Horizontal and vertical distribution of Chaetognatha in the upper 1000 m of the western Sargasso Sea and the Central and South-east Atlantic

The chaetognath abundance, species richness and bathymetric distribution in the upper 1000 m in two regions of the Atlantic Ocean is discussed based on samples collected on two cruises, one to the Sargasso Sea (Northwest Atlantic) on board the R/V R.H. Brown in April 2006, the other along the eastern boundary of the Atlantic (Canary Islands to South Africa) on board the FS Polarstern in November 2007. During both cruises the MOCNESS-1 was used for the sampling. Seventeen species were found in the Sargasso Sea (Ron Brown Cruise) and twenty along the eastern boundary of the Atlantic (the Polarstern Cruise). Sagitta hispida and Krohnitta mutabbii were restricted to the Sargasso Sea, and Sagitta tasmanica, S. gazellae, Eukrohnia macroneura and Krohnitta pacifica to the East Atlantic. In the East Atlantic the most abundant species were Pterosagitta draco, Sagitta enflata, S. serratodentata and Krohnitta subtilis, and in the Sargasso Sea, the most abundant species in Stations 1 and 2 was Sagitta minima. In the other stations S. serratodentata, S. enflata, Pterosagitta draco and Krohnitta subtilis were most abundant. Sagitta zetesios, S. planctonis, S. decipiens, S. sibogae and Eukrohnia fowleri were present at all stations but always in low numbers.