Publication Abstract

Analysis of temporal and spatial distribution of 686 egg masses and egg mass groups recorded by recreational divers and posted in the various public media, scientific survey data collected during research programs and publications in peer-reviewed literature demonstrated that the reproduction of Loligo squids occurs throughout the Lusitanian zoogeographical province all year round with varying seasonal peaks. This may be due to high phenotypic plasticity, with the life cycle adapting to local conditions, or the existence of small discrete stock units related to individual water features. In warmer and relatively productive waters the spawning peak is more extended, and percentage of mature females in catches is lower. In the Mediterranean the peak of occurrence of both mature females and spawned eggs gradually shifts to earlier dates from the west to the east, which is in line with respective changes of the earlier peak of productivity. There is little or no gap between peak of occurrence of mature females and peak of the egg mass records. Spawning grounds of L. vulgaris expand much deeper than thought before and in the Mediterranean area they extend from 3 m to 550 m. Egg masses are reported by recreational scuba divers from deeper locations in the central Mediterranean than in other areas. Loligo forbesii egg masses are found between 170 and 720 m.

Vladimir Laptikhovsky*, Ana Moreno, Daniel Oesterwind, Catalina Perales Raya, Graham J Pierce, Jean-Paul Robin, Ignacio Sobrino, Maria Valls, Roger Villanueva, Athena Allen, Esther Abad, Giambattista Bello, Bianca Tanja Carina Bobowski, Fernando Ángel Fernández-Álvarez, Miguel Cabanellas-Reboredo, Ángel F. González, Jorge Hernández-Urcera, Svjetlana Krstulović Šifner, Evgenia Lefkaditou, Eleanor MacLeod, Julio Valeiras Mota, Bahadir Onsoy, João Pereira, Alp Salman, Sonia Seixas, Anne Marie Power