Effect of Schizothrix calcicola on white shrimp Litopenaeus vannamei (Penaeus vannamei) postlarvae

The noxious effect of Schizothrix calcicola strain UTEX B-1936 to white shrimp Litopenaeus vannamei (Penaeus vannamei) postlarvae is reported. The larvae exposed to this cyanobacterium during a 15-day long experiment grew smaller and weighed less (R-2 = 0.6704) than unexposed organisms (R-2 = 0.9049). Histological analysis of exposed shrimps revealed severe damage to the gastrointestinal linen. We believe that such kind of lesions may interfere with food absorption, which could explain the slow larvae growth and size development observed. Hence, S. calcicola blooms in shrimp ponds may jeopardize the culture by slowing shrimp growth rate and biomass yield. (C) 2003 Elsevier Science B.V. All rights reserved.