IngentaConnect Spatial and Temporal Abundance Distribution of Chaetognaths in Ea...

Author: George Kehayias

Source: Bulletin of Marine Science, Volume 74, Number 2, 1 March 2004 , pp. 253-270(18)

Publisher: University of Miami - Rosenstiel School of Marine and Atmospheric Science

Abstract:

The abundance distribution of chaetognaths in pelagic waters (0–300 m) of the eastern Mediterranean Sea was investigated during autumn 1991 and spring 1992. The sampling stations were situated in four areas: the Ionian, the Cretan, the Rhodes Seas, and the Cretan Passage. The abundance of chaetognaths showed a clear geographical heterogeneity in both seasons. During autumn, high densities of all chaetognaths combined were recorded in the Ionian Sea and the Cretan Passage, while during spring the highest density was found in the Cretan Sea. The lowest densities were recorded in the Rhodes Sea during both seasons. The epipelagic species Sagitta enflata (Grassi, 1881), Sagitta serratodentata (Krohn, 1853), Sagitta bipunctata Quoy and Gaimard, 1827, and Sagitta minima (Grassi, 1881) dominated the total community in the Ionian Sea and the Cretan Passage, while the mesopelagic species Sagitta lyra (Krohn, 1853), Sagitta decipiens (Fowler, 1905), Sagitta hexaptera (d'Orbigny, 1834), and Krohnitta subtilis (Grassi, 1881) were dominant in the Cretan and the Rhodes Seas. The spatial distribution of the chaetognath community may have been influenced by the presence of their food (mostly copepods) and the complex hydrography of the area. The abundance differences between the two sampling periods were negligible and were confined to certain species, possibly as the result of seasonal reproductive periods.

Spatial and Temporal Abundance Distribution of Chaetognaths in Eastern Mediterranean Pelagic Waters