We evaluated the presence of the protozoan Perkinsus sp. by determining of its prevalence and level of infection in Atrina maura during 2012. Pen shells were collected per season beside an oyster farm located at Estero La Piedra, Sinaloa, Mexico, and analyzed by Ray's fluid thioglycollate medium and polymerase chain reaction. The higher prevalence (90%) and infection level (2.3) were obtained when temperature and salinity were higher. The Mackin scale showed a non-infected to moderate infection range. PCR was positive to Perkinsus sp. This is the first record of the presence of Perkinsus sp. in A. maura in Sinaloa, Mexico.

We studied the relation between the presence of Perkinsus sp. with growth performance (shell height-SH, body weight-BW), condition index, and biochemical composition (triglycerids, proteins, lipids, and carbohydrates) of the oyster Crassostrea gigas cultivated in two farms from Sinaloa, Mexico. Perkinsus sp. was Revista Bio Ciencias 6, e681. Perkinsus sp. in cultivated oyster./Perkinsus sp. en ostras cultivadas.