Figure 1

Sampling locations of Gongolaria barbata and the global Sea surface circulation (grey arrows). Each study site is labeled as follow: (A) in the Ionian Sea: 1—Porto Cesareo—Isola Scoglio (Italy), 2—Porto Cesareo (Italy), (B) in the Adriatic Sea: 3—Conero (Italy), 4—Kornati (Croatia), 5- and 6—Boka Kotorska (Montenegro), and (C) in the Black Sea: 7—Costinesti (Romania), 8—Kaliakra (Bulgaria), 9–11—Ropotamo Kiten (Bulgaria), 12—Sile (Turkey), 13—Sinop (Turkey), 14—Karadagand (Ukraine) and 15—Tarhankut (Ukraine). GPS coordinates are provided in Table 1. The map was created using the R package mapdata^105,106,107.