Effect of parasite infection on overwinter mortality in juvenile fish
| Authors | |
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| Year of publication | 2012 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Body condition and parasite abundance was examined in early- and late-hatched European bitterling Rhodeus amarus during the first overwintering period in two seasons. Body condition in early-hatched fish did not change during winter, and increased significantly in March. From November to February, late-hatched fish showed a decreasing trend in condition. Despite a significant increase in March, however, late-hatched fish condition only reached the same level as before winter. Total parasite abundance increased significantly in winter in both fish size-classes, reflecting a seasonal increase in monogenean infection. Early-hatched fish were parasitized significantly more than late-hatched fish during winter, but only in late-hatched fish was a negative correlation between parasite infection and condition found and a significant decrease in parasite abundance recorded after wintering, indicating mortality of heavily infected individuals with low condition during the winter. A trend for higher overwinter mortality in late-hatched fish was found under semi-experimental conditions. The decrease in condition during the winter period in late-hatched fish corresponds with faster energy depletion generally expected in smaller individuals. Our results suggest that parasite infection may influence overwinter survival of 0+ R. amarus, with a stronger effect in smaller individuals. |
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