The effect of parasitic castration by a ciliate on a population of Asterias vulgaris

Michel R. Claereboudt, Catherine Bouland

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Male Asterias vulgaris in Port Daniel Bay, Baie des Chaleurs, Québec Canada, were found to be infected with the ciliate Orchitophrya stellarum (Cépède). No females were infected. The parasite causes an 85% decrease in the size of the gonad in infected males, and probably accounts for the low ratio of males to females (0.52) and differences in the size distributions of males and females compared to those in an uninfected population. The castration of the males almost certainly reduces fertilization success.

Original languageEnglish
Pages (from-to)172-177
Number of pages6
JournalJournal of Invertebrate Pathology
Issue number2
Publication statusPublished - 1994



  • Asterias vulgaris
  • Asteroidea
  • Castration
  • Ciliate
  • Gonadal index
  • Orchitophrya stellarum
  • Population structure
  • Protozoan epizootic
  • Sex ratio

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Insect Science

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