RESEARCH ARTICLE C. Rosas Æ E. L. Cooper Æ C. Pascual Æ R. Brito R. Gelabert Æ T. Moreno Æ G. Miranda Æ A. Sa´nchez Indicators of physiological and immunological status of Litopenaeus setiferus wild populations (Crustacea, Penaeidae) Received: 10 April 2003 / Accepted: 26 January 2004 / Published online: 20 March 2004 Ó Springer-Verlag 2004 Abstract Constant environmental changes in oceanic and estuarine systems due to human activity in coastal zones require different tools and strategies for their study to be able to assess the health status of aquatic ecosystems. The Gulf of Mexico has a tremendous ecological importance because of its biological diversity. Baseline levels of blood metabolites and immune components were defined for wild tropical populations of Litopenaeus setiferus, an important shrimp species of the Gulf of Mexico. Osmotic pressure, oxy hemocyanin (OxyHc), glucose, proteins, cholesterol, lactate, and triacylglycerols (TAG) were used as indicators of physiological status; pro phenol- oxydase (proPO) and phenoloxydase (PO) quantification of hemocytes, as well as respiratory burst, were used to assess the immunological status. Significant differences were observed in live weight of juveniles, males, and females of L. setiferus with mean values of 10.54, 35.05, and 40.33 g, respectively. A value of 460 mOsm/kg was recorded in the water where juveniles were sampled and 1,000 mOsm/kg in adult sampling zones. Conse- quently, the osmotic pressure of L. setiferus juveniles (718.02 mOsm/kg) was 22% lower than in adults (925 mOsm/kg); there were no differences between sexes. A significantly lower value in juvenile OxyHc was observed. This value was 24 and 16% lower than that observed in males and females, respectively. Hemolymph glucose, cholesterol, and triacylglycerol levels were not statistically different between shrimp stages, showing median values of 0.19, 0.32, and 0.39 mg/ml of glucose, cholesterol, and triacylglycerols, respectively. Hemocya- nin was distributed normally in the juvenile–male pop- ulation but not in females. A proportion between 52 to 81% of OxyHc of the total protein (OxyHc/Prot) was obtained for all stages. Digestive gland glycogen showed no normal distribution in juveniles and adults. Digestive gland glycogen was significantly higher in juveniles (median value of 2.64 mg/g) than in adults (median value of 1.58 mg/g). A higher value of lactate (0.11 mg/ml) was observed in juveniles than in males (0.09 mg/ml) and females (0.04 mg/ml). Granular cells (GC) corresponded to 36, 44, and 39% of the total hemocytes (TH) observed in juveniles, males, and females. ProPO showed no nor- mal distribution in all stages. A high proPO activity was recorded in L. setiferus females that was 95% higher than in the juvenile–male group. Respiratory burst was di- vided into two groups, juveniles–males and females, and was distributed normally in both. Female respiratory burst values were 40 and 45% higher than those observed in the juvenile and male groups, respectively. There was an increment in OxyHc, proteins, PO, hemocytes, and respiratory burst with an increase in body weight. In contrast, the relationship of live weight to glucose, TAG, and proPO revealed no significant regressions. A signif- icant decrease in cholesterol, glycogen, and lactate with an increase in body weight was also observed. We now have indicators of nutritional and immune status of juveniles and adults that can reveal changes in trophic relations and health at the population level. This will serve as a basis for using L. setiferus as environmental Communicated by P.W. Sammarco, Chauvin C. Rosas (&) Æ C. Pascual Æ A. Sa´nchez Laboratorio de Ecologı´a y Biologı´a Marina Experimental, Fac. de Ciencias, Universidad Nacional Auto´noma de Me´xico, Calle 8 A No. 248·5, Vista Alegre Norte, 97130 Me´rida, Yucata´n, Mexico E-mail: crv@hp.fciencias.unam.mx E. L. Cooper Laboratory of Comparative Immunology, Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1763, USA R. Brito Æ R. Gelabert Facultad de Ciencias Pesqueras, Universidad Auto´noma del Carmen, Cd. del Carmen, Campeche, Mexico T. Moreno Facultad de Quı´mica, Universidad Auto´noma del Carmen, Cd. del Carmen, Campeche, Mexico G. Miranda Regio´n Marina Noreste, PEMEX-Exploracio´n y Produccio´n, Cd. del Carmen, Campeche, Mexico Marine Biology (2004) 145: 401–413 DOI 10.1007/s00227-004-1321-y