Shrimp Production Results in Experimental Ponds in Ecuador with Presence of WSSV: Three Lucky Strikes or Three Indications of Hope for the Shrimp Industry?

Abstract

Since the very first appearance of White Spot Syndrome Virus (WSSV) in April 1999 in
Central and South America, massive mortalities of Pacific white shrimp, Litopenaeus
vannamei (Boone), in semi-intensive ponds are occurring. In very few cases shrimp
survival is above 25 %. Three experiments were conducted in Ecuador from March 2000 to
May 2001 to compare production results of shrimp directly stocked in 100 m2 ponds at
150000 PL-12 / Ha. Experiment 1 evaluated immunostimulants, spray-dried plasma,
tolerins and antibiotics in the feed. Production results were not significantly different
among treatments that ranged from 800 to 1200 kg / Ha. Experiment 2 evaluated the use of
Ca(OH)2 and water exchange in plastic-lined and earthened ponds. Production results were
significantly higher in lined ponds and ranged from 400 to 850 kg / Ha. Experiment 3
evaluated the use of kelp meal, wheat gluten, and a synthetic binder in the feed. Production
results were not significantly different among treatments that ranged from 1100 to 1400 kg
/ Ha. It is speculated that these good production results were mainly obtained due to
complete experimental system dry-out between culture cycles and water filtration through
300 μm mesh screen to fill ponds that probably resulted in reduced WSSV load in the
culture system.