The brown shrimp Penaeus aztecus Ives, 1891 (Crustacea: Decapoda: Penaeidae) spreading northern in the Adriatic Sea: a first record from Croatia.
The brown shrimp Penaeus aztecus Ives, 1891, a well-established alien species in the Mediterranean Sea, is here recorded from Croatia (central-northern Adriatic Sea) on the basis of 18 specimens found since November 2016. Such numbers triple the number of confirmed specimens known from the basin so far and testify its northern spreading in the Adriatic Sea. There are no certainties regarding possible pathway(s) of arrival of this species in the area. However, unaided dispersal from neighbouring countries constitutes the most probable one, although introduction through ballast water or deliberate introduction or escape from aquaculture facilities cannot be ruled out. All the specimens were captured while trawling on muddy substrates at depths ranging from 50 to 200 m, and were communicated to the authors of the present note by local fishermen. This confirms the importance of fishermen knowledge to detect the occurrence of non-indigenous megafauna in the Adriatic Sea as a complementary tool to proper scientific surveys.