The effect of harmful algae on the summer mortality of juvenile pacific oysters (Crassostrea gigas) ...

• Main Author: Cassis, David
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Crassostrea gigas
• Online Access: https://dx.doi.org/10.14288/1.0052590; https://doi.library.ubc.ca/10.14288/1.0052590

During the summer of 2001, a mass mortality of early juvenile Pacific oysters, Crassostrea gigas Gmelin, was observed at a farm site in Jervis Inlet, British Columbia. During this episode, several toxin producing and potentially harmful algae were detected within the phytoplankton community, with a bloom of Protoceratium reticulatum (Claparede et Lachmann) Buetschli preceding and including the mortalities. Searching for a cause we examined experimentally the rapid response behaviour of juvenile oysters to various species of microalgae. The behavioural response was a strong rejection, complete closure and feeding cessation when exposed to cultures of P. reticulatum and Alexandrium tamarense (Lebour) Balech. While exclusion in pseudo-feces (Amphidinium carterae Hulburt) and mixed reactions were observed with other species (Heterosigma akashiwo (Hada) Hada ex Sournia, Karenia mikimotoi (Miyake et Kominami ex Oda) Hansen and Moestrup, Pseudo-nitzschia pseudodelicatissima (Hasle) Hasle, and Gonyaulax spinifera ...