A population study of Naineris laevigata (Polychaeta, Orbiniidae) in a fluctuating environment (Mediterranean Sea)
Adriana Giangrande, Simonetta Fraschetti

A population of Naineris laevigata Grube from lake Acquatina (Frigole, Lecce, Mediterranean Sea) was followed for 3 years, from 1989 to 1991, to describe the population dynamics and to evaluate secondary production. N. laevigata is a long lived polytelic species reproducing once a year in late spring. Recruitment was underestimated due both to the mesh size used for sampling and to the settlement of the polychaete into filamentous algae covering the sediment, which was never quantitatively examined. The analysis of population structure revealed similar trends in 1989 and 1990, when the population was dominated by adult forms, while the year 1991 was characterized by a general decrease in individual size. This was shown also by the analysis of the secondary production which ranged from 3.3 to 1.8 g AFDW/m2/yr. This was probably due to changes in the relative abundance of different year classes which in turn could be attributed to some physical and biotic modifications occurring during the period of study. In this period, some changes in the relative dominance within the polychaete assemblage occurred and competition between Naineris laevigata and the ecologically similar species Notomastus latericeus can be hypothesised.

Keywords: Polychaeta, life-history, production, brackish-water, Mediterranean Sea.
Contents of this volume Sci. Mar. 59(1) : 39-48 Back PDF
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