Impact of a mouth parasite in a marine fish differs between geographical areas

Abstract

Considerable variation exists in parasite virulence and host tolerance which may have a genetic and/or environmental basis. In this article, we study the effects of a striking, mouth-dwelling, blood-feeding isopod parasite (Ceratothoa italica) on the life history and physiological condition of two Mediterranean populations of the coastal fish, Lithognathus mormyrus. The growth and hepatosomatic index (HSI) of fish in a heavily human-exploited population were severely impacted by this parasite, whereas C. italica showed negligible virulence in fish close to a marine protected area. In particular, for HSI, the parasite load explained 34.4% of the variation in HSI in the exploited population, whereas there was no significant relationship (0.3%) between parasite load and HSI for fish in the marine protected area. Both host and parasite populations were not differentiated for neutral genetic variation and were likely to exchange migrants. We discuss the role of local genetic adaptation and phenotypic plasticity, and how deteriorated environmental conditions with significant fishing pressure can exacerbate the effects of parasitism. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 842–852

Annual variation of parasite communities of deep-sea macrourid fishes from the western Mediterranean Sea and their relationship with fish diet and histopathological alterations

“…In the present study, some (not significant) tendency was observed between fish condition and parasite load among seasons. The negative relationship between high parasite loads (MSR) and condition of fish (HSI) in N. aequalis agrees with findings of several authors (Durieux et al, 2007;Lloret et al, 2012;Sala-Bozano et al, 2012), however, this trend is not always clearly evident or easy to identify (Lloret et al, 2012) as in the case of H. italicus and T. scabrus. By contrast, the relationship between the GSI and parasite load (MSR and MDI) tended to be positive in N. aequalis, in agreement with Abattouy et al (2011) who attributed it to a detrimental effect in immune defence.…”

How have fisheries affected parasite communities?

“…;Lafferty et al 2008b;Freeman and MacDiarmid, 2009;Ternengo et al 2009;Marzoug et al 2012;Sonnenholzner et al 2011;Sala-Bozano et al 2012;Wootton et al 2012;Wood et al 2013).…”

A Review of Molecular Approaches for Investigating Patterns of Coevolution in Marine Host–Parasite Relationships

“…However, microsatellite analyses did not detect spatial differentiation or differentiation according to host species, which points to random mating and high gene flow between parasitic crabs from the two hosts. A further study by Sala-Bozano et al (2012) applied microsatellites to investigate neutral genetic variation in an isopod mouth parasite (Ceratothoa italica) and its fish host, Lithognathus mormyrus. Here both host and parasite populations were not genetically differentiated and thus likely exchanged migrants.…”