The nothward movement of termophilic fish species in the Adriatic Sea
S. Matić-Skoko and J. Dulčić
Institute of oceanography and fisheries, Spli, Croatia
Meštrovićevo šetalište 63, P.O.box. 500
21 000 Split, Croatia
correspondent author: sanja@izor.hr
The hypotesis of an expansive northward movement of termophilic species and
changes in marine biodiversity is nowdays supported with numerous records of fish
species previously characteristic to the more southern areas. Obviously, this is also
happening in the Adriatic Sea as well where intensive changes in the quantitative and
qualitative composition of the Adriatic ichthyofauna have been noted. The variations
in Adriatic temperature conditions correlate well with the North Atlantic Index
(NAO) variations showing that local temparature changes at least partly result from
hemispheric one pointing those recent changes of Adriatic biodiversity are partly
contriolled by hemispheric climate changes. Moreover, the climate changes provoke
oceanographic changes due to greater intensity of water exchange between the
Adriatic and the eastern Mediterranean, in term of greater input of wormer and more
haline mediterranean water into the Adriatic. In last three decades more than 30,
mostly thermophilic, fish species are recognized as new for Adriatic Sea. Also,
several thermophilic species, previously scarce or rare, have become more abundant
in last 10 years (1996-2006). Moreover, for 5 of them, Ruvettus pretiosus,
Plectorhinchus mediterraneus, Sphoeroides pachygaster, Campogramma glaycos,
Thalassoma pavo and Pomatomus saltatrix, which were at the beginning found only
in southern Adriatic, we are now in position to observe that they passing very well
throw adaptation process by establishing large populations at the nothernomost part of
Adriatic Sea. Also, some examples of the disappearance or increasing scarcity of
some fish species are noticed (Engraulis encrasicolus, Scomber scombrus). These
changes will provoke biological and ecological responses threw impacts on food webs
and ecosystems. The nature of these responses, acclimatization and adaptation with
changing environmental circumstances will be also discussed.
Ruvettus pretiosus
A specimen of oilfish, Ruvettus pretiosus, was captured from the northern Adriatic
(Gulf of Trieste) and represents the northernmost extension in range of this species in
the Adriatic Sea.
Plectorhinchus mediterraneus
The haemulid, Plectorhinchus mediterraneus, prevopusly unrecorded in the Adriatic
Sea, has been found recently in the Gulf of Trieste, in Diga Rizzo, Italy and, near
Piran, Slovenia.
Sphoeroides pachygaster
A juvenile specimen of pufferfish, Sphoeroides pachygaster, was captured off Cape
Kamenjak (peninsula Istra, northern Adriatic) and represents the northernmost report
in the Adriatic Sea and whole Mediterranean area.
Campogramma glaycos
One juvenile specimen of the vadigo, Campogramma glaycos, was caught on 5
December 2000 in Piran Bay (northern Adriatic). This represents a northernmost
extension in the known range of this species in the Adriatic Sea (and Mediterranean),
and first record of a juvenile specimen in the Adriatic Sea.
Thalassoma pavo
The specimens of Thalassoma pavo, were for a long time concentrated only in
southern Adriatic, but for the last 5 years this species become usual in whole Adriatic,
although, its increasing density from north to south is visible.
Pomatomus saltatrix
The unusual and surprising catch of Pomatomus saltatrix (1520.8 kg) in the northern
Adriatic (Tarska Cove, Mirna Estuary), In December, 2003 can be verified as the
northernmost record of this species in the Mediterranean area (excluding Black Sea).