Parasites and Swimming Performance in Estuarine Fish
Eric McElroy, College of Charleston
15 Feb 2013
Parasites are organisms that usurp host resources in order to enhance their transmission and increase their fitness. This often results in a change in host physiology, performance and behavior that compromises host fitness. I will present two studies that examine the role of parasites in shaping swimming performance in estuarine fishes. First, the southern flounder Paralichthys lethostigma is host to a philometrid nematode Philometroides paralichthydis that embeds and destroys the flounder’s fin musculature. As a result, infected juvenile flounder have lower maximum swimming speed. This decrease in swimming performance may render infected juveniles more vulnerable to predation and may explain why adult flounder never harbor this philometrid nematode. Second, spotted seatrout Cynoscion nebulosus are host to myriad parasites. Two species directly impact organ systems relevant to swimming performance. The myxosporidian Kudoa inornata infects and destroys seatrout skeletal muscle, while eggs of the trematode Cardicola laruei infect seatrout heart musculature. Increased density of these parasites increases swimming performance in juvenile spotted seatrout, an unexpected result. Current efforts are focused on discovering the cellular and molecular basis of this counter-intuitive effect of a parasite on its host’s physiological performance and at examining how the parasite impacts performance as seatrout grow.