Abstract
Blood values of wild cetacean population are a valuable tool to drive proper management of threatened species. Reference intervals of 26 serum analytes were determined from 107 apparently healthy Amazon river dolphins ( Inia geoffrensis ) wild‐caught in the Mamirauá Sustainable Development Reserve (3°3′S, 64°51′W), central Amazon, Brazil. No differences were detected between males and females or between pregnant and nonpregnant females. Calves had higher serum calcium than juveniles and adults, and alkaline phosphatase activity was higher in calves and juveniles than adults as a result of bone growth. Adults showed higher creatinine levels than juveniles due to higher body mass, and higher urea than calves. Positive correlation was found between body length and body weight with creatinine, urea, and alanine aminotransferase activity; whereas calcium and alkaline phosphatase and creatine kinase (CK) activities negatively correlated with these body parameters. Cardiac rate and respiratory frequency appear to have not correlated with any serum analyte, while stress level positively correlated with CK. Storage of frozen samples for 60 days at −80°C significantly altered 10 of the 19 analytes after one freeze–thaw cycle. Important differences were detected among age classes, stress level, and sample storage and should be taken into account before any clinical or physiological interpretations.