Health Status of Galapagos Sea Lions (Zalophus wollebaeki) on San Cristobal Island Rookeries Determined by Hematology, Biochemistry, Blood Gases, and Physical Examination

The Galapagos sea lion, Zalophus wollebaeki, is an endemic and endangered species subject to population decline associated with environmental variability, such as El Nino events, constant feeding stress, and exposure to diseases through contact with introduced species. Reference blood parameter intervals have been published for some pinniped species, but baseline biochemical and blood gas values are lacking from Z. wollebaeki. We analyzed blood samples from 30 juvenile Galapagos sea lions (19 females, 11 males) captured in two rookeries on San Cristobal Island. A portable blood analyzer (iSTAT) was used to obtain near-immediate field results for pH, partial pressure of O-2, partial pressure of CO2, bicarbonate (HCO3-), hematocrit (Hct), hemoglobin, Na, K, ionized Ca, and glucose, and blood lactate was measured using a portable Lactate Plus (TM) analyzer. Average heart rate, biochemistry, and hematology parameters were comparable with healthy individuals of other pinniped species. Hemoglobin was significantly correlated with body condition of juvenile Galapagos sea lions. When compared with available blood values of clinically healthy California sea lions, Galapagos sea lions had higher total protein and Hct and lower Ca and K levels. Our results provide baseline data that may be useful in comparisons among populations and in detecting changes in health status among Galapagos sea lions.