Population dynamics of the calanoid copepod Acartia italica Steurer in a small saline lake

Abstract

      The calanoid copepod Acartia italica is the only metazoan plankton species surviving and reaching high abundance in the middle Adriatic saline coastal Lake Rogoznica. Seasonal variations in the abundance of nauplii, copepodites, adults and their faecal pellets were assessed in the period January 2000 to December 2004. Development and behaviour of A. italica were regulated by thermohaline conditions, biology (phytoplankton, bacteria, ciliates), and chemistry (organic matter, dissolved oxygen, reduced sulphur species) of the lake. The diatom Chaetoceros curvisetus could provide important food for A. italica adult specimens; however, great diatom abundances could reduce copepod reproductive ability. This study show that top-down control which characterized the lake ecosystem before the disastrous anoxia event in 1997 were re-established again.