Levels of blood haptoglobin (Hp) and interleukin-6 immunoreactive protein (IL-6 ir) were significantly elevated in river otters (Lutra canadensis) inhabiting oiled areas of Prince William Sound, Alaska (USA) following the Exxon Valdez oil spill in 1989. By May and June 1992, however, such differences were not apparent. Mean body mass of otters, adjusted for sex, age-class, and total length with analysis of covariance, differed between oiled and non-oiled areas from 1990 to 1992, but were nearly identical by May and June 1992. We propose that river otters may be recovering from chronic effects that we observed in 1990 and 1991 following the 1989 Exxon Valdez oil spill, but further research is necessary to test this hypothesis.
Noninvasive methods were validated for monitoring fecal metabolites of reproductive hormones (total estrogens and progestagens) in sea otters. Several captive female sea otters were sampled an average of two to three times per week over at least 1 year to document the reproductive hormone levels within each major reproductive event (estrus, anestrus, luteal phase, and pregnancy). We report significant differences in reproductive hormone levels consistent with most reproductive categories, as well as the minimal number of consecutive samples needed to accurately determine pregnancy using these methods.