Soft-bottom polychaetes in a chronic eutrophic bay on the coast of Alexandria

Abstract

Context The polychaetes are the major benthos in the soft bottom of the eutrophic Eastern Harbour of Alexandria, Egypt. Aim Investigate the quantitative and qualitative dynamics of polychaete community in the Harbour. Methods Polychaetes were collected bimonthly from August 2018 to June 2019, by using a 29- × 16-cm grab. Key results In total, 54 polychaete species were identified, belonging to 27 families and 51 genera. The family Syllidae was represented by eight species, Spionidae by five species, and Cirratulidae by five species, against one to three species from all other families. Eleven alien species were recorded, including four new to the Mediterranean Sea (Caulleriella cristata, Armandia casuarina, Spio blakei and Prionospio lighti). The polychaete community displayed pronounced temporal variations in both species diversity and numerical abundance at the two sampled sites. Conclusion This study showed high diversity and abundance of polychaetes in such eutrophic basin. Implications The eutrophication may play a role in the structure and count of polychaetes in the Eastern Harbour.