Variation in the prevalence of the externally visible pathological symptoms affecting Baltic herring
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Авторы
Grygiel,W.
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Pensoft Publishers
Аннотация
Описание
Geographical distribution of Baltic herring (Clupea harengus membras (L., 1761)) affected with externally visible pathological symptoms is demonstrated, based on the observations of 5 028 individuals. The fish were collected in period 25.11-08.12.1994, from 36 sampling hauls performed on a transect from the south-western to the north-eastern Baltic Sea. The results of analyses indicate statistically significant differences in the fraction of herring with externally visible diseases (mean percentage of 3.7%) dependent on the geographical area. A relationship between the prevalence of emaciation (mean prevalence of 3.3%), infection (mean prevalence of 3.7%) in herring with the parasitic larvae of Anisakis simplex (Rudolphi, 1809), and the area of sample collection was shown to exist.