Increased Contracaecum osculatum infection in Baltic cod (Gadus morhua) livers (1982-2012) associated with increasing grey seal (Halichoerus gryphus) populations.

TY - JOUR

T1 - Increased Contracaecum osculatum infection in Baltic cod (Gadus morhua) livers (1982-2012) associated with increasing grey seal (Halichoerus gryphus) populations.

AU - Haarder, Simon

AU - Kania, Per Walter

AU - Galatius, Anders

AU - Buchmann, Kurt

PY - 2014/7

Y1 - 2014/7

N2 - Grey seals (Halichoerus gryphus), the main final host of the gastric parasitic nematode Contracaecum osculatum in the Baltic, have recently recolonized the southwestern Baltic Sea. This colonization could lead to an increase in prevalence and intensity of third-stage larvae of C. osculatum in livers of Baltic cod (Gadus morhua), which serve as transport host for this helminth.We performed a parasitologic study of cod in spring 2012 and compared the results with previously unpublished data from 1982/1983. Additionally, grey seals were counted annually from 2000 to 2011 at three haul-out sites in the southwestern Baltic. Of 97 cod livers examined in the 1982/1983 survey, 22%harbored C. osculatumlarvae, whereas 55.1%of the examined cod livers (n=185) were infected in 2012; themean intensity and mean abundance increased from 4.3 and 0.9 to 20.2 and 11.1, respectively. Molecular identification (PCR) confirmed the identity of the larvae. The grey seal population increased markedly during the 12-yr period. We suggest that the elevated parasitism of cod livers is associated with the successful re-establishment of grey seals in the southwestern Baltic.

AB - Grey seals (Halichoerus gryphus), the main final host of the gastric parasitic nematode Contracaecum osculatum in the Baltic, have recently recolonized the southwestern Baltic Sea. This colonization could lead to an increase in prevalence and intensity of third-stage larvae of C. osculatum in livers of Baltic cod (Gadus morhua), which serve as transport host for this helminth.We performed a parasitologic study of cod in spring 2012 and compared the results with previously unpublished data from 1982/1983. Additionally, grey seals were counted annually from 2000 to 2011 at three haul-out sites in the southwestern Baltic. Of 97 cod livers examined in the 1982/1983 survey, 22%harbored C. osculatumlarvae, whereas 55.1%of the examined cod livers (n=185) were infected in 2012; themean intensity and mean abundance increased from 4.3 and 0.9 to 20.2 and 11.1, respectively. Molecular identification (PCR) confirmed the identity of the larvae. The grey seal population increased markedly during the 12-yr period. We suggest that the elevated parasitism of cod livers is associated with the successful re-establishment of grey seals in the southwestern Baltic.

U2 - 10.7589/2012-12-320

DO - 10.7589/2012-12-320

M3 - Journal article

C2 - 24779467

SN - 0090-3558

VL - 50

SP - 537

EP - 543

JO - Journal of Wildlife Diseases

JF - Journal of Wildlife Diseases

IS - 3

ER -