Global warming scenarios for the Eastern Adriatic Sea indicate a higher risk of invasiveness of non-native marine organisms relative to current climate conditions

Globally,marine bioinvasions threaten marine ecosystem structure and function,with the Mediterranean Sea being one of the most affected regions.Such invasions are expected to increase due to climate change.We conducted a risk screening of marine organisms(37 fishes,38 invertebrates,and 9 plants),both extant and‘horizon’(i.e.,not present in the area but likely to enter it).Based on expert knowledge for the Eastern Adriatic Sea coasts of Slovenia,Croatia,and Montenegro,screenings were conducted under both current and predicted climate conditions indicating with an increase in sea surface temperature and salinity of the Adriatic Sea together with changes in precipitation regime.Our aims were to:(1)identify non-native extant and horizon marine species that may pose threats to native biodiversity and(2)evaluate the risk of invasiveness of the selected species under current and predicted climate conditions.Of the 84 species screened,there was an increase in those ranked as‘high risk’from 33(39.3%)under current climate conditions and to 47(56.0%)under global warming scenarios.For those ranked as‘very high’risk,the increase was from 6(7.1%)to 21(25.0%).Amongst the screened species,the already established high-risk species Pacific oyster Magallana gigas and Atlantic blue crab Callinectes sapidus represent a threat to ecosystem services.Given the under-representation of marine species in the current European Union List,the species we have ranked as high to very high risk should be included.

Embryonic and larval development of garpike from the Adriatic Sea

Although information about embryonic and larval development of garpike,Belone belone(Linnaeus,1761),is present in the published literature,the bulk of research concerns garpike from the northeastern Atlantic Ocean and the Baltic Sea.The present work describes the embryonic and larval development of garpike,Belone belone,from the Adriatic Sea,and methods used for incubation of fertilized eggs in aquarium conditions.Because garpike is,as suggested by some authors,divided into subspecies,we conclude that some differences in embryonic development could also be expected.In the present study,eggs were fertilized using the dry fertilization method and were incubated in a tank equipped with aeration and constant sea water flow.Salinity and content of dissolved oxygen were constant,and the temperature varied between 19.4 and 22.3°C.Eggs were spherical,measuring 3071.9±75.73μm in diameter.Yolk sacs were homogeneous and did not contain oil globules.The first larvae hatched 329 h and 47 min after fertilization.Absorption of the yolk sac occurred 17 h–48 h after hatching and the total length of newly hatched larvae was 9.78 mm.The peculiarities observed in the embryonic and early larval development are evidence of an exceptional plasticity and adaptive potential,which could be considered as helpful features in extending the natural range of occurrence of this species.