Patterns of infection by monogenoideans in an assemblage of darters

Abstract

The study of host-parasite relationships is useful in understanding what might affect host fitness, especially in terms of reproductive success. This study examined infection levels of monogenoidean gill parasites on several species of percid fishes of the genus Etheostoma, especially E. simoterum (Tennessee Snubnose Darter) and also E. caeruleum (Rainbow Darter), E. flabellare (Fantail Darter), and E. kennecotti (Stripetail Darter) through a year-long survey of monthly samples of 11-61 fish from a tributary of the Paint Rock River in northeast Alabama, USA. Among E. simoterum, a range of 0-7 parasites per host was found, with almost 18% of fish examined carrying gill parasites with a mean of 1.9 parasites. Correlations were identified between host breeding season and parasite infection levels, with host breeding months (spring) having the highest infection rates. Etheostoma simoterum length, mass, gender, and condition index were found not to be predictive of monogenoidean gill parasite infection levels. This is consistent with other temperate freshwater teleosts and strongly suggests that the parasite's reproduction and dispersal are timed with the host's reproductive season when water temperature has risen and the host may be immunocompromised. Based on the examination of confocal microscopic imagery, the monogenoidean parasites collected from E. simoterum are of a single unnamed type and are tentatively identified as Aethycteron simoterum sp. novum. © 2013 Taylor and Francis Group, LLC.