Reproduction activity of Exogone naidina (Polychaeta : Exogoninae) in a population from the Apulian coast (Adriatic Sea)

This study reports on the reproduction activity of Exogone naidina Orsted, 1845, followed on a hard-bottom population located at a site along the coast of Bari (South Adriatic Sea), during a year of study from November 2000 to October 2001. Population structure was analysed together with the reproductive state of individuals over time. The interpretation of frequency histograms computed on the total worm length was not easy because of the almost complete lack of juvenile forms. Ripe individuals were present for most of the year, covering a large range of sizes. The reproductive season extended from April to December, with two peaks of activity: one from April to June and one in September-October. Life span was hypothesized to be up to 1 year, with generational change clearly visible only in late summer. However, the prolonged reproductive period produces an overlapping of generations. The link between population density and the reproductive cycle of the species with food availability is also discussed