Chaetognatha of the Namibian Upwelling Region: Taxonomy, Distribution and Trophic Position

• DOI: 10.1371/journal.pone.0053839
• Publication Date: 2013-01-16T22:21:05Z
• Authors: Karolina Bohata; Rolf Koppelmann
• Keywords: Mesopelagic zone; Sagitta

In October 2010, the vertical distribution, biodiversity and maturity stages of Chaetognatha species were investigated at four stations located off Walvis Bay, Namibia. Seventeen detected classified as pelagic, shallow-mesopelagic, deep-mesopelagic bathypelagic based upon weighted mean depth derived from their average distribution. High abundances found in upper 100 m all Bay transect with a maximum value 20837 ind. 1000 m−3 outer shelf station near surface. The community was dominated by Serratodentata group. Furthermore, distribution did not seem to be influenced low oxygen concentrations. Stable isotope ratios carbon nitrogen determined for seven different areas northern values δ15N ranged 6.05 ‰ 11.39 ‰, while δ13C varied between −23.89 −17.03 ‰. highest observed break station. lowest Rocky Point offshore station, which statistically other areas. isotopes taxa (Sagitta minima, Planctonis group, Sagitta enflata, decipiens). this case, 6.17 10.38 whereas −22.70 −21.56 S. minima. C- N-content revealed C-values decipiens N-values C:N ratio 5.25 6.20. Overall, are diverse group pelagic food web Benguela Upwelling System act competitors fish larvae jelly preying on copepods.