Page 16 - Collective Article_2017

5.4. Additional records of Siganus luridus from Lesvos, the northern limit of its range in the Aegean Sea

K. Tsirintanis & S. Katsanevakis

is quite abundant in the southern Aegean Sea (Giakoumi,
2014) but, as it is a thermophilic species, the lower tem-
peratures of the northern Aegean limit its northwards dis-
tribution. The northernmost records of the species in the
Aegean Sea are from Sigri Bay in western Lesvos Island
(Evagelopoulos et al., 2015).
Herein, we report additional records of three S. lu-
ridus individuals from southeastern Lesvos (Figs. 19 &
20), where the species had not been reported before. The
individuals were recorded during SCUBA diving sur-
veys on three different occasions (12/9/2016, 5/10/2016,
6/10/2016). The first two observations were made in the
small bay of Agios Ermogenis (39.012694° N, 26.542933°
E and 39.013258° N, 26.543022° E), and consisted of
isolated individuals grazing on brown algal assemblages
over rocky reefs. The two individuals had an estimated
length of 7-9 cm and were encountered at 1.5 and 2.5 m
depth; water temperature during the two observations
was 24° C and 22° C, respectively. The distance between
the locations of the two observations was approximately
Fig. 19: Siganus luridus individual grazing on brown algal 60 m, and the time gap was 3 weeks. The third observa-
turf, photographed at southeastern Lesvos. tion was made south of Charamida beach (39.014653° N,
26.557419° E), again over rocky reefs. An individual of
The dusky spinefoot Siganus luridus, a herbivore 14-15 cm in length was observed at a depth of 4 m, when
Lessepsian fish, has become dominant in many coastal ambient seawater temperature was 22° C.
areas of the eastern Mediterranean Sea, and has a high Due to the high impact of this species, its potential
impact on biodiversity and ecosystem services (Katsane- range expansion northwards and westwards in the Medi-
vakis et al., 2014). This is due to overgrazing that leads terranean due to its warming is of high interest. The cur-
to the transformation of the ecosystem from one domi- rent records in addition to those by Evagelopoulos et al.
nated by lush and diverse brown algal forests to another (2015) indicate the probable establishment of the species
dominated by bare rock (Sala et al., 2011). The species in Lesvos Island.

Fig. 20: Locations of previous records (black points) of Siganus luridus on western Lesvos (Evagelopoulos et al., 2015) and new
records (orange points) on the southeastern part of the island.

194 Medit. Mar. Sci., 18/1, 2017, 179-201