A hypothesis on the fate of blooms of doliolids (Tunicata, Thaliacea)

Abstract

There are repeated reports in the literature of the sudden appearance and disappearance of dolioid blooms. While there is ample information on parasites and predators of salps, such information is rare for doliolids. While other variables like food organisms of different quality and their supply cannot be excluded, parasites and predators may have a major impact on bloom persistence. From 2009 to 2012 large nurses of Dolioletta gegenbauri with only short cadophores were found during 16 cruises. This observation suggested the hypothesis that the removal by predators of longer cadophores, with their trophozooids and budding phorozooids, often prevents the development or maintenance of doliolid blooms on subtropical continental shelves. © 2013 The Author.