Update on the prevalence of the hookworm, Uncinaria lucasi, in northern fur seals (Callorhinus ursinus) on St. Paul Island, Alaska, 2011.

Prevalence of hookworms (Uncinaria lucasi Stiles, 1901) was determined in the northern fur seal (Callorhinus ursinus Linnaeus, 1758) on St. Paul Island (SPI), Alaska in July and August, 2011. Three of 61 (4.9%) dead pups harbored 1 to 13 adult hookworms each in their intestines. Parasitic larvae (L(3)) of hookworms were recovered from the blubber of 4 of 133 (3%) of subadult males (SAMs) examined. One parasitic L(3) was detected from each infected SAM. Adult U. lucasi (n = 3) were found in the intestine of 1 of 105 SAMs examined (0.95%). This is the first documented finding of adult U. lucasi in SAMs of the northern fur seals. Continued low prevalence of hookworms the last several years parallels the tremendous decline in the number of fur seals on SPI over a similar time period.