Why Do Shrimps In Mexico

In the Baja California coast of Mexico, shrimp ponds were reported to be affected by algal blooms and the responsible algae were the prasinophyte Nephroselmis sp., Cochlodinium polykrikoides, Prorocentrum rhathymum, P. minimum, and Heterocapsa triquetra (dinoflagellates) and Nitzschia sigma (diatom) (Gárate-Lizárraga et al., 1999; 2004; 2006; Sierra-Beltrán et al., 2005; Gárate- Lizárraga and Muñetón-Gómez, 2008). Severe losses in shrimp farming in Mexico caused by toxic dinoflagellates and cyanobacteria have been reported by Ochoa et al. (2004) as well.
Lightner (1982) has reported that enteritis occurs in juvenile shrimps upon exposure to Schizothrix calcicola. A strain of S. calcicola has noxious effect on L. vannamei post larvae (PL). PL exposed to this cyanobacterium suffered severe gastrointestinal damage resulting in weight loss and consequent growth retardation. The authors have concluded that S. calcicola could retard shrimp growth and reduce yield (Pérez-Linares et al., 2003). Blooms caused by Cyanophyceae and Chlorophyceae form scums on the body surface of Macrobrachium rosenbergii which could lead to lethargy thus decreasing the yield (Smith et al., …show more content…
Also anoxia could alter the biological communities both inside and outside the shrimp ponds. The cyanoHAB caused by Anabaena aequalis in estuarine waters produces off-flavour and odour in cultured catfish (Ploeg and Dennis, 1992). Gymnodinium spirale blooms caused mortality of molluscs in France (Sournia et al., 1991). Schizothrix calcicola (cyanoHABs) blooms cause hemolytic enteritis which results in growth reduction in shrimps (Cortés-Altamirano and Licea-Durán, 1999). Blooms caused by Prorocentrum minimum affects the growth of shrimps and increase their vulnerability to viral diseases like hypodermic and hematopoietic necrosis (Cortés-Altamirano and Agraz- Hernández,