Marine Mammal Parasite of the Month- January 2022


This parasite is a lungworm and earworm in the family Pseudaliidae and it is the most common parasite in the ear of harbor porpoises in the Gulf of St. Lawrence, the Bay of Fundy, the French Atlantic, and the Baltic Sea. In general, this parasite is found in high densities. A limited number of studies have investigated the presence of this parasite in harbor porpoises. Most of them include porpoises that were shot, caught as bycatch, or stranded and the parasite was found during necropsies. Based on these studies, this parasite has been found in 25% to 100% of porpoises depending on the study location. It was hypothesized this may have something to do with diet or water temperature affecting the transmission of the parasite. Male parasites are lost over time whereas mature female parasites have been found in both juvenile and adult porpoises (although the number of offspring they produce likely declines over time). Fun fact: this parasite has not been found in newborn porpoises and it’s speculated that they become infected once they start eating on their own, but it has not been reported in any intermediate hosts. What parasite do you think this is?

Posted by fall intern, Adrienne V-H.