The parasite fauna of the stone loach (Barbatula barbatula) was investigated monthly from May to December 2001. Four parasite species were recorded: Gyrodactylus spp. (Monogenea), Tylodelphys clavata (Digenea), Proteocephalus sagittus (Cestoda), and Raphidascaris acus (Nematoda). The changes in the seasonal dynamics of parasite infection were investigated throughout the 8 months. The potential effect of the reproductive investment of the host, measured by gonad mass and gonado-somatic index (GSI), on the parasite infection was tested against the prediction that, during periods of high reproductive investment (beginning of the breeding period or forming gonads after breeding), the fish are more susceptible to parasite infection. Differences between parasite loads between genders were also hypothesized. Seasonal differences in infection were observed for all parasite species studied. The values of GSI showed a pattern of energy accumulation in the pre-reproductive period and at the beginning of breeding, a decrease during breeding, and an increase in the post-breeding period. A similar pattern was observed for parasite abundance, a strong or weak increase in spring and/or autumn and a decrease during summer (July and August). Positive correlations between the abundance of Gyrodactylus spp. and R. acus and both gonad mass and GSI were found in females after eliminating the effect of fish weight. Our results suggest that stone loach females are more susceptible to parasite infection in periods of higher reproductive investment. The main factor determining the infection of T. clavata was fish size. The abundance of P. sagittus was positively correlated with GSI in the total fish sample with no detectable effect of sex or fish weight. The increase in cestode infection in spring supports the hypothesis that the parasite life cycle could by synchronized with the beginning of host reproduction, probably induced by increasing fish hormone levels in the spring.

Department of Zoology and Ecology Faculty of Science Masaryk University Kotlárská 2 61137 Brno Czech Republic

Zobrazit více v PubMed

Int J Parasitol. 1994 Apr;24(2):197-206 PubMed

Oecologia. 2001 Feb;126(3):339-344 PubMed

J Parasitol. 1998 Feb;84(1):24-8 PubMed

Parasitol Res. 2003 Sep;91(2):130-6 PubMed

Math Biosci. 1996 Oct 15;137(2):79-99 PubMed

Trends Ecol Evol. 1996 Aug;11(8):317-21 PubMed

Parasitol Today. 1992 Oct;8(10):339-42 PubMed

J Parasitol. 1997 Aug;83(4):575-83 PubMed

J Helminthol. 1999 Mar;73(1):1-19 PubMed

Does the parasite-mediated selection drive the MHC class IIB diversity in wild populations of European chub (Squalius cephalus)?

Parasitism, life history traits and immune defence in cyprinid fish from Central Europe

Seasonal changes of immunocompetence and parasitism in chub (Leuciscus cephalus), a freshwater cyprinid fish