Confirmation of the presence of a domoic acid (DA)-specific antibody in naturally exposed California sea lion (Zalophus californianus) serum samples as detected via an indirect enzyme-linked immunosorbent assay (ELISA).

CSL = California sea lion; W = Wild; C = control healthy animals born and raised in captivity at Sealife Park Hawaii with presumably no history of domoic acid exposure; Absorbance Ratio = sample serum absorbance÷(mean control serum absorbance+3SD); Values >1 indicate presence of DA-specific antibody; nd = not detectable; na = not applicable;aNumber of days after admission to the Marine Mammal Center before serum was collected.