MAP Technical Reports Series No. 106 UNEP

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7.3.1.4 Occurrence of Prorocentrum minimum in the Mediterranean sea
Changes in the phytoplankton composition due to the occurrence and progressive
proliferation of species previously rare or unknown have been reported from the Adriatic during
recent years by Marasovic and Pucher-Petkovic (1985) and Marasovic (1986). In their view,
these changes often accompanied by a substantial increase in primary productivity, both in
inshore and offshore waters of the central Adriatic, were due primarily to increased
eutrophication resulting from urban development and riverborne wastes. A case in point noted
by Marasovic (1986) is the increasing occurrences in recent years of the potentially toxic
dinoflagellate Prorocentrum minimum. During the summer months of 1983 P. minimum
(Pavillard) Schiller, not earlier recorded from the Adriatic, constituted a considerable proportion
of the regular summer bloom in the Sibenik Bay (eastern Adriatic coast). During the subsequent
years (1984, 1985, 1986) the proportions of P. minimum in summer blooms in the Sibenik Bay
was constantly increasing (Marasovic et al., 1990). At the same time its presence was reported
from the other parts of the Adriatic coast, attributed to the intensified eutrophication of the Adriatic
waters (Mancini et al., 1986; Marasovic et Pucher-Petkovic, 1987; Pucher-Petkovic and
Marasovic, 1988; Marasovic et al., 1988; Pucher-Petkovic et al., 1988; Marasovic, 1989). Also
red tides of P. minimum occurs in coastal lagoon (etaug de Berre) in French Mediterranean
coastal area (Leveau et al., 1989). Venerupin shellfish poisoning have never been detected in
the Adriatic sea and in etang de Berre.
7.3.1.5 Methods of analysis for venerupin
Toxic principles of P. minimum inducing venerupin poisoning were tested by
intraperitoneal injection into mice of 75% methanol extracts of samples of bivalves (Okaichi and
Imatomi, 1979; Tangen, 1983). If toxins were present mice died within 24-48 hr. The relationship
between the dose and the time of death was not ascertained (Okaichi and Imatomi, 1979).
7.3.1.6 Human intoxication
The poisoning is characterized by a long incubation (24-48 hr), and sometimes longer
(Halstead, 1965; Okaichi and Imatomi, 1979; Tangen, 1983). The heat-stable toxin induces the
rapid onset of nausea, vomiting, diarrhoea, headache and nervousness. In serious cases,
jaundice may be present, and petechial haemorrhages and ecchymosis may appear over the
chest, neck, and arms. Leucocytosis, anaemia, and a prolonged blood-clotting time are
sometimes observed. The liver is usually enlarged. In fatal poisoning, acute yellow atrophy of the
liver, extreme excitation, delirium and coma occur with death reported in up to 33% of victims
(Auerbach, 1988).
7.3.1.7 Therapy
Therapy is based upon symptoms and is supportive. Any victim who shows the early
symptoms of gastroenteritis should be placed on a low-protein diet and observed for 48-72 hr
for signs of liver failure. There is not yet clinical experience with exchange transfusion,
chemotherapy, hemoperfusion, or liver transplantation in the management of profound liver
failure associated with this disorder (Auerbach, 1988).
7.3.2 Nitzschia spp. and Amnesic Shellfish Poison (ASP)
As regards eutrophication phenomena, diatoms were not considered as problematic
as dinoflagellates until the end of November 1987, when 153 cases of acute intoxication