Revista Chilena de Historia Natural 81 (1): 41-49, 2008
RESEARCH ARTICLE
Short-term feeding response of the mussel Mytilus chilensis exposed to diets
containing the toxic dinoflagellate Alexandrium catenella
The short-term feeding response of the bivalve Mytilus chilensis was
measured using four diets containing different proportions of the toxic dinoflagellate Alexandrium catenella. The diets
containing the highest concentrations of the dinoflagellate showed the greatest effect on the feeding activity in the mussel, with
clearance and ingestion rates significantly reduced during the first hours of exposure. After this period, M. chilensis
demonstrated a capacity to acclimate to the toxic diets, with feeding parameters reaching values similar to those of untreated
control organisms. It was not clear if the negative effect on the feeding behavior was caused by the presence of the paralytic toxin, or
due to the larger size of the dinoflagellate cells in comparison with cells of Isochrysis galbana used in the control diet.
However, parallel studies with diets containing the nontoxic dinoflagellate Alexandrium affine of similar size and shape to
that of A. catenella, suggested the cell size was the main cause for impairment of feeding behavior. The capacity for
acclimation to either toxin or cell size by M. chilensis makes it a good indicator species for the early detection of harmful
PSP events, since its relative insensitivity to the toxin allows it to quickly recover normal feeding behavior and permits it to accumulate
PSP in its tissues in a short time.
Key words:
Mytilus
chilensis, feeding response, PSP, dinoflagellates
