Population demographics and genetic diversity in remnant and translocated populations of sea otters

The effects of small population size on genetic diversity and subsequent po pulation recovery are theoretically predicted, but few empirical data are a vailable to describe those relations. We use data from four remnant and thr ee translocated sea otter (Enhydra lutris) populations to examine relations among magnitude and duration of minimum population size, population growth rates, and genetic variation. Mitochondrial (mt)DNA haplotype diversity wa s correlated with the number of years at minimum population size (r(s) = -0 .741, p = 0.038) and minimum population size, (r(s) = 0.709, p = 0.054). We found no relation between population growth and haplotype diversity, altho ugh growth was significantly greater in translocated than in remnant popula tions. Haplotype diversity in populations established from two sources was higher than in a population established from a single source and was higher than in the respective source populations. Haplotype frequencies in transl ocated populations of foundling sizes of 4 and 28 differed from expected, i ndicating genetic drift and differential reproduction between source popula tions, whereas haplotype frequencies in a translocated population with a fo unding size of 150 did not. Relations between population demographics and g enetic characteristics suggest that genetic sampling of source and transloc ated populations can provide valuable inferences about translocations.