ACADEMIA Letters A sight for sore eyes: the relationship between Diplostomum von Nordmann, 1832 and Tylodelphys Diesing, 1850 in perch (Perca fuviatilis L.) in the Erne Catchment (Ireland). Thomas McCloughlin, DCU Water Institute Abstract Diplostomum and Tylodelphys inhabit the eyes of freshwater fsh throughout the world. In- cidence of Diplostomum spp. and Tylodelphys clavata in Perca fuviatilis in Ireland was recorded with the age of the fsh hosting the parasites. A generalized linear model, GLZ, was applied to the data, following the failure of other statistical methods to confrm any rela- tionship between the genera. Whereas a linear model was used within the GLZ and the results were signifcant, the use of a Gamma distribution in Diplostomum pointed to the nature of the actual distribution of Diplostomum. It was found that Diplostomum formed a relationship with the age of the fsh host, but Tylodelphys did not, as it is an annually reinfecting parasite, but that both genera exerted an infuence on each other, based on cross-wise interactions. Further work is required to determine the nature of these interactions, but it is suggested that at higher abundances of one genus there is a barrier to infection for the other. Keywords: Diplostomum, Tylodelphys, generalized linear model, metacercariae Introduction Tylodelphys Diesing, 1850 and Diplostomum von Nordmann, 1832 are trematode parasites Academia Letters, July 2021 Corresponding Author: Thomas McCloughlin, tom.mccloughlin@dcu.ie Citation: McCloughlin, T. (2021). A sight for sore eyes: the relationship between Diplostomum von Nordmann, 1832 and Tylodelphys Diesing, 1850 in perch (Perca fuviatilis L.) in the Erne Catchment (Ireland). Academia Letters, Article 2407. https://doi.org/10.20935/AL2407. 1 ©2021 by the author — Open Access — Distributed under CC BY 4.0