mesh for the formation of bioflocs and biofilms. Agricultural fertilizer was supplied to maintain a nitrogen:phosphorus (N:P) ratio around 8:1. The tanks were put outdoors and exposed continuously to sunlight. From day 5 until the end of the trial, shrimp received a formulated feed at a rate of 8 percent of their total biomass.
  • Heterotrophic system: The water column was additionally fertilized with molasses, maintained N:P ratio over 20:1. The tanks were covered with plastic shades to minimize the penetration of sunlight. From day 5 until the end of the trial, shrimp received a formulated feed at a rate of 8 percent of their total biomass.
  • Control group: used formulated feed in whole process.

Comparison 

  • The best final weights: the control(1819 mg) and the heterotrophic system(1214 mg).
  • The best survival: the autotrophic system(84.6%).
*To the outdoor nursery in Taiwan, it’s feasible for the operators to implement the autotrophic system. It would be a cost-effective way to increase the production.