Juveniles of the mussel Mytilus chilensis were exposed to a diet
containing paralytic shellfish poisoning (PSP) toxins produced by the dinoflagellate
Alexandrium catenella (strain ACC02). The feeding behaviour and the
dynamics of intoxication and detoxification were evaluated over an intoxication period of
nine days, followed by a detoxification period of eight days. A significant reduction in
the feeding activity was measured during the first days of exposure to the PSP toxins
(days 0 and 2), followed by a period of recovery observed on days 5 and 9, when the
clearance rate of the contaminated mussels significantly increased. During the
detoxification period, the contaminated bivalves showed a total recovery of clearance
rate, and no significant differences were observed between contaminated and control
groups. The intoxication dynamic was characterised by a rapid and sustained increase in
the amount of PSP toxins accumulated in the tissues of the bivalves. Due to this increase,
the level of PSP toxins critical for human consumption was reached on the first day, and
at the end of the intoxication period, the mussels had accumulated 1601
μg STX eq. 100 g-1 tissue. During the detoxification period, a
decrease of PSP toxins was observed, down to 319 μg STX eq. 100
g-1 tissue. The lower clearance rates observed over the first days of
exposure would produce a decrease in the energy intake and could affect the rate of growth
of juveniles. Despite this initial effect, the rapid intoxication capacity of M.
chilensis corroborates that this species is a good indicator for the early
detection of harmful algal blooms.