MAP Technical Reports Series No. 106 UNEP

- 113 -
al., 1990) and in Southern Tyrrhenian coast (Carrada et al., 1988; 1991). The dinoflagellates are
propelled by two flagellae; some are bioluminescent. In addition to the motile form, such as A.
tamarensis, they produce resting cysts (hypnozygotes), as a result of sexual reproduction. Thus
there are two sources for contamination of shellfish with PSP: (a) motile cells of Alexandrium
species; (b) resting cysts of A. tamarensis in the sediment-water interface; the latter example
is thus not associated with a bloom phenomena.
Recent evidence indicates that bacteria present in A. tamarensis may be a source of
saxitoxin (see 7.4.4).
In the Mediterranean sea. Species of the genus Alexandrium and strains of
Gymnodinium catenatum producing PSP (Delgado et al., 1990; Bravo et al., 1990) or potentially
toxic are present in the Mediterranean sea.
The monitoring of blooms of dinoflagellates in the Adriatic sea, occurring from 1970 on
the ex-Yugoslav coasts, and from 1975 on the coasts of Emilia-Romagna, have focused on the
existence of a potential danger for this area not only because the blooms are supported by
species in the genera Gonyaulax and Gymnodinium, a group with many toxic species, but also
because in August 1982 a new species appeared, similar to Gonyaulax tamarensis (Boni et al.,
1983), a variety found in the Atlantic Ocean and in other seas, but never before found in the
Mediterranean sea. This dinoflagellate was afterwards identified as Protogonyaulax tamarensis
sensu Fukuyo (Boni et al., 1986) because of the presence of a ventral pore near the middle of
the upper right margin of the first apical plate (now called Alexandrium tamarensis (Lebour)
Balech) and linked in different zone of the world to PSP. This fact poses not only an ecological
problem, but a health problem as well.
In 1985 in the same environment a new red tide was noticed caused by a species with
resemblance to an Alexandrium fundyense Balech, since it lacked the ventral pore (Boni, 1992).
After these data other Alexandrium spp. potentially toxic were found, but not in red tides, in the
Adriatic sea and in the Gulf of Trieste: A. cf. fundyensis, A. pseudogonyaulax, A. eusitanicus
(Honsell et al., 1992), A. minutum (Honsell, 1993). In May 1994 the presence of Alexandrium
minutum (73.000 cell/l) in Northern Adriatic along the coast of Emilia Romagna was associated
with simultaneous occurrence of PSP toxins (190 µg/100g of edible tissue) in mussels (Viviani
and Poletti, 1994)
Before the discovery of Alexandrium spp. in the Adriatic sea, A. tamarensis had been
found in the Northern Tyrrhenian but not in the red tide (Innamorati et al., 1989a-b). Also in the
Gulf of Naples and Salerno A. tamarensis, A. minutum and A. balechi are present (Montresor
et al., 1990). Only in the Gulf of Salerno A. balechi caused red tide. PSP toxicity of Alexandrium
spp. in the Tyrrhenian sea is not known.
The first report of a bloom of Gymnodinium catenatum for the Mediterranean sea and
for a coastal lagoon was observed in early September 1987 at Fusaro lagoon, located on the
Southern Tyrrhenian coast (Carrada et al., 1988). Previous observations in the same lagoon
(1985, unpublished data) indicate the presence of this species from June through September.
Despite the lack of information regarding the PSP toxicity of its population, the presence of G.
catenatum in the Fusaro lagoon may represent a possible complication for the reclamation
programme aimed at restoring in the lagoon ecological conditions compatible with its centurylong
tradition (Roman times) in shellfish farming (Carrada et al., 1988). In the Mediterranean sea
the first toxic bloom (PSP) of G. catenatum has been reported along the coast of Spain (Bravo
et al., 1990) (see 7.2.1.4).